OBD2 Diagnostic Trouble Codes (DTC)

Diagnostic trouble codes and descriptions for Scania transmissions (GMS) and retarders (RET)

Scania diagnostic trouble codes (DTC): Transmission (GMS) and Retarder (RET) Control System

RET 1

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 1

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The system is down.

Elimination:

Replace the control unit.

RET 2

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

The gearbox control unit, pin 27, found that the voltage is higher or higher than 4.8 V.

Notes:

Retarder is missing.

Elimination:

Check the voltage on pin 27 in the transmission control box electrical connector. Check the oil temperature sensor in the oil pan. Refer to ch. “Check of electromagnetic valves and sensors”.

GMS 2

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

RET 3

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 3

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The system is down.

Elimination:

Replace the control unit.

RET 4

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 4

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Wrong data.

The reasons:

Incorrect configuration.

Notes:

The system is down.

Elimination:

Replace the control unit.

RET 5

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 5

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The system is down.

Elimination:

Replace the control unit.

RET 6

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 6

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Wrong data.

The reasons:

Incorrect configuration.

Notes:

The system is down.

Elimination:

Replace the control unit.

GMS 7

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The system is down.

Elimination:

Replace the control unit.

RET 8

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

RET 9

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 10

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Wrong data.

The reasons:

Incorrect configuration.

Notes:

The system is down.

Elimination:

Replace the control unit.

GMS 290

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Accelerator pedal position sensor

Fault:

The voltage at the accelerator pedal position sensor is too low.

The reasons:

The control unit has detected that the accelerator pedal position sensor supply voltage was less than 0.55 V for more than 5 seconds.

Notes:

Allison DTC: P0122.

The malfunction code is issued only if the engine crankshaft speed exceeds 200 rpm.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check control wiring harness.

Contact your Allison transmission dealer.

GMS 291

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Accelerator pedal position sensor

Fault:

The voltage at the accelerator pedal position sensor is too high.

The reasons:

The control unit has detected that the accelerator pedal position sensor supply voltage was more than 4.75 V for more than 5 seconds.

Notes:

Allison DTC: P0123.

The malfunction code is issued only if the engine crankshaft speed exceeds 200 rpm.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check control wiring harness.

Contact your Allison transmission dealer.

GMS 536

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Transmission oil

Fault:

Transmission oil temperature too high.

The reasons:

The reason for setting this fault code can be long driving and / or driving in difficult conditions without blocking, or prolonged braking by a retarder. This DTC is set if the oil temperature exceeds 126 ° C for at least 10 seconds.

This code can also be set as a result of valve sticking.

Notes:

Allison DTC: P0218.

The control system switches to the Hot Mode, in which the 4th is the highest possible transmission.

Gear shift adaptation is disabled.

The DTC can only be set when the engine speed is more than 200 rpm.

This DTC can be set by setting DTC 1809.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check if the car did not move in extreme conditions without a lock-up when generating this fault code.

Contact your Allison dealer.

RET 1000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal fault

Notes:

The effect of a malfunction can be very different: Opticruise and the retarder may not work at all, or the system may be fully operational.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 1000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Wrong data.

The reasons:

Incorrect configuration.

Notes:

The system is down.

Elimination:

Replace the control unit.

RET 1010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The effect of a malfunction can be very different: Opticruise and the retarder may not work at all, or the system may be fully operational.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 1010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Wrong data.

The reasons:

Incorrect configuration.

Notes:

The system is down.

Elimination:

Reconfigure the control unit configuration using SDP3. Replace the control unit if that does not work.

GMS 1378

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Low system voltage

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0562.

Elimination:

Contact your Allison dealer.

GMS 1538

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Control unit not programmed

Fault:

Incorrect calibration of the control unit.

The reasons:

The control unit is not calibrated or calibrated incorrectly.

Notes:

Allison DTC: P0602.

The control unit switches to the main program mode.

The control unit prohibits the inclusion of all gears.

Elimination:

It is necessary to program the control unit.

Contact your Allison transmission dealer.

GMS 1552

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Transmission Identification

Fault:

Transmission and control unit are incompatible.

The reasons:

The control unit is not compatible with the gearbox.

Notes:

Allison DTC: P0610.

Elimination:

Check that the control unit is compatible with the gearbox.

Contact your Allison transmission dealer.

GMS 1555

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Reconfiguring the processor control unit.

Fault:

Internal malfunction of the control unit, which causes it to restart.

The reasons:

As a result of the failure, the control unit failed to perform two successive checks over a period of time.

Notes:

Allison DTC: P0613.

Elimination:

Contact your Allison transmission dealer.

GMS 1556

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Defective torque limiter between engine and gearbox

Fault:

The engine does not respond to requests for transmission to reduce torque.

The reasons:

The engine does not support this feature.

Notes:

Allison DTC: P0614.

The control unit only allows shifting to second gear and reverse gear.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1588

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Temperature too high in control unit

Fault:

Temperature in control unit too high.

The reasons:

Such an abnormal temperature increase can lead to failure of the control unit components.

Notes:

Allison DTC: P0634.

All solenoid valves are off.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Make sure that there is no dirt or debris that prevents the heat from being removed from the cooling element of the control unit.

Contact your Allison dealer.

GMS 1598

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

There is no accelerator signal in the vehicle configuration.

Fault:

No information from the accelerator pedal.

The reasons:

This may be caused by communication problems on the CAN bus.

Notes:

Allison DTC: P063E.

The control unit uses the basic setting for the accelerator pedal position. The basic setting is 100%, which makes it uncomfortable to change gears when the accelerator pedal is not fully depressed.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Reset the Autodetect message using SDP3 or Allison DOC and check if the DTC remains active.

If this does not work, contact your Allison dealer.

GMS 1599

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

There is no coolant temperature signal in the vehicle configuration.

Fault:

No information is available on the coolant temperature.

The reasons:

This may be caused by communication problems on the CAN bus.

Notes:

Allison DTC: P063F.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Contact your Allison transmission dealer.

GMS 1623

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Supply voltage to the actuator is interrupted

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0657.

Elimination:

Contact your Allison dealer.

GMS 1624

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

The supply voltage from the drive 1 is too low

Fault:

Drive 1 (HSD1) supply voltage too low.

The reasons:

The control unit has detected a voltage of less than 6 V on two solenoids in drive circuit 1. This may be caused by a short to ground in drive circuit 1.

Notes:

Allison DTC: P0658.

All solenoids are de-energized. The included gear in the gearbox is determined by the position of the gear selector and the position of the solenoid rods in the hydraulic system.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check the control unit wiring.

Contact your Allison transmission dealer.

GMS 1625

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

The supply voltage from the drive 1 is too high

Fault:

Drive 1 supply voltage (HSD1) is too high.

The reasons:

The control unit has detected a voltage of 6 V or more in drive circuit 1 (HSD1) after issuing a fault code for two solenoids. This may be caused by a short to battery in drive 1.

Notes:

Allison DTC: P0659.

All solenoid valves are off. The position of the gear selector and the position of the solenoid valves in the hydraulic system make it possible to determine which gear is engaged in the gearbox.

Elimination:

Check the control unit wiring.

Contact your Allison transmission dealer.

GMS 1639

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Internal temperature sensor in the control unit, quality problems.

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0667.

Elimination:

Contact your Allison dealer.

GMS 1640

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Internal temperature sensor in the control unit, low voltage.

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0668.

Elimination:

Contact your Allison dealer.

GMS 1641

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Internal temperature sensor in the control unit, high voltage.

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0669.

Elimination:

Contact your Allison dealer.

GMS 1716

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Oil retarder temperature sensor

Fault:

Wrong signal from the oil temperature sensor in the retarder.

The reasons:

The control unit transmission, pin 3, found that the voltage is higher or was higher than 4.8 V.

Notes:

Retarder is missing.

Elimination:

Check the voltage at pin 3 of the electrical connector for the gearbox control unit. Check retarder oil temperature sensor. Refer to ch. “Check of electromagnetic valves and sensors”.

GMS 1717

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Oil retarder temperature sensor

Fault:

Wrong signal from the oil temperature sensor in the retarder.

The reasons:

The gearbox control unit, pin 3, found that the voltage was below or was below 0.5 V.

Notes:

Retarder is missing.

Elimination:

Check the voltage at pin 3 of the electrical connector for the gearbox control unit. Check retarder oil temperature sensor. Refer to ch. “Check of electromagnetic valves and sensors”.

GMS 1793

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Characteristics of the control system

Fault:

The response from PS1 is invalid.

The reasons:

The following malfunctions are possible:

Low gear oil

Possibly stuck C1 or C2

SS1 shift solenoid may be faulty

PS1 may be stuck or defective

Short to ground

Worn or faulty oil pump

Notes:

Allison DTC: P0701.

The control unit has locked the gearbox in neutral.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1794

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Control System, Transmission Identification

Fault:

The control unit is unable to determine the level of identification of the transmission.

The reasons:

The reason may be the lack of communication between the contact 76 of the control unit and the gearbox or an open wire 176.

Notes:

Allison DTC: P0702.

The control unit identifies the gearbox, determines the type of its components and, based on this, selects the appropriate calibration.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check for any visible damage to the cable 176.

Contact your Allison dealer.

GMS 1795

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Brake switch circuit fault

Fault:

The control unit received the signals of three synchronous accelerations simultaneously with the signals, meaning that the vehicle’s working brake is activated.

The reasons:

Invalid signal from the brake switch.

Notes:

Allison DTC: P0703.

On garbage trucks, the control unit prevents the box from switching from neutral to moving.

The control unit may prohibit the use of a retarder if an accelerator pedal sensor malfunction is also detected.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Contact your Allison transmission dealer.

GMS 1800

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Range switch, high voltage

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0708.

See the Allison DTC description.

Elimination:

Contact your Allison transmission dealer.

GMS 1804

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Oil level sensor, low voltage

Fault:

Voltage from oil level sensor too low.

The reasons:

The control unit has registered the oil level sensor voltage below 0.2998 V.

The reason for this may be one of the following factors:

Transmission oil level too low

External wiring fault

Incorrect connection of the oil level sensor

Internal wiring harness malfunction

Malfunction oil level sensor

Control unit malfunction

Notes:

Allison DTC: P070C.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Check for any visible damage to the external wiring harness.

The oil level should be checked using the control probe.

Contact your Allison dealer.

GMS 1805

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Oil level sensor, high voltage

Fault:

The voltage from the oil level sensor is too high.

The reasons:

The control unit has registered an oil level sensor voltage above 4.5 V.

The reason for this may be one of the following factors:

Transmission oil level too high

External wiring fault

Incorrect connection of the oil level sensor

Internal wiring harness malfunction

Malfunction oil level sensor

Control unit malfunction

Notes:

Allison DTC: P070D

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Check for any visible damage to the external wiring harness.

The oil level should be checked using the control probe.

Contact your Allison dealer.

GMS 1809

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Oil level sensor, unrealistically quick voltage changes

Fault:

The control unit detected unrealistically quick voltage changes at the oil temperature sensor.

The reasons:

A possible cause of this malfunction is damage to the wiring harness.

Notes:

Allison DTC: P0711.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Check for any visible damage to the external wiring harness.

Contact your Allison dealer.

GMS 1810

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Oil temperature sensor, low voltage

Fault:

The control unit has detected that the temperature of the oil in the sump of the engine crankcase exceeded the set value for more than 2.5 seconds.

The reasons:

A possible cause of a malfunction can be damage to the wiring harness or short circuit of the pin 54 to ground.

Notes:

Allison DTC: P0712.

The control unit uses the default temperature values.

For the DTC to be set, the engine must operate and have a temperature above 20ºC for 20 seconds, provided that the engine has been running for less than 10 minutes.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check for any damage or short circuit in the outer cable harness.

Contact your Allison dealer.

GMS 1811

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Oil temperature sensor, high voltage

Fault:

The control unit determined that the crankcase oil temperature did not exceed the calibrated value for more than 2.5 seconds.

The reasons:

The cause of the malfunction may be damage to the wiring harness or short circuit of the pin 54 to the battery. If both codes 2185 and / or 2743 are installed, it is highly likely that one of the wires connected to pins 54, 35 and 75 is shorted to battery. Also, the DTC can be set as a result of a short circuit in the wiring harness connected to pin 54 or 58.

Notes:

Allison DTC: P0713.

The control unit uses the default temperature values.

For the DTC to be set, the engine must operate and have a temperature above 20ºC for 20 seconds, provided that the engine has been running for less than 10 minutes.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check for any damage or short circuit in the outer cable harness.

Contact your Allison dealer.

GMS 1814

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Turbine shaft speed sensor, signal interference

Fault:

The control unit detects interference in the signal from the turbine shaft speed sensor

The reasons:

A possible cause of a malfunction may be damage to the wiring harness or a malfunction of the turbine shaft speed sensor.

Notes:

Allison DTC: P0716.

The malfunction code is registered when one of the following conditions is met:

Excessively large changes in the speed of the turbine at speeds above 800 rpm for more than 0.15 seconds.

Voltage noise from the sensor.

The wires to the sensor are reversed, the required transmission is not neutral, the following clutch control is completed and the turbine speed exceeds 100 rpm.

If a malfunction occurs after the gear shift, when the movement was carried out on the forward gear, the gearbox leaves the current gear.

If a malfunction occurs during a gear shift, when the movement was carried out on a forward gear, the gearbox returns to the previous gear and only after that shifts to the necessary gear.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The DTC is registered only in vehicles whose control unit has a fire vehicle calibration.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Check for any damage or short circuit in the outer cable harness.

Contact your Allison dealer.

GMS 1815

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Turbine shaft speed sensor, no signal

Fault:

No signal from the turbine shaft speed sensor

The reasons:

A possible cause of a malfunction may be damage to the wiring harness or a malfunction of the turbine shaft speed sensor.

Notes:

Allison DTC: P0711.

The malfunction code is registered when the following conditions are met:

Significant changes in the frequency of rotation of the turbine (at least 800 rev / min).

Excessively low turbine speed. The frequency of rotation of the turbine is less than 61 rpm, and the frequency of rotation of the output shaft is at least 500 rpm for more than 1 second.

To register a DTC, the following conditions must be met:

The control unit has a fire car calibration.

Shifting is completed.

The engine is running.

The current transmission is not neutral.

There are no basic conditions for adjusting the hydraulic system due to the loss of ignition voltage.

The oil temperature in the sump of the engine crankcase exceeds -1.1ºC.

If a malfunction occurs after the gear shift, when the movement was carried out on the forward gear, the gearbox leaves the current gear.

If a malfunction occurs during a gear shift, when the movement was carried out on a forward gear, the gearbox returns to the previous gear and only after that shifts to the necessary gear.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Check the wiring, replace the sensor with a new one, and verify that the fault is resolved.

Contact your Allison dealer.

GMS 1816

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Oil temperature sensor in the oil pan

Fault:

Wrong signal from pallet oil temperature sensor.

The reasons:

The gearbox control unit, pin 27, found that the voltage is higher or higher than 4.8 V.

Notes:

Retarder is missing.

Elimination:

Check the voltage on pin 27 in the transmission control box electrical connector. Check the oil temperature sensor in the oil pan. Refer to ch. “Check of electromagnetic valves and sensors”.

GMS 1817

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Oil temperature sensor in the oil pan

Fault:

Wrong signal from pallet oil temperature sensor.

The reasons:

The gearbox control unit, pin 27, found that the voltage was below or below 2.6 V.

Notes:

Retarder is missing.

Elimination:

Check the voltage on pin 27 in the transmission control box electrical connector. Check the oil temperature sensor in the oil pan. Refer to ch. “Check of electromagnetic valves and sensors”.

GMS 1817

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

ABS brake switch, weak signal

Fault:

The control unit is configured to receive status signals from the ABS system and detects acceleration when the ABS system is in the active state.

The reasons:

The fault may be in the ABS / EBS system or the gearbox control unit.

Notes:

Allison DTC: P0719.

The control unit can release the lock.

The control unit switches to the basic setting mode, i.e. the ABS system becomes inactive.

Elimination:

Use SDP3 or Allison diagnostic tool to check the condition of the ABS through the CAN bus. If there is no malfunction in the ABS / EBS system, contact your Allison dealer.

GMS 1818

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

RELS, abnormally weak signal

Fault:

The control unit is configured to receive RELS signals and detects acceleration when the RELS is in the active state.

The reasons:

The cause of this fault may be a fault in the wiring harness or control unit.

Notes:

Allison DTC: P071A.

RELS (Reduced Engine Load at Stop) is a function that reduces the load on the gearbox.

The control unit prevents activation of the RELS.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check for any damage or short-circuits in the external wiring harness, especially in the wire leading to pin 23 through which the function is activated. If the fault is not identified, contact your Allison dealer.

GMS 1821

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Shift lock function

Fault:

Wrong input to control unit to activate shift lock function.

The reasons:

The control unit has detected two different states on pins 1 and 42 of the control unit.

Notes:

Allison DTC: P071D.

The shift lock feature is enabled when pins 1 and 3 are connected, and pin 42 is shorted to ground. The fault code can only be set if the vehicle control unit is programmed for fire engines.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check for damage or short circuits in the external wiring harness and switches connected to pins 1, 3 and 42.

If the fault is not identified, contact your Allison dealer.

GMS 1824

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Output Shaft Speed Sensor

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0720

Elimination:

Contact your Allison dealer.

GMS 1825

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Output speed sensor, signal interference

Fault:

The control unit has detected deviations from the rotational speed sensor located on the secondary shaft.

The reasons:

A possible cause of a malfunction can be damage to the wiring harness or malfunction of the rotational speed sensor on the output shaft.

Notes:

Allison DTC: P0721.

The DTC can only be set if the following conditions are met.

The frequency of rotation of the output shaft exceeds 200 rpm.

The gearshift must be completed and a non-neutral gear selected.

The DTC can only be set on vehicles whose control units are programmed for fire engines.

If a malfunction occurs while driving with the selected forward gear and the gear shift has been performed, the gearbox saves the selected gear.

If a malfunction occurs while driving with the selected range of forward gears in the gearshift process, the gearbox returns to the previous gear, after which the specified gearshift is performed.

Torque lock is not activated.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check for any damage or short circuit in the outer cable harness.

Contact your Allison dealer.

GMS 1826

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Output shaft speed sensor, no signal

Fault:

There are no signals from the speed sensor located on the secondary shaft.

The reasons:

A possible cause of a malfunction can be damage to the wiring harness or a speed sensor malfunction.

Notes:

Allison DTC: P0722.

The malfunction code is registered when one of the following conditions is met:

Significant changes in shaft speed (at least 600 rpm) in neutral gear.

Shaft speed is less than 61 rpm in 3, 4 or 5 gear for more than 1 second.

The shaft rotational speed is less than 61 rpm for more than 1 second when the 2nd gear is engaged, and the effective torque of the engine is +/- 1 Nm or the turbine speed exceeds 800 rpm.

To register a DTC, the following conditions must be met:

The control unit has a fire car calibration.

Shifting is completed.

The engine is running.

The current transmission is not neutral.

There are no basic conditions for adjusting the hydraulic system due to the loss of ignition voltage.

The oil temperature in the sump of the engine crankcase exceeds -1.1ºC.

Turbine speed exceeds 600 rpm.

If a malfunction occurs after the gear shift, when the movement was carried out on the forward gear, the gearbox leaves the current gear.

If a malfunction occurs during a gear shift, when the movement was carried out on a forward gear, the gearbox returns to the previous gear and only after that shifts to the necessary gear.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Check the wiring, replace the sensor with a new one, and verify that the fault is resolved.

Contact your Allison dealer.

GMS 1830

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Engine crankshaft speed sensor, signal interference

Fault:

The control unit has detected deviations of signals coming from the engine crankshaft speed sensor located on the primary shaft.

The reasons:

A possible cause of a malfunction can be damage to the wiring harness or a malfunction in the engine crankshaft speed sensor.

Notes:

Allison DTC: P0726.

The DTC can only be set if the check is activated during calibration, the engine speed exceeds 600 rpm and a non-neutral gear is selected.

The fault code is set when one of the following conditions is met.

Implausibly large changes in engine speed for more than 0.15 seconds when the speed exceeds 600 rpm.

Violation of the signal from the sensor.

The control unit sets the engine speed to the same as the turbine speed.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring. Replace the sensor with a new one and verify that the fault is fixed.

Contact your Allison dealer.

GMS 1831

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Engine Speed Sensor, No Signal

Fault:

There are no signals from the engine crankshaft speed sensor located on the secondary shaft.

The reasons:

A possible cause of a malfunction can be damage to the wiring harness or a speed sensor malfunction.

Notes:

Allison DTC: P0727.

The DTC can be set only if the check is activated during calibration. To test a low engine speed, the turbine speed should exceed 400 rpm and the ignition must be turned on.

The fault code is set when one of the following conditions is met.

Implausibly large changes (minimum 1040 rpm) engine speed.

Shaft speed less than 61 rpm lasts more than 4 seconds.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring. Replace the sensor with a new one and verify that the fault is fixed.

Contact your Allison dealer.

GMS 1833

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Invalid gear ratio in sixth gear

Fault:

The actual gear ratio of the 6th gear does not match the calculated value. The gear ratio is based on the rotational speeds of the turbine shaft and the output shaft. The measured gear ratio is compared with the passport value for the 6th gear.

The reasons:

It is possible that the malfunction is due to problems in the mechanical system, for example, with C2 and C4 for 6th gear.

Notes:

Allison DTC: P0729.

The fault code is set in stationary conditions when the calculated gear ratio is different from the actual gear ratio for more than 2 seconds.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

Gear shift is not performed.

There are no constant values of the characteristics of the hydraulic system by default.

The frequency of rotation of the output shaft exceeds 200 rpm.

Procedures for starting or shutting down the engine are not performed.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit attempts to engage the 5th gear. If this does not work, the control unit sets the 3rd gear.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1840

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Invalid gear ratio in neutral

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0730

Elimination:

Contact your Allison dealer.

GMS 1841

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Wrong gear ratio in first gear

Fault:

The actual gear ratio of the 1st gear does not match the calculated value. The gear ratio is determined based on the rotational speed of the turbine shaft and the secondary shaft. The measured gear ratio is compared with the passport value for 1st gear.

The reasons:

It is possible that the malfunction is due to problems in the mechanical system, for example with C1 and C5 for 1st gear.

Notes:

Allison DTC: P0731.

The fault code is set in stationary conditions, when the calculated gear ratio is different from the actual gear ratio for the 1st gear.

To register a DTC, the following conditions must be met:

The hydraulic system is under pressure.

Gear shift is not performed.

There are no constant default hydraulic conditions.

The frequency of rotation of the output shaft above 200 rpm.

The engine start or shutdown procedure is not performed.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The control unit attempts to engage 2nd gear. If this does not work, the control unit sets the 5th gear.

While the DTC is active, the control unit ignores all data from the gear selector.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Contact your Allison dealer.

GMS 1842

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Wrong gear ratio in second gear

Fault:

The actual gear ratio of the 2nd gear does not match the calculated value. The gear ratio is based on the rotational speeds of the turbine shaft and the output shaft. The measured gear ratio is compared with the passport value for 2nd gear.

The reasons:

It is possible that the malfunction is due to problems in the mechanical system, for example with clutches C1 and C4 for 2nd gear.

Notes:

Allison DTC: P0732.

The fault code is set in stationary conditions, when the calculated gear ratio for the second gear is different from the actual gear ratio.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

Gear shift is not performed.

There are no constant values of the characteristics of the hydraulic system by default.

The frequency of rotation of the output shaft exceeds 200 rpm.

Procedures for starting or shutting down the engine are not performed.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit attempts to engage the 3rd gear. If this does not work, the control unit sets the 5th gear.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1843

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Wrong gear ratio in third gear

Fault:

The actual gear ratio of the 3rd gear does not correspond to the calculated value. The gear ratio is based on the rotational speeds of the turbine shaft and the output shaft. The measured gear ratio is compared with the passport value for the 3rd gear.

The reasons:

It is possible that the malfunction is due to problems in the mechanical system, for example with clutches C1 and C3 for 3rd gear.

Notes:

Allison DTC: P0733.

The fault code is set in stationary conditions, when the estimated gear ratio for third gear is different from the actual gear ratio.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

Gear shift is not performed.

There are no constant values of the characteristics of the hydraulic system by default.

The frequency of rotation of the output shaft exceeds 200 rpm.

Procedures for starting or shutting down the engine are not performed.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit attempts to engage the 4th gear. If this does not work, the control unit sets the 6th gear.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1844

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Invalid gear ratio in fourth gear

Fault:

Actual gear ratio 4th gear does not match the calculated value. The gear ratio is based on the rotational speeds of the turbine shaft and the output shaft. The measured gear ratio is compared with the passport value for 4th gear.

The reasons:

It is possible that the malfunction is due to problems in the mechanical system, for example with clutches C1 and C2 for 4th gear.

Notes:

Allison DTC: P0734.

The malfunction code is set in stationary conditions, when the calculated gear ratio for fourth gear differs from the actual gear ratio.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

Gear shift is not performed.

There are no constant values of the characteristics of the hydraulic system by default.

The frequency of rotation of the output shaft exceeds 200 rpm.

Procedures for starting or shutting down the engine are not performed.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit attempts to engage the 5th gear. If this does not work, the control unit sets the 3rd gear.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1845

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Invalid gear ratio in fifth gear

Fault:

The actual gear ratio of the 5th gear does not match the calculated value. The gear ratio is based on the rotational speeds of the turbine shaft and the output shaft. The measured gear ratio is compared with the passport value for the 5th gear.

The reasons:

It is possible that the malfunction is due to problems in the mechanical system, for example with clutches C2 and C3 for 5th gear.

Notes:

Allison DTC: P0735.

The fault code is set in stationary conditions, when the calculated gear ratio for the fifth gear is different from the actual gear ratio.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

Gear shift is not performed.

There are no constant values of the characteristics of the hydraulic system by default.

The frequency of rotation of the output shaft exceeds 200 rpm.

Procedures for starting or shutting down the engine are not performed.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit attempts to engage the 6th gear. If this does not work, the control unit sets the 3rd gear.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1846

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Incorrect gear ratio on reverse gear

Fault:

The actual gear ratio of the reverse gear does not match the calculated value. The gear ratio is based on the rotational speeds of the turbine shaft and the output shaft. The measured gear ratio is compared with the passport value for the reverse gear.

The reasons:

The reason for this may be a mechanical failure, for example, reverse gear clutch C3 and C5 malfunction.

Notes:

Allison DTC: P0736.

The malfunction code is set in stationary conditions when the calculated gear ratio for the reverse gear is different from the actual gear ratio.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

Gear shift is not performed.

There are no constant values of the characteristics of the hydraulic system by default.

The frequency of rotation of the output shaft exceeds 200 rpm.

Procedures for starting or shutting down the engine are not performed.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit locks the gearbox in neutral.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1857

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Locking clutch seized in closed position.

Fault:

The control unit has determined that the torque converter overload clutch slips.

The reasons:

A possible cause is a solenoid controlling the lock.

Notes:

Allison DTC: P0741.

A fault code is set when the control unit detects that the torque converter lock-up clutch slips at more than 150 rpm for more than 25.5 seconds.

To set the DTC, the following conditions must be met.

Engine speed exceeds 200 rpm.

Front gear shift range selected.

The accelerator pedal is depressed by more than 75%.

The oil temperature in the pan is between 25ºC and 130ºC.

More than 6 seconds should elapse after the lock has fixed the transfer.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1874

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Shift solenoid valve SS1 stuck in the on position

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0752

Elimination:

Contact your Allison dealer.

GMS 1910

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS2 solenoid stuck in disconnected position

Fault:

The control unit has detected a slip in the coupling (C2 or C3), the hydraulic pressure of which is provided by the valve PCS2.

The reasons:

The reason may be as follows:

Abnormal signal from the turbine speed sensor or the secondary shaft.

Leak or blockage in the power supply circuit of a specific clutch.

Faulty solenoid valve PCS2.

Jamming control valve for PCS2.

Jammed check valve for C2.

Notes:

Allison DTC: P0776.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

The rotational speed of the output shaft exceeds 125 rpm.

Turbine speed exceeds 60 rpm.

Cold start is not activated.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The control unit gives the command to activate the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1911

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS2 solenoid stuck in connected position

Fault:

The PCS2 still powers the clutch, despite the fact that the clutch must be turned off. A fault is recorded if the control unit determines that the previous gear shift has been engaged for an extended period of time, despite the fact that the clutch received a trip signal.

The reasons:

The reason may be the following:

An incorrect signal from the turbine shaft or output shaft speed sensor.

Faulty solenoid PCS2.

Obstacle in the circuit for disengaging the clutch C2.

Seized control valve for PCS2.

Notes:

Allison DTC: P0777.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

The rotational speed of the output shaft exceeds 125 rpm.

Turbine speed exceeds 60 rpm.

Cold start is not activated.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The control unit attempts to enable the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1942

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS3 solenoid stuck in disconnected position

Fault:

The control unit has detected a slip in the coupling (C3 or C5), the hydraulic pressure of which is provided by the valve PCS3.

The reasons:

The reason may be as follows:

Abnormal signal from the turbine speed sensor or the secondary shaft.

Leak or blockage in the power supply circuit of a specific clutch.

Faulty solenoid valve.

Jamming control valve for PCS3.

Seized gate valve for C1 or C2.

Notes:

Allison DTC: P0796.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

The rotational speed of the output shaft exceeds 125 rpm.

Turbine speed exceeds 60 rpm.

Cold start is not activated.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The control unit attempts to enable the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 1943

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS3 solenoid stuck in connected position

Fault:

The PCS3 still powers the clutch, despite the fact that the clutch must be turned off. A fault is recorded if the control unit determines that the previous gear shift has been engaged for an extended period of time, despite the fact that the clutch received a trip signal.

The reasons:

The reason may be the following:

An incorrect signal from the turbine shaft or output shaft speed sensor.

Obstacle in the C3 or C4 clutch release circuit.

Faulty solenoid PCS3.

Seized control valve for PCS3.

Notes:

Allison DTC: P0797.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

The frequency of rotation of the output shaft exceeds 200 rpm.

Turbine speed exceeds 200 rpm.

Cold start is not activated.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The control unit attempts to enable the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

RET 2000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The effect of a malfunction can be very different: Opticruise and the retarder may not work at all, or the system may be fully operational.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 2000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The system is down.

Elimination:

Replace the control unit.

RET 2010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The effect of a malfunction can be very different: Opticruise and the retarder may not work at all, or the system may be fully operational.

Elimination:

If the control unit software update fails, try the update again. Otherwise, erase all fault codes, stop and restart the car engine. If the DTCs continue to display, replace the control unit.

GMS 2010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The system is down.

Elimination:

Replace the control unit.

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y17

Fault:

Wrong signal from solenoid valve Y17 for coupling A.

The reasons:

The gearbox control unit, pin 10, has detected a short circuit to the + battery.

The voltage was above 7.53 V.

Notes:

All solenoid valves are disabled and the system switches to “Neutral” mode.

When this DTC is generated, the alarm on the instrument cluster is lit.

Elimination:

Check the signal at pin 10 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2114

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Pressure switch 1 in the transmission (PS1), low signal in the circuit

Fault:

PS1 does not create pressure when needed.

The reasons:

A possible cause of a malfunction can be damage to the wiring harness or a PS1 malfunction.

Notes:

Allison DTC: P0842.

The control unit sets a fault code if it detects that the PS1 is not under excessive pressure for any of the following reasons.

Clutch C5 is full, and the solenoid PCS2 is commanded to turn on.

Clutch C5 is drained and both block valves are enabled.

After changing the locking valve mode, as a result of which both valves open.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

Resetting is complete.

The oil temperature in the pan exceeds -15 ° C.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The control unit attempts to enable the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Ensure that there is no damage to the wiring between the gearbox and the control unit.

Contact your Allison dealer.

GMS 2115

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Pressure switch 1 in the transmission (PS1), high signal in the circuit

Fault:

PS1 creates pressure when not needed.

The reasons:

A possible cause of a malfunction can be damage to the wiring harness or a PS1 malfunction.

Notes:

Allison DTC: P0843.

The control unit registers a malfunction code if it determines that the PS1 is under excessive pressure due to one of the following reasons:

Clutch C5 is emptied, solenoid valve PCS2 has received an OFF command and at least one of the shut-off valves C1 or C2 is turned off.

After changing the state of the shut-off valves, when both shut-off valves were turned on, then at least one of the shut-off valves C1 or C2 turned off.

To register a DTC, the following conditions must be met:

The hydraulic system is under pressure.

Reconfiguration completed.

The oil temperature in the sump of the engine crankcase exceeds -15ºC.

Torque lock is not activated.

The control unit switches off the self-tuning gear.

The control unit blocks the current transmission.

While the DTC is valid, the control unit ignores all data received from the gear selector.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Ensure that there is no damage to the wiring between the gearbox and the control unit.

Contact your Allison dealer.

GMS 2119

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Pressure switch 2 in the gearbox (PS2), low signal in the circuit

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0847.

Elimination:

Contact your Allison dealer.

GMS 2120

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Pressure switch 2 in the gearbox (PS2), high signal in the circuit

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P0848.

Elimination:

Contact your Allison dealer.

GMS 2176

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Supply voltage control unit (U30), incorrect shutdown

Fault:

The battery supply voltage disappears until the shutdown process is completed, and the engine continues to run.

The reasons:

The cause of the malfunction may be the disconnection of the battery before the ignition voltage is turned off (U15). Another cause may be damage to the wiring harness of the gearbox.

Notes:

Allison DTC: P0880.

The malfunction code is set upon future startup if the battery voltage disappears before the completion of the previous shutdown operation. This check is performed continuously.

The control unit loses the shift adaptation information gathered while driving.

The control unit returns to the last saved adaptation values.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Ensure that there is no damage to the wiring between the gearbox and the control unit.

Contact your Allison dealer.

GMS 2177

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Control unit supply voltage (U30), interference

Fault:

The control unit has detected fluctuations in the supply voltage (U30) in a wide range.

The reasons:

The possible cause of a malfunction may be:

Malfunction of the battery.

Oxidation of cables and terminals of the battery.

Loose contact or damage to wiring harnesses.

Internal malfunction in the control unit.

Notes:

Allison DTC: P0881.

This DTC is issued only if the engine speed exceeds 500 rpm for more than 1.5 seconds.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check the battery and its associated wiring harness. Ensure that the wiring between the gearbox and the control unit is not damaged. If the fault is not identified, contact your Allison dealer.

GMS 2178

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Control unit supply voltage (U30) too low

Fault:

The voltage supply of the control unit is below the nominal value.

The reasons:

The possible cause of a malfunction may be:

Malfunction of the battery.

Oxidation of cables and terminals of the battery.

Loose contact or damage to wiring harnesses.

Notes:

Allison DTC: P0882.

In order for the DTC to be set, the engine speed must be above 450 rpm for more than 10 seconds.

The lock cannot be enabled.

The control unit disables gear shift adaptation.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the battery and its associated wiring harness. Ensure that the wiring between the gearbox and the control unit is not damaged. If the fault is not identified, contact your Allison dealer.

GMS 2179

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Control unit supply voltage (U30) too high

Fault:

The voltage supply of the control unit exceeds the nominal value.

The reasons:

The reason for this failure may be as follows:

Malfunction of the car charging system.

Bad contact or damage to the wiring harness.

The 12 V control unit is connected to the 24 V electrical system.

Notes:

Allison DTC: P0883.

This DTC is issued only if the engine’s crankshaft speed exceeds 450 rpm for more than 10 seconds.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check the battery, its associated wiring harness and vehicle alternator. Ensure that the wiring between the gearbox and the control unit is not damaged. If the fault is not identified, contact your Allison dealer.

GMS 2186

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Transmission oil filter operation in gearbox deteriorated

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P088A.

Elimination:

Contact your Allison dealer.

GMS 2187

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

The operation of the transmission oil filter in the gearbox is significantly degraded.

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P088B.

Elimination:

Contact your Allison dealer.

GMS 2196

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Abnormally high transmission slip rate

Fault:

The frequency of rotation of the turbine shaft exceeds the specified value when the 1st gear is engaged.

The reasons:

No description

Notes:

Allison DTC: P0894.

The fault code is set if the first gear is selected and the turbine speed exceeds the calibrated value.

Possible cause of the malfunction code.

Non-standard oil level in the gearbox.

Controller solenoid valve sticking.

Stuck lock valve for C1 or C2.

Incorrect pressure control or switching solenoid control.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

There are no constant values of the characteristics of the hydraulic system by default.

Procedures for starting or shutting down the engine are not performed.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit commands the activation of the 1st gear.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the oil level in the crankcase.

Contact your Allison transmission dealer.

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y16

Fault:

Wrong signal from solenoid valve Y16 for clutch B.

The reasons:

The gearbox control unit, pin 4, has detected a short circuit to the + battery.

The voltage was above 7.53 V.

Notes:

All solenoid valves are disabled and the system switches to “Neutral” mode.

When this DTC is generated, the alarm on the instrument cluster is lit.

Elimination:

Check the signal at pin 4 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2312

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y15

Fault:

Wrong signal from solenoid valve Y15 for coupling C.

The reasons:

The control unit transmission, pin 5, found a gap in the wiring.

The voltage was above 4.5 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal at pin 5 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2313

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y15

Fault:

Wrong signal from solenoid valve Y15 for coupling C.

The reasons:

The gearbox control unit, pin 5, has detected a short to ground.

The voltage was below 19 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal at pin 5 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2314

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y15

Fault:

Wrong signal from solenoid valve Y15 for coupling C.

The reasons:

The gearbox control unit, pin 5, has detected a short circuit to the + battery.

The voltage was above 7.53 V.

Notes:

All solenoid valves are disabled and the system switches to “Neutral” mode.

When this DTC is generated, the alarm on the instrument cluster is lit.

Elimination:

Check the signal at pin 5 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2400

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Modulating solenoid of the PCS main unit, interference

Fault:

The control unit has detected an open circuit break in the modulating solenoid of the main unit.

The reasons:

A possible cause of this fault code may be a break in the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0960.

This DTC is issued when the control unit detects an open in the return circuit of the modulating solenoid for more than 2 seconds.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit. If no fault is found, contact your Allison dealer.

GMS 2401

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Modulating solenoid of the PCS main unit, interference

Fault:

The control unit detected interference in the feedback circuit of the modulating solenoid of the main unit.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0961.

A fault code is set when the control unit registers a break in the return circuit of the main control valve for more than 2 seconds.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit. If no fault is found, contact your Allison dealer.

GMS 2402

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Modulating solenoid PCS main unit, short to ground (U31)

Fault:

The control unit has detected a short to ground for the return circuit of the main solenoid valve with a smooth characteristic.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0962.

A fault code is set when the control unit detects a short to ground in the return circuit of the main control valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit. If no fault is found, contact your Allison dealer.

GMS 2403

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS main modulating solenoid valve, short to battery + (U30)

Fault:

The control unit has detected a short circuit to the positive pole of the return circuit of the main solenoid valve with a smooth characteristic.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0963.

A fault code is set when the control unit detects a short to battery in the return circuit of the main control valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit. If no fault is found, contact your Allison dealer.

GMS 2404

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS2, open circuit

Fault:

The control unit has detected a break in the reverse circuit of the PCS2 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the wiring harness of the circuit of the electric circuit of the solenoid valve.

Notes:

Allison DTC: P0964.

A fault code is set when the control unit detects an open circuit in the reverse circuit of the PCS2 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and control unit, especially the wires leading to pins 71 and 52 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2405

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS2, interference

Fault:

The control unit has detected interference in the reverse circuit of the PCS2 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0965.

A fault code is set when the control unit detects a break in the return circuit of the PCS2 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire going to pin 52 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2406

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS2, short to ground (U31)

Fault:

The control unit has detected a short to ground in the return circuit of the PCS2 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0966.

A fault code is set when the control unit detects a short to ground on the return circuit of the PCS2 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire going to pin 52 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2407

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS2, short to battery + (U30)

Fault:

The control unit has detected a short circuit to the positive pole in the return circuit of the solenoid valve PCS2.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0967.

A fault code is set when the control unit detects a short to battery in the reverse circuit of the PCS2 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire going to pin 52 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2408

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS3, open circuit

Fault:

The control unit has detected a break in the reverse circuit of the PCS3 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the wiring harness of the circuit of the electric circuit of the solenoid valve.

Notes:

Allison DTC: P0968.

A fault code is set when the control unit detects an open circuit in the reverse circuit of the PCS3 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and control unit, especially the wires leading to pins 71 and 33 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2409

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS3, interference

Fault:

The control unit has detected interference in the reverse circuit of the PCS3 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0969.

A fault code is set when the control unit detects a break in the return circuit of the PCS3 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 33 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2412

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y14

Fault:

Wrong signal from solenoid valve Y14 for clutch D.

The reasons:

The control unit transmission, pin 9, found a gap in the wiring.

The voltage was above 4.5 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal at pin 9 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2413

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y14

Fault:

Wrong signal from solenoid valve Y14 for clutch D.

The reasons:

The gearbox control unit, pin 9, has detected a short to ground.

The voltage was below 19 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal at pin 9 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2414

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y14

Fault:

Wrong signal from solenoid valve Y14 for clutch D.

The reasons:

The gearbox control unit, pin 9, has detected a short circuit to the + battery.

The voltage was above 7.53 V.

Notes:

All solenoid valves are disabled and the system switches to “Neutral” mode.

When this DTC is generated, the alarm on the instrument cluster is lit.

Elimination:

Check the signal at pin 9 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2416

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS3 short circuit to ground (U31)

Fault:

The control unit has detected a short to ground in the return circuit of the PCS3 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0970.

A fault code is set when the control unit detects a short to ground in the return circuit of the PCS3 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire going to pin 52 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2417

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS3, short to battery + (U30)

Fault:

The control unit has detected a short circuit to the positive pole in the return circuit of the PCS3 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0971.

A fault code is set when the control unit detects a short to battery in the reverse circuit of the PCS3 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 33 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2419

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Shift Solenoid SS1 Short to Ground (U31)

Fault:

The control unit has detected a short to ground or an open circuit in the return circuit of the SS1 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0973.

A fault code is set when the control unit detects a short to ground or an open circuit in the return circuit of the SS1 solenoid for more than 0.125 seconds.

The DTC can be set only during the start-up of the control unit or if the engine speed exceeds 200 rpm.

The control unit turns off all solenoids.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 51 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2420

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Shift Solenoid SS1, Short to + Battery (U30)

Fault:

The control unit has detected a short to the positive pole of the return circuit of the solenoid valve SS1.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0974.

A fault code is set when the control unit detects a short to battery in the return circuit of the SS1 solenoid valve for more than 0.125 seconds.

The DTC can be set only during the start of the control unit, or at a frequency of rotation of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 51 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2421

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Shift solenoid valve SS2, open circuit

Fault:

The control unit has detected a break in the reverse circuit of the SS2 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0975.

A fault code is set when the control unit detects an open circuit in the return circuit of the solenoid SS2 for more than 2 seconds.

The DTC can be set only during the start-up of the control unit or if the engine speed exceeds 200 rpm.

The accumulator cannot be used on gearboxes with a retarder.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the gearbox and control unit, especially the wires leading to pins 31 and 19 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2422

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Shift Solenoid SS2, Short to Ground (U31)

Fault:

The control unit has detected a short to ground on the return circuit of the SS2 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0976.

A fault code is set when the control unit detects a short to ground in the return circuit of the solenoid SS2 for more than 0.125 seconds.

The DTC can be set only during the start-up of the control unit or if the engine speed exceeds 200 rpm.

The control unit allows the inclusion of all gears except the 1st.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction. Torque lock is not activated.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 19 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2423

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

SS2 Shift Solenoid, Short to + Battery (U30)

Fault:

The control unit has detected a short to the positive pole of the return circuit of the SS2 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P0977.

A fault code is set when the control unit detects a short to battery in the return circuit of the SS2 solenoid for more than 0.125 seconds.

The DTC can be set only during the start-up of the control unit or if the engine speed exceeds 200 rpm.

The control unit allows the inclusion of all gears except the 1st.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 19 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2441

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Retarder pressure sensor, low voltage

Fault:

The control unit has detected a too low voltage (0 V) from the retarder pressure sensor.

The reasons:

The cause of the malfunction may be a short circuit to earth or an open circuit in one of the cables going to terminals 12 and 44 on the control unit.

Notes:

Allison DTC: P0989.

The fault code is set when the control unit detects zero voltage (0 V) from the retarder pressure sensor for more than 10 seconds.

The fault code can only be set if the engine speed exceeds 200 rpm, the power supply voltage of the components and the ignition is more than 9 V and less than 32 V. Electronic braking should be activated by the control unit.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wires going to pins 12 and 44 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2448

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Retarder pressure sensor, high voltage

Fault:

The control unit has registered a voltage of 5 V or more from the retarder pressure sensor.

The reasons:

A possible cause of this DTC is a short to battery in one of the wires connected to terminal 12 or 44 of the control unit. Also, the DTC can be set as a result of a break in the analog return wire connected to terminal 58 of the control unit.

Notes:

Allison DTC: P0990.

A fault code is set when the control unit detects a voltage of 5 V or more from the retarder pressure sensor for more than 10 seconds.

The fault code can only be set if the engine speed exceeds 200 rpm, the power supply voltage of the components and the ignition is more than 9 V and less than 32 V. Electronic braking must be activated by the control unit.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wires going to pins 12, 44 and 58 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 2512

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y13

Fault:

Wrong signal from Y13 solenoid valve for E clutch.

The reasons:

The control unit transmission, pin 54, found a gap in the wiring.

The voltage was above 4.5 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal at electrical connector pin 54 for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2513

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y13

Fault:

Wrong signal from Y13 solenoid valve for E clutch.

The reasons:

The gearbox control unit, pin 54, has detected a short to ground.

The voltage was below 19 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal at electrical connector pin 54 for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2514

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y13

Fault:

Wrong signal from Y13 solenoid valve for E clutch.

The reasons:

The gearbox control unit, pin 54, has detected a short circuit to the + battery.

The voltage was above 7.53 V.

Notes:

All solenoid valves are disabled and the system switches to “Neutral” mode.

When this DTC is generated, the alarm on the instrument cluster is lit.

Elimination:

Check the signal at electrical connector pin 54 for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2612

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y12

Fault:

Wrong signal from solenoid valve Y12 for coupling F.

The reasons:

The gearbox control unit, pin 29, found a gap in the wiring.

The voltage was above 4.5 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal on the electrical connector pin 29 for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2613

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y12

Fault:

Wrong signal from solenoid valve Y12 for coupling F.

The reasons:

The gearbox control unit, pin 29, has detected a short to ground.

The voltage was below 19 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal on the electrical connector pin 29 for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2614

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y12

Fault:

Wrong signal from solenoid valve Y12 for coupling F.

The reasons:

The gearbox control unit, pin 29, has detected a short circuit to the + battery.

The voltage was above 7.53 V.

Notes:

All solenoid valves are disabled and the system switches to “Neutral” mode.

When this DTC is generated, the alarm on the instrument cluster is lit.

Elimination:

Check the signal on the electrical connector pin 29 for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2712

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y11

Fault:

Wrong signal from solenoid valve Y11 for clutch G.

The reasons:

The gearbox control unit, pin 30, found a gap in the electrical wiring.

The voltage was above 4.5 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal at pin 30 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2713

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y11

Fault:

Wrong signal from solenoid valve Y11 for clutch G.

The reasons:

The gearbox control unit, pin 30, has detected a short to ground.

The voltage was below 19 V.

Notes:

All solenoid valves are disabled and the system switches to the neutral position (“Neutral”).

Elimination:

Check the signal at pin 30 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2714

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y11

Fault:

Wrong signal from solenoid valve Y11 for clutch G.

The reasons:

The gearbox control unit, pin 30, has detected a short circuit to the + battery.

The voltage was above 7.53 V.

Notes:

All solenoid valves are disabled and the system switches to “Neutral” mode.

When this DTC is generated, the alarm on the instrument cluster is lit.

Elimination:

Check the signal at pin 30 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2812

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y18

Fault:

Wrong signal from Y18 solenoid valve to block.

The reasons:

The control unit transmission, pin 11, found a gap in the wiring.

The voltage was above 4.5 V.

Notes:

The system switches to the emergency program mode.

Elimination:

Check the signal at pin 11 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2813

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y18

Fault:

Wrong signal from Y18 solenoid valve to block.

The reasons:

The gearbox control unit, pin 11, has detected a short to ground.

The voltage was below 19 V.

Notes:

The system switches to the emergency program mode.

Elimination:

Check the signal at pin 11 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2814

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y18

Fault:

Wrong signal from Y18 solenoid valve to block.

The reasons:

The gearbox control unit, pin 11, has detected a short circuit to the + battery.

The voltage was above 7.5 V.

Notes:

The system switches to the emergency program mode.

When this DTC is generated, the alarm on the instrument cluster lights up.

Elimination:

Check the signal at pin 11 of the electrical connector for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 2912

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Electromagnetic valve of the hydroaccumulator (Y2)

Fault:

Wrong signal from the solenoid valve for the battery retarder.

The reasons:

The control unit transmission, pin 8, found a gap in the wiring.

The voltage was above 4.5 V.

Notes:

No description

Elimination:

Check the signal at pin 8 of the electrical connector for the gearbox control unit. Check the accumulator solenoid valve. Check the connection to earth G504 and electrical connectors according to the wiring diagram for ZF automatic gearbox, see Maintenance and Repair Manual, group 16.

GMS 2913

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Electromagnetic valve of the hydroaccumulator (Y2)

Fault:

Wrong signal from the solenoid valve for the battery retarder.

The reasons:

The gearbox control unit, pin 8, has detected a short to ground.

The voltage was below 19 V.

Notes:

No description

Elimination:

GMS 2914

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Electromagnetic valve of the hydroaccumulator (Y2)

Fault:

Wrong signal from the solenoid valve for the battery retarder.

The reasons:

The gearbox control unit, pin 8, has detected a short circuit to the + battery.

The voltage was above 7.5 V.

Notes:

No description

Elimination:

RET 3000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The system is down.

Elimination:

Replace the control unit.

GMS 3000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect or unreliable data.

The reasons:

Internal malfunction.

Notes:

The system is down.

Elimination:

Replace the control unit.

GMS 4412

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Follower valve D1 (Y20)

Fault:

Wrong signal from the follower valve D1.

The reasons:

The gearbox control unit, pin 57, found a gap in the electrical wiring.

The voltage was above 4.5 V.

Notes:

The system switches to the emergency program mode.

The tracking valve D1 controls the modulation pressure.

Elimination:

Check the signal on the electrical connector pin 57 for the gearbox control unit. Check the follow valve D1 according to the section “Checking the solenoid valves and sensors”.

GMS 4413

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Follower valve D1 (Y20)

Fault:

Wrong signal from the follower valve D1.

The reasons:

The gearbox control unit, pin 57, has detected a short to ground.

The voltage was below 19 V.

Notes:

The system switches to the emergency program mode.

The tracking valve D1 controls the modulation pressure.

Elimination:

Check the signal on the electrical connector pin 57 for the gearbox control unit. Check the follow valve D1 according to the section “Checking the solenoid valves and sensors”.

GMS 4414

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Follower valve D1 (Y20)

Fault:

Wrong signal from the follower valve D1.

The reasons:

The gearbox control unit, pin 57, has detected a short circuit to the + battery.

The voltage was above 7.5 V.

Notes:

The system switches to the emergency program mode.

The tracking valve D1 controls the modulation pressure.

Elimination:

Check the signal on the electrical connector pin 57 for the gearbox control unit. Check the follow valve D1 according to the section “Checking the solenoid valves and sensors”.

GMS 4421

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Follower valve D1

Fault:

Wrong signal from the follower valve D1.

The reasons:

The gearbox control unit, pin 57, found increased resistance in the electrical wiring.

Resistance was below 5 ohms or above 200 ohms.

Notes:

The tracking valve D1 controls the modulation pressure.

The system switches to the emergency program mode.

Elimination:

Check the signal on the electrical connector pin 57 for the gearbox control unit. Check the follow valve D1 according to the section “Checking the solenoid valves and sensors”.

GMS 4512

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Retarder Tracking Valve (Y1)

Fault:

Wrong signal from the retarder servo valve.

The reasons:

The gearbox control unit, pin 6, found a gap in the electrical wiring leading to the retarder follow valve.

The voltage was above 4.5 V.

Notes:

No description

Elimination:

Check the signal at pin 6 of the electrical connector for the gearbox control unit. Check the follow valve. Check the electrical connectors and connections according to the wiring diagram for the ZF automatic gearbox, see the Maintenance and Repair Manual, group 16.

GMS 4513

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Retarder Tracking Valve (Y1)

Fault:

Wrong signal from the retarder servo valve.

The reasons:

The gearbox control unit, pin 6, has detected a short to ground in the wiring to the retarder follow-up valve.

The voltage was below 19 V.

Notes:

No description

Elimination:

GMS 4514

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Retarder Tracking Valve (Y1)

Fault:

Wrong signal from the retarder servo valve.

The reasons:

The gearbox control unit, pin 6, has detected a short circuit to the + battery in the wiring to the follower valve of the retarder.

The voltage was above 7.5 V.

Notes:

No description

Elimination:

GMS 4521

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Retarder Tracking Valve (Y1)

Fault:

Wrong signal from the retarder servo valve.

The reasons:

The gearbox control unit, pin 6, found increased resistance in the electrical wiring leading to the retarder follow-up valve.

Resistance was below 50 ohms or above 600 ohms.

Notes:

No description

Elimination:

GMS 4621

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Mode Selector

Fault:

Wrong signal from mode selector.

The reasons:

No signal in the data line on the CAN bus.

Notes:

Invalid DTC.

Elimination:

Clear the fault code. When re-generating the DTC, replace the gearbox control unit.

GMS 4921

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Fault in the control unit.

Fault:

Internal fault in the gearbox control unit.

The reasons:

Incorrect checksum in the internal memory of the control unit.

Notes:

No description

Elimination:

Clear the fault code. When re-generating the DTC, replace the gearbox control unit.

RET 5000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

The supply voltage from the U30 terminal was above 35 V.

The reasons:

An auxiliary device was probably used for starting up, the voltage of which was too high for a short time. Components or wiring harness may be faulty.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

Elimination:

If an assistive device was used to start, then remove the DTC and check whether it will form again. Also check the alternator, battery, electrical connector, and wiring harness.

GMS 5000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

The supply voltage from the U30 terminal was above 35 V.

The reasons:

An auxiliary trigger device was probably used, the voltage of which was too high for a short time. The components or wiring harnesses may be faulty.

Notes:

The system enters the Locked gear mode, but when the voltage reaches an acceptable value, it returns to its normal driving position. While this fault is active, it does not allow the formation of fault codes for the solenoid valves.

Elimination:

If an assistive device was used to start, then remove the DTC and check whether it will be generated again. If not, check alternator, battery, electrical connector and wiring harness.

RET 5010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Control unit supply voltage too low.

The reasons:

The power at U30 was too low when the engine was running.

Notes:

Braking with a retarder is not possible, and a yellow retarder warning is displayed on the instrument panel.

Elimination:

Also check the alternator, battery, and wiring harness.

GMS 5010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

The supply voltage from the U30 terminal was below 20 V.

The reasons:

Elements or electrical wiring may be defective or loose connection.

Notes:

The system enters Locked gear mode, but when the voltage reaches an acceptable value, it returns to its normal driving position. A malfunction code is generated only when the crankshaft speed exceeds 400 rpm. Therefore, it cannot be generated when starting the engine.

Elimination:

Also check the alternator, battery, connector and wiring harness.

RET 5020

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Incorrect internal reference voltage in control unit.

The reasons:

Electrical fault in the control unit.

Notes:

The pressure and temperature sensor of the retarder is not working reliably.

Elimination:

Clear the fault code.

If this DTC is generated again, replace the control unit.

GMS 5121

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

CAN bus communication

Fault:

Error message or no CAN message.

The reasons:

Possible reasons:

No communication with the gear selector, because the system does not receive a response from the selector.

An error message was sent from the gear selector.

Notes:

No description

Elimination:

Check the wiring for the gear selector.

GMS 5221

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Electrical equipment

Fault:

Faults in the electrical system.

The reasons:

Serious faults in the electrical system.

Notes:

When this DTC is generated, the alarm on the instrument cluster is lit.

Elimination:

Make sure the charging system and battery are in good working condition. Check the electrical connectors and connections according to the wiring diagram for the ZF automatic transmission. See Maintenance and Repair Manual, group 16.

GMS 5521

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

CAN bus data transfer

Fault:

Error message or no CAN message.

The reasons:

Possible reasons:

Communication with the other system has been disabled because the system does not respond.

An error message was sent from another system.

Notes:

No description

Elimination:

Check all the trouble codes in the vehicle because the fault is caused by another system.

GMS 5612

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y19

Fault:

Wrong signal from retarder solenoid valve (Y19).

The reasons:

The gearbox control unit, pin 51, detects a break in the wiring.

The voltage was above 4.5 V.

Notes:

No description

Elimination:

Check the signal on the electrical connector pin 51 for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 5613

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y19

Fault:

Wrong signal from retarder solenoid valve (Y19).

The reasons:

The gearbox control unit, pin 51, detects a short to ground.

The voltage was below 19 V.

Notes:

No description

Elimination:

Check the signal on the electrical connector pin 51 for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 5614

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Solenoid valve Y19

Fault:

Wrong signal from retarder solenoid valve (Y19).

The reasons:

The gearbox control unit, pin 51, detects a short circuit to the + battery.

The voltage was above 7.5 V.

Notes:

No description

Elimination:

Check the signal on the electrical connector pin 51 for the gearbox control unit. Check the solenoid valve according to the “Checking the solenoid valves and sensors” section.

GMS 5818

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Output Shaft Speed Sensor

Fault:

Wrong signal from the output shaft speed sensor.

The reasons:

Exceeded limit value.

Notes:

No description

Elimination:

No description

GMS 5821

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Output Shaft Speed Sensor

Fault:

Wrong signal from the output shaft speed sensor.

The reasons:

The gearbox control unit, pin 16, detects a short to ground. The voltage fell below 0.7 V.
The gearbox control unit, pin 16, detects a short circuit to the + battery. The voltage was above 8 V.
The gearbox control unit, pin 16, detects a break in the wiring. The voltage was above 3.5 V.

Notes:

The system switches to the emergency program mode.

Elimination:

Check the signal at pin 16 of the electrical connector for the gearbox control unit. Check the speed sensor according to the “Checking the solenoid valves and sensors” section.

GMS 5823

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Output Shaft Speed Sensor

Fault:

Wrong signal from the output shaft speed sensor.

The reasons:

Exceeding limit value 2.

Notes:

The system switches to the emergency program mode.

Elimination:

No description

GMS 5918

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Torque converter speed sensor

Fault:

Wrong signal from the torque converter speed sensor.

The reasons:

Exceeded limit value.

Notes:

No description

Elimination:

No description

GMS 5921

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Torque converter speed sensor

Fault:

Wrong signal from the torque converter speed sensor.

The reasons:

The gearbox control unit, pin 62, detects a short to ground. The voltage fell below 0.7 V.
The gearbox control unit, pin 62, detects a short circuit to the + battery. The voltage was above 8 V.
The gearbox control unit, pin 62, detects a break in the wiring. The voltage was above 3.5 V.

Notes:

The system switches to the emergency program mode.

Elimination:

Check the signal at pin 62 of the electrical connector for the gearbox control unit. Check the speed sensor according to the “Checking the solenoid valves and sensors” section.

GMS 5923

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Torque converter speed sensor

Fault:

Wrong signal from the torque converter speed sensor.

The reasons:

Exceeding limit value 2.

Notes:

The system switches to the emergency program mode.

Elimination:

No description

GMS 5945

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Wrong gear ratio in low gear

Fault:

Actual and calculated gear ratios do not correspond to the lowest gear.

The reasons:

It is possible that the malfunction is due to problems in the mechanical system, for example with clutches C1 and C6 for downshifts.

Notes:

Allison DTC: P1739.

The fault code is set when the car is moving in stationary mode, and the calculated calculated gear ratio in lower gear differs from the actual gear ratio.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

Gear shift is not performed.

There are no constant values of the characteristics of the hydraulic system by default.

Procedures for starting or shutting down the engine are not performed.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison dealer.

GMS 6216

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Retarder B16

Fault:

Wrong signal to identify retarder.

The reasons:

The gearbox control unit, pin 49, found that the voltage is higher or higher than 0.7 V.

Notes:

No description

Elimination:

Check the signal at electrical connector pin 49 for the gearbox control unit. Check resistor for retarder B16. Refer to ch. “Check of electromagnetic valves and sensors”.

GMS 6217

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Retarder B16

Fault:

Wrong signal to identify retarder.

The reasons:

The gearbox control unit, pin 49, found that the voltage was below or was below 0.5 V.

Notes:

No description

Elimination:

Check the signal at electrical connector pin 49 for the gearbox control unit. Check resistor for retarder B16. Refer to ch. “Check of electromagnetic valves and sensors”.

GMS 6289

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Accelerator pedal position sensor, low voltage PWM signal

Fault:

The control unit has detected that the PWM signal of the accelerator pedal position sensor was less than 4.9%.

The reasons:

The control unit could select the source of incorrect data on the accelerator pedal position. This code may also be recorded if the harness is damaged.

Notes:

Allison DTC: P1891.

PWM means Pulse Width Modulation.

The control unit has detected a PWM type accelerator pedal sensor.

A fault code is set if the control unit detects that the PWM signal from the accelerator pedal position sensor was less than 4.9% for 5 seconds.

The control unit uses a preselected accelerator pedal position value.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Reboot the control unit using SDP3 or the Allison diagnostic tool and check if the control unit is fixed to the correct source.

Check the wiring harness between the accelerator pedal sensor and pins 12, 44 and 58 of the control unit.

If the fault is not identified, contact your Allison dealer.

GMS 6290

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Accelerator pedal position sensor, high voltage PWM signal

Fault:

The control unit has detected that the PWM signal of the accelerator pedal position sensor was more than 95%.

The reasons:

The control unit could select the source of incorrect data on the accelerator pedal position. This code may also be recorded if the harness is damaged.

Notes:

Allison DTC: P1892.

PWM means Pulse Width Modulation.

The control unit has detected a PWM type accelerator pedal sensor.

A fault code is set if the control unit detects that the PWM signal from the accelerator pedal position sensor has been at more than 95% for 5 seconds.

The control unit uses a preselected accelerator pedal position value.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Reboot the control unit using SDP3 or the Allison diagnostic tool and check if the control unit is fixed to the correct source.

Check the wiring harness between the accelerator pedal sensor and pins 12, 44 and 58 of the control unit.

If the fault is not identified, contact your Allison dealer.

GMS 6319

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Gearbox codes

Fault:

Prohibited codes.

The reasons:

The codes for the gearbox indicate gearshifts without an accelerator, and the gearshift program indicates gearshifts with an accelerator gear, or the codes for the gearbox indicate gearshifts with an accelerator gear.

Notes:

The control unit switches to (maximum) fourth gear.

When this DTC is generated, the alarm on the instrument cluster is lit.

Elimination:

No description

GMS 6418

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Slipping time management

Fault:

Exceeded limit value.

The reasons:

Transmission slips when gear is engaged.

Notes:

When this DTC is generated, the alarm on the instrument cluster lights up.

Elimination:

No description

GMS 6518

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Oil retarder temperature

Fault:

Wrong signal from the oil temperature sensor in the retarder.

The reasons:

The oil temperature in the retarder is higher or higher than 149 ° C.

Notes:

No description

Elimination:

Make sure the transmission cooling system is working properly. Check the electrical connections and wiring according to the wiring diagram for the ZF automatic transmission. See Maintenance and Repair Manual, group 16.

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Control unit outputs

Fault:

Wrong digital signals at the outputs of the control unit.

The reasons:

Short to battery +.

Voltage exceeds 7.5 V

Notes:

No description

Elimination:

Clear the fault code. If the DTC is generated again, check the electrical connectors and wiring of the control unit and the elements according to the wiring diagram for the ZF automatic gearbox. See Maintenance and Repair Manual, group 16.

GMS 6821

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Reinstall the control unit.

Fault:

Incorrect or unreliable data.

The reasons:

No description

Notes:

The system goes into neutral (‘Neutral’).

When this DTC is generated, the alarm on the instrument cluster lights up.

Elimination:

No description

GMS 7624

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Sliding time too long

Fault:

Slip time limit exceeded.

The reasons:

Sliding time between gears 1 and 2 is too long.

Notes:

No description

Elimination:

No description

GMS 7625

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Sliding time too long

Fault:

Slip time limit exceeded.

The reasons:

Sliding time between gears 2 and 3 is too long.

Notes:

No description

Elimination:

No description

GMS 7626

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Sliding time too long

Fault:

Slip time limit exceeded.

The reasons:

Sliding time between gears 3 and 4 is too long.

Notes:

No description

Elimination:

No description

GMS 7627

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Sliding time too long

Fault:

Slip time limit exceeded.

The reasons:

Sliding time between gears 4 and 5 is too long.

Notes:

No description

Elimination:

No description

GMS 7628

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Sliding time too long

Fault:

Slip time limit exceeded.

The reasons:

Too long slip time between gears 5 and 6.

Notes:

No description

Elimination:

No description

GMS 7718

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Engine torque

Fault:

Exceeded limit value.

The reasons:

The torque is greater than the prescribed value.

Notes:

No description

Elimination:

No description

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Check sum

Fault:

Internal malfunction of the control unit.

The reasons:

This information is not reliable.

Notes:

No description

Elimination:

No description

GMS 8580

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Coolant Temperature Sensor (T79) Low Voltage

Fault:

The control unit has determined that the coolant temperature is above the calibrated value.

The reasons:

A possible cause of this fault code may be a short circuit to ground of the wire of contact 35 of the control unit.

Notes:

Allison DTC: P2184.

The fault code is set when the control unit for more than 10 seconds registers the coolant temperature that exceeds the range of calibrated values.

The DTC can only be set if the following conditions are met.

The control unit detects a retarder, an analog engine temperature sensor and a PWM source that requires a retarder.

The function ‘Reducing and pre-selecting a low gear with a retarder based on the temperature of the liquid that cools the engine’ is activated during calibration.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the coolant temperature sensor and pins 58 and 35 of the control unit. If no fault is found, contact your Allison dealer.

GMS 8581

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Coolant temperature sensor (T79), high voltage

Fault:

The control unit has received a coolant temperature value that is less than the specified value.

The reasons:

A possible reason for setting the DTC is an open circuit in one of the wires connected to terminal 35 or 58 of the control unit. Also, the cause of the DTC may be a short circuit to the battery in the wire connected to pin 58.

Notes:

Allison DTC: P2185.

The fault code is set when the control unit registers the coolant temperature below the reference value for more than 10 seconds.

The fault code can be set only when the following conditions are met:

The control unit has detected a retarder, an analog engine temperature sensor and a PWM source that requires a retarder.

When calibrating, the function “Reducing the use of the retarder and the preliminary selection of the retarder transmission on the basis of the engine coolant temperature” is enabled.

The control unit uses the default engine coolant temperature values.

Elimination:

Check the wiring harness between the coolant temperature sensor and pins 58 and 35 of the control unit. If no fault is found, contact your Allison dealer.

GMS 9316

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Follower valve D1

Fault:

Modulation pressure too high.

The reasons:

Track D1 is defective.

Notes:

The DTC is always passive and will be deleted after 10 hours.

Elimination:

Measure the modulation pressure.

If the modulation pressure is higher than 4 +/- 0.3 bar, replace the follower valve D1.

GMS 9318

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Follower valve D1

Fault:

Equalization of pressure by the follow-up valve when shifting to a higher gear is too low.

The reasons:

Exceeded limit value.

Notes:

No description

Elimination:

No description

GMS 9416

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Follower valve D1

Fault:

Modulation pressure too low.

The reasons:

Track D1 is defective.

Notes:

The DTC is always passive and will be deleted after 10 hours.

Elimination:

Measure the modulation pressure.

If the modulation pressure is lower than 4 +/- 0.3 bar, replace the follower valve D1.

GMS 9418

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Follower valve D1

Fault:

Equalization of pressure by the follow-up valve when the load decreases (without opening the throttle valve).

The reasons:

Exceeded limit value.

Notes:

No description

Elimination:

No description

GMS 9516

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Adapt pressure equalization or gear shift.

Fault:

For transmission control units with additional numbers 1532785-1532788, 1780114, 1780115 and 1793537:

Pressure equalization time is too long.

For transmission control units with additional numbers 1768810-1768812, 1779828-1779832 and 1846544:

The maximum permissible adaptation value was reached.

The reasons:

For transmission control units with additional numbers 1532785-1532788, 1780114, 1780115 and 1793537:

Exceeded limit value.

For transmission control units with additional numbers 1768810-1768812, 1779828-1779832 and 1846544:

The maximum allowable value for gear shift adaptation was obtained when shifting gears.

Notes:

No description

Elimination:

No description

GMS 9616

For blocks:

1532785, 1532786, 1532788, 1779828

Title:

Pressure equalization

Fault:

Pressure equalization time is too short.

The reasons:

Exceeded limit value.

Notes:

No description

Elimination:

No description

GMS 9783

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Motor torque limit (SEM) not possible

Fault:

The engine does not respond to a request for torque reduction from the control unit.

The reasons:

One of the possible causes of this fault code may be that the engine does not allow the gearbox control unit to limit torque.

Notes:

Allison DTC: P2637.

This feature is used to accelerate gearshift and achieve near-constant torque, which lowers the temperature and increases the service life of the clutch.

The fault code is set when the control unit detects that the engine is not responding to requests from the control unit to reduce the torque.

The torque limiter function is activated during calibration.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the coolant temperature sensor and pins 58 and 35 of the control unit. If no fault is found, contact your Allison dealer.

GMS 9793

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Motor torque limit (LRTP) not possible

Fault:

The engine does not respond to a request for torque reduction from the control unit.

The reasons:

One of the possible causes of this fault code may be that the engine does not allow the gearbox control unit to limit torque.

Notes:

Allison DTC: P2641.

Turning off the request from the control unit to the torque limiter.

This feature is used to protect the gearbox during slow motion, and when the engine torque exceeds a predetermined value.

The fault code is set when the control unit detects that the engine is not responding to requests from the control unit to reduce the torque.

The torque limiter function is activated during calibration.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 71 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 9833

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Actuator for voltage supply (HSD2) – open circuit

Fault:

Contact an Allison service station.

The reasons:

No description

Notes:

Allison DTC: P2669.

Elimination:

Contact an Allison service station.

GMS 9840

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Voltage Actuator (HSD2) – Low Voltage

Fault:

The control unit has detected a voltage of less than 6 V in the three solenoid valves of the HSD2 circuit.

The reasons:

A possible cause of this fault code may be a short circuit to ground of the wire of the contact 71 of the control unit.

Notes:

Allison DTC: P2670.

The fault code is set when the control unit registers a voltage of less than 6 V on the three solenoid valves in the HSD2 circuit.

The control unit shuts off all solenoid valves.

The DTC can be set when the command to turn on the HSD2 is received.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 71 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 9841

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

High voltage supply voltage control signal (HSD2)

Fault:

The control unit has detected a voltage of more than 6 V in the HSD2 circuit after two solenoid valves have been declared faulty.

The reasons:

A possible reason for the occurrence of this DTC may be an open or short circuit to the positive pole of the contact control unit 71 wire.

Notes:

Allison DTC: P2671.

A malfunction code is issued only if an ON signal has been received on HSD2.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 71 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 9860

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Actuator for voltage supply (HSD3) – open circuit

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P2684.

Elimination:

Contact your Allison dealer.

GMS 9861

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Low voltage power control signal (HSD2)

Fault:

The control unit has detected a voltage of less than 6 V in two solenoid valves in the HSD3 circuit.

The reasons:

A possible cause of this fault code may be a short circuit to ground of the wire of contact 31 of the control unit.

Notes:

Allison DTC: P2685.

A malfunction code is issued only if an ON signal has been received on HSD3.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 31 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 9862

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

High voltage supply voltage control signal (HSD3)

Fault:

The control unit has detected a voltage of more than 6 V in the HSD3 circuit after two solenoid valves have been declared faulty.

The reasons:

A possible cause of this fault code may be an open or short circuit to the positive pole of the contact control unit 31 wire.

Notes:

Allison DTC: P2686.

A malfunction code is issued only if an ON signal has been received on HSD3.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 31 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10,000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Speed sensor

Fault:

Wrong gear ratios.

The reasons:

Elements or electrical wiring may be defective or loose connection. Sensors could be confused during the previous maintenance process. The cause can also be clutch wear.

Notes:

The system enters the “Locked gear” mode.

Elimination:

Check the sensors, connector and wiring harness. Check the clutch.

GMS 10004

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS4 stuck in the disconnected position

Fault:

The control unit has detected a slip in the C4 coupling, the hydraulic pressure in which is provided by the valve PCS2.

The reasons:

The reason may be the following:

An incorrect signal from the turbine shaft or output shaft speed sensor.

Leak or obstruction in supply line C4.

Faulty solenoid PCS4.

Seized control valve for PCS4.

Notes:

Allison DTC: P2714.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

The rotational speed of the output shaft exceeds 125 rpm.

Turbine speed exceeds 60 rpm.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit gives the command to activate the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison dealer.

GMS 10005

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS4 stuck in connected position

Fault:

The PCS4 powers the C4 clutch even when it needs to be turned off. A fault was detected when the control unit determined that the previous transmission had been engaged too long after the shut-off signal had arrived on the clutch.

The reasons:

The reason may be the following:

An incorrect signal from the turbine shaft or output shaft speed sensor.

Obstacle in the release circuit of the clutch C4.

Faulty solenoid PCS4.

Seized control valve for PCS4.

Notes:

Allison DTC: P2715.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

The rotational speed of the output shaft exceeds 125 rpm.

Turbine speed exceeds 60 rpm.

Cold start is not activated.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison dealer.

GMS 10008

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Solenoid valve PCS4, open circuit

Fault:

The control unit has detected an open circuit in the PCS4 reverse circuit.

The reasons:

A possible cause of this fault code may be a break in the wiring of the contact 11 or 55 of the control unit.

Notes:

Allison DTC: P2718.

A fault code is set when the control unit detects an open circuit in the PCS4 return circuit for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and control unit, especially the wires leading to pins 11 and 55 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10009

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS4 solenoid, interference

Fault:

The control unit detected interference in the PCS4 solenoid reverse circuit.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2719.

A fault code is set when the control unit detects a break in the return circuit of the PCS4 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 55 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Speed sensor

Fault:

Speed sensor showed abnormally sharp braking.

The reasons:

Elements or electrical wiring may be defective or loose connection.

Notes:

Unexpected downshift may occur.

Elimination:

Check the sensor, connector and wiring harness.

GMS 10016

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS4 solenoid, short to ground (U31)

Fault:

The control unit has detected a short to ground in the return circuit of the PCS4 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2720.

A fault code is set when the control unit detects a short to ground in the return circuit of the PCS4 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 55 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10017

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS4 solenoid short circuit to battery (U30)

Fault:

The control unit has detected a short circuit to the positive pole in the return circuit of the solenoid valve PCS4.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2721.

A fault code is set when the control unit detects a short to battery in the reverse circuit of the PCS4 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 55 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10019

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS1 solenoid stuck in disconnected position

Fault:

The control unit has detected a slip in the C1 coupling, the hydraulic pressure of which is provided by the valve PCS1.

The reasons:

The reason may be the following:

An incorrect signal from the turbine shaft or output shaft speed sensor.
Leak or obstruction in the supply line C1.
Faulty solenoid PCS1 or SS1.
Seized control valve for PCS1.
Locked shut-off valve for SS1.

Notes:

Allison DTC: P2723.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

The rotational speed of the output shaft exceeds 125 rpm.

Turbine speed exceeds 60 rpm.

Cold start is not activated.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit gives the command to activate the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 10020

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS1 solenoid stuck in connected position

Fault:

The PCS4 powers the clutch C1, even when it has to be turned off. A fault was detected when the control unit determined that the previous transmission had been engaged too long after the shut-off signal had arrived on the clutch.

The reasons:

The reason may be the following:

An incorrect signal from the turbine shaft or output shaft speed sensor.

Obstacle in the circuit for disengaging the clutch C1.

Faulty solenoid PCS1.

Seized control valve for PCS1.

Notes:

Allison DTC: P2724.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The hydraulic system is under pressure.

The frequency of rotation of the output shaft exceeds 200 rpm.

Turbine speed exceeds 200 rpm.

Cold start is not activated.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit attempts to enable the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 10023

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS1 solenoid, open circuit

Fault:

The control unit has detected an open circuit in the reverse circuit of the PCS1 solenoid.

The reasons:

A possible cause of this fault code may be damage to the wiring harness of the circuit of the electrical circuits of the solenoid valve.

Notes:

Allison DTC: P2727.

A fault code is set when the control unit detects an open circuit in the reverse circuit of the PCS1 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wires to terminals 71 and 36 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10024

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS1 solenoid interference

Fault:

The control unit detected interference in the PCS1 solenoid reverse circuit.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2728.

A fault code is set when the control unit detects a break in the return circuit of the PCS1 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 36 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10025

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS1 solenoid, short to ground (U31)

Fault:

The control unit has detected a short to ground in the return circuit of the PCS1 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2729.

A fault code is set when the control unit detects a short to ground in the return circuit of the PCS1 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 36 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10030

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Control block

Fault:

Wrong data.

The reasons:

Incorrect configuration.

Notes:

The system enters the “Locked gear” mode.

Elimination:

Reconfigure the control unit configuration using SDP3. Replace the control unit if that does not work.

GMS 10032

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS1 solenoid, short circuit to battery (U30)

Fault:

The control unit has detected a short circuit to the positive pole in the return circuit of the solenoid valve PCS1.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2730.

A fault code is set when the control unit detects a short to battery in the reverse circuit of the PCS1 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 36 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10038

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS5 solenoid, open circuit

Fault:

The control unit has detected an open circuit in the reverse circuit of the PCS5 solenoid.

The reasons:

A possible cause of this fault code may be damage to the wiring harness of the circuit of the electrical circuits of the solenoid valve.

Notes:

Allison DTC: P2736.

A fault code is set when the control unit detects an open circuit in the reverse circuit of the PCS5 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and control unit, especially the wires leading to pins 31 and 15 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10039

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS5 solenoid interference

Fault:

The control unit detected interference in the PCS5 solenoid reverse circuit.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2737.

A fault code is set when the control unit detects a break in the reverse circuit of the PCS5 solenoid for more than 2 seconds.

The DTC can be set only during the start-up of the control unit, or if the engine speed exceeds 200 rpm.

The control unit allows the inclusion of all gears except the 1st.

Retarder can not be used.

Torque lock is not activated.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 15 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10040

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS5 solenoid short circuit to ground (U31)

Fault:

The control unit has detected a short to ground in the return circuit of the PCS5 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2738.

A fault code is set when the control unit detects a short to ground in the return circuit of the solenoid PCS5 for more than 2 seconds.

The DTC can be set only during the start-up of the control unit, or if the engine speed exceeds 200 rpm.

The control unit allows the inclusion of all gears except the 1st.

Retarder can not be used.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction. Torque lock is not activated.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 15 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10041

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS5 solenoid, short to battery (U30)

Fault:

The control unit has detected a short circuit to the positive pole in the return circuit of the solenoid valve PCS5.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2739.

A fault code is set when the control unit detects a short to battery in the reverse circuit of the PCS5 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

Retarder can not be used.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 15 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10048

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

High oil temperature in the retarder

Fault:

The control unit has determined that the oil temperature in the retarder is above 168 C.

The reasons:

This fault code can be set even if there is no fault. He simply warns that the oil temperature of the retarder has exceeded 168 ° C for at least 10 seconds.

Other possible reasons for setting the DTC:

Prolonged use of the retarder.

Low oil level.

High level of oil.

If the car has a function that allows the simultaneous use of an accelerator and the inclusion of a retarder, for example, for a quick warm-up.

Notes:

Allison DTC: P2740.

The fault code is deleted automatically after 40 startup cycles, during which the fault was not re-detected.

Elimination:

Explore how a car’s retarder is used. If a retarder is used when driving in difficult conditions with a heavy load on long descents, it is likely that this fault code will be set. If there is the slightest suspicion that the gearbox or retarder is faulty, contact your Allison dealer.

GMS 10050

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Retarder oil temperature sensor, low voltage

Fault:

The control unit has received a value for the retarder oil temperature greater than the set value.

The reasons:

One of the possible causes of this fault code may be a short circuit to ground of the wire of contact 75 of the control unit.

Notes:

Allison DTC: P2742.

A fault code is set when the control unit registers the temperature of the retarder oil above the reference value for more than 2.5 seconds.

The control unit uses default oil retarder temperature values.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 75 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10051

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Retarder oil temperature sensor, high voltage

Fault:

The control unit has received a retarder oil temperature value that is less than or equal to the specified value.

The reasons:

This DTC can be set as a result of a break in any of the wires connected to terminal 75 or 58 of the control unit. Also, the cause of this fault code may be a short circuit in the wire connected to the terminal 75 of the control unit.

Notes:

Allison DTC: P2743.

A fault code is set when the control unit registers the temperature of the retarder oil, not exceeding the reference value, for more than 2.5 seconds.

The control unit uses default oil retarder temperature values.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and control unit, especially the wires going to pins 75 and 58 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10081

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Locking solenoid, open circuit

Fault:

The control unit has detected an open circuit in the reverse circuit of the blocking solenoid.

The reasons:

This DTC may also be issued in connection with the breakage of one of the wires going to the contacts 31 or 37 on the control unit.

Notes:

Allison DTC: P2761.

The fault code is set when the control unit detects an open circuit in the reverse circuit of the blocking solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The lock cannot be enabled.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and control unit, especially the wires leading to pins 31 and 37 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10082

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Interlock Solenoid, Interference

Fault:

The control unit has determined the interference in the reverse circuit of the blocking solenoid.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2762.

A fault code is set when the control unit detects a breakdown in the return circuit of the blocking solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The lock cannot be enabled.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 37 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10083

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Blocking solenoid, short circuit to battery (U30)

Fault:

The control unit has detected a short circuit to the positive pole of the return circuit of the lock-up torque converter solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2763.

A fault code is set when the control unit detects a short circuit to the battery in the reverse circuit of the blocking solenoid for more than 2 seconds.

The DTC can be set only during the start-up of the control unit, or if the engine speed exceeds 200 rpm.

Torque lock is not activated.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 37 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10084

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Locking solenoid, short to ground (U31)

Fault:

The control unit has detected a short to ground on the return circuit of the electromagnetic valve that blocks the torque converter.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2764.

A fault code is set when the control unit detects a short to ground in the locking solenoid return circuit for more than 2 seconds.

The DTC can be set only during the start-up of the control unit, or if the engine speed exceeds 200 rpm.

Torque lock is not activated.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to pin 37 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10098

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Failure in reporting low range from transfer case

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P2772.

Elimination:

Contact your Allison dealer.

GMS 10121

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

One or more clutches in the gearbox are worn.

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: P2789.

Elimination:

Contact your Allison dealer.

GMS 10122

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Shift down, incorrect display

Fault:

The control unit has detected an incorrect indication that a forced downshift has been activated.

The reasons:

If the car has a downshift switch connected directly to the control unit (that is, without using a CAN network), the reason for setting this DTC may be damage to the wiring harness or a malfunction of the downshift switch. If the downshift on switch is connected via CAN, the wiring harness between the downshift on switch and coordinator may be damaged.

Notes:

Allison DTC: P278A.

The fault code is set if the accelerator pedal position is less than 20%, and at the same time for more than 5 seconds a reduction in gear is recorded.

The control unit does not allow downshift.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check wiring harness between downshift switch and control unit. The switch is connected to pins 22 and 3 on the control unit. If the downshift switch is connected to the coordinator, check the wiring harness between them. If the fault is not identified, contact your Allison dealer.

GMS 10131

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Information about the position of the selector gear, an incorrect signal PWM

Fault:

The gear selector sent incorrect information to the control unit via the PWM signal.

The reasons:

A possible cause of this fault code may be damage to the wire from the gear selector to contact 34 of the control unit.

Notes:

Allison DTC: P2793.

A fault code is set when the control unit receives incorrect information from the gear selector through a PWM signal.

The control unit ignores the PWM signal from the gear selector.

If a CAN fault is also registered, the control unit locks on the last selected gear.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wire from the gear selector to pin 34 of the control unit. If no fault is found, contact your Allison dealer.

GMS 10248

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS6 solenoid sticking in unused condition (only for 7-speed gearbox)

Fault:

The control unit has detected a slip in the C6 coupling, the hydraulic pressure of which is provided by the valve PCS6.

The reasons:

The reason may be the following:

An incorrect signal from the turbine shaft or output shaft speed sensor.
Leak or obstruction in supply line C6.
Faulty solenoid.
Seized control valve for PCS6.

Notes:

Allison DTC: P2808.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The gearbox must be 7-speed.

The hydraulic system is under pressure.

The rotational speed of the output shaft exceeds 125 rpm.

Turbine speed exceeds 60 rpm.

Cold start is not activated.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit gives the command to activate the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

Contact your Allison transmission dealer.

GMS 10249

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS6 solenoid valve stuck in actuated state (only for 7-speed gearboxes)

Fault:

The PCS6 powers the C6 clutch even when it must be turned off. The control unit has determined that the previous transmission remained engaged for too long after the shut-off signal was applied to the clutch.

The reasons:

The reason may be the following:

An incorrect signal from the turbine shaft or output shaft speed sensor.

Obstacle in the release circuit of the clutch C6.

Faulty solenoid PCS6.

Seized control valve for PCS6.

Notes:

Allison DTC: P2809.

A fault code is set when the control unit detects the following gear ratios for a given number of times.

To set the DTC, the following conditions must be met.

The gearbox must be 7-speed.

The hydraulic system is under pressure.

The frequency of rotation of the output shaft above 200 rpm.

Turbine speed exceeds 200 rpm.

Cold start is not activated.

Torque lock is not activated.

The control unit disables the gearshift adaptation.

The control unit attempts to enable the previous transmission.

While the DTC is active, the control unit does not take into account all the information coming from the gear selector.

The malfunction code is automatically cleared if the vehicle has 40 start cycles without detecting a malfunction.

Elimination:

No description

GMS 10258

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS6 solenoid, open circuit (only for 7-speed gearbox)

Fault:

The control unit has detected an open circuit in the reverse circuit of the PCS6 solenoid.

The reasons:

A possible cause of this fault code may be damage to the wiring harness of the circuit of the electrical circuits of the solenoid valve.

Notes:

Allison DTC: P2812.

A fault code is set when the control unit detects an open circuit in the reverse circuit of the PCS6 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wires leading to pins 11 and 78 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10259

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

PCS6 solenoid, interference (only for 7-speed gearbox)

Fault:

The control unit detected interference in the PCS6 solenoid reverse circuit.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2813.

A fault code is set when the control unit detects a break in the return circuit of the PCS6 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 78 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10260

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Short to ground (U31) in a PCS6 solenoid valve (only for 7-speed gearboxes)

Fault:

The control unit has detected a short to ground in the return circuit of the PCS6 solenoid valve.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2814.

A fault code is set when the control unit detects a short to ground in the return circuit of the PCS6 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 78 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 10261

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Short circuit to positive pole (U30) in solenoid valve PCS6 (only for 7-speed gearbox)

Fault:

The control unit has detected a short circuit to the positive pole in the return circuit of the solenoid valve PCS6.

The reasons:

A possible cause of this fault code may be damage to the harness of the return circuit of the solenoid valve.

Notes:

Allison DTC: P2815.

A fault code is set when the control unit detects a short to battery in the reverse circuit of the PCS6 solenoid valve for more than 2 seconds.

The DTC can be set only during the start of the control unit, or at a rotational speed of the engine crankshaft of more than 200 rpm.

The control unit shuts off all solenoid valves.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the wiring harness between the gearbox and the control unit, especially the wire leading to terminal 78 on the control unit. If the fault is not identified, contact your Allison dealer.

GMS 11000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Engine management

Fault:

The problem in the management of the engine when shifting gears.

The reasons:

Malfunction in shift control or malfunction in engine control unit.

Notes:

The system is included in “Clutch mode” (“Clutch mode”). The system has a confirmation of the neutral position even on the condition that the gear is engaged. Instead of increasing the engine speed when the gearbox is in the neutral position, when shifting to a lower gear with the clutch released, this causes the car to move forward. When the car accelerates even when the accelerator pedal is released, the inconvenience may be felt. After approximately three seconds, the OPC system stops controlling the engine, the vehicle stops accelerating, and a fault code is generated.

Elimination:

Check the gearshift and engine control unit.

GMS 11010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Moment

Fault:

The difference between the required torque and the torque read from the engine is too great.

The reasons:

The EMS management module may be faulty.

Notes:

The system is included in “Clutch mode” (“Clutch mode”).

Elimination:

Check whether the EMS control unit generated any trouble codes. Check whether the EMS control unit has the correct spare part number.

GMS 11020

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Gear selector position

Fault:

Invalid combination from gear selector.

The reasons:

Components or wiring may be faulty, shorted, or loose.

Notes:

The system keeps the last approved position. The coordinator reads the position of the shift lever and transmits the current position information to the OPC control unit. Valid positions: reverse gear, neutral position, manual mode and automatic mode. The OPC control unit expects only one position at a time. The only approved case in which more than one position is indicated is when the manual and automatic modes are activated. In this case, the manual mode is applied. In all other cases of having more than one position, a fault code will be generated.

Elimination:

Check the gear selector, coordinator, electrical connector and wire harness.

GMS 11030

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Accelerator pedal position

Fault:

Incorrect or unreliable data.

The reasons:

Elements or electrical wiring may be defective or loose connection.

Notes:

The system receives a kick-down confirmation, even if the accelerator pedal is not fully depressed.

Elimination:

Check if the coordinator generated any trouble codes. Check downshift switch, electrical connector and wiring harness.

GMS 11040

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN data transfer from engine control unit

Fault:

According to the message TC1 received Time Out.

The reasons:

Elements or electrical wiring may be defective or loose connection. If fault codes 11040, 11041, 11050, 11051 and 11060 were generated, there may be a break in the CAN bus circuit that goes to the GMS control unit.

Notes:

This may result in poor performance for the OPC feature.

Elimination:

Check CAN bus connections, connectors, and wiring harness. Also check the engine control unit.

GMS 11041

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN data transfer from engine control unit

Fault:

According to the message TC1 received Time Out.

The reasons:

If TC1 is expected and this message is not received within a certain period of time, a fault code is generated.

Notes:

The system is included in “Clutch mode” (“Clutch mode”).

Elimination:

Check CAN bus connections, connectors, and wiring harness. Also check the engine control unit.

GMS 11045

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Unexpected reaction from the engine

Fault:

The engine’s crankshaft speed does not fall fast enough even with the condition that during the gear shift process the OPC system requested from the engine management system the inclusion of the engine retarder.

The reasons:

Elements or electrical wiring may be defective or loose connection.

Notes:

Gear shifting, usually performed with the engine retarder activated, becomes slower. These gear shifts are, for example, gear shifts when the accelerator pedal is in the kickdown position or gear shifts when moving up. The uphill will be complicated, and the engine’s rotational speed, at which the gearbox is shifted to a higher gear when going uphill, will be higher than usual.

Elimination:

Check the trouble codes in the engine management system. Check the engine retarder, including its electrical connectors and wiring harness.

GMS 11050

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN data transfer from coordinator

Fault:

According to the message TC1 received Time Out.

The reasons:

If TC1 is expected and this message is not received within a certain period of time, a fault code is generated.

Notes:

This may result in poor performance for the OPC feature.

Elimination:

Check CAN bus connections, connectors, and wiring harness. Also check the coordinator.

GMS 11051

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Gear Lever Position

Fault:

According to the message TC1 received Time Out.

The reasons:

If the TC is expected and this message is not received within a certain period of time, a fault code is generated.

Notes:

The system enters the “Locked gear” mode.

Elimination:

Check CAN bus connections, connectors, and wiring harness. Also check the coordinator.

GMS 11060

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Data transfer via CAN bus from BMS

Fault:

According to the BMS received Time Out.

The reasons:

This DTC is generated if one of the CAN messages expected from BMS disappears or is missing.

Notes:

The TC1 message disappears, resulting in poor performance. For example, with slippery road surfaces, the drive wheels can lose tractive effort, which causes the gearbox to shift to a higher gear without any increase in vehicle speed.

Elimination:

Check CAN bus connections, connectors, and wiring harness. Also check the brake control unit.

GMS 12000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Transmission Oil Temperature Sensor

Fault:

Too high voltage between ground and electrical circuit.

The reasons:

An open or short to power terminal 30 in the electrical circuit of the transmission oil temperature sensor.

Notes:

The temperature sensor on the gearbox is optional equipment (optional). The configuration of the control unit is not designed for the presence of a temperature sensor transmission, as a standard element.

Elimination:

Check the sensor, connector and wiring harness. Also check the configuration of the control unit.

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Bms

Fault:

Incorrect or unreliable data.

The reasons:

The control unit does not receive or receives incorrect speed signals from the BMS, or the configuration of the gear ratio of the main gear or the radius of the wheels is incorrectly configured. If fault codes 32CB, 332F, or 3390 were also generated, the problem is probably a mechanical failure of the Opticruise system.

Notes:

This speed is used for comparison purposes to ensure that the OPC and TCO speed sensors supply the correct information. If these speed signals are correct, the system is not affected. In the event of a permanent malfunction of the engine speed sensor, the OPC system enters “Locked gear” mode.

Elimination:

Check the sensor, connector and wiring harness.

check for the DTCs generated for the BMS brake system; also check the configuration of the main gear and the configuration of the radius of the wheels in the OPC.

If there is also a DTC 65415, check for DTCs for AWD.

If fault codes 32CB, 332F or 3390 have been generated, perform a check of the mechanical elements of the gearbox. Make sure that the washer and neutral spring are properly installed and there is no jamming of the splines on the longitudinal lever and / or the shaft of the actuator.

GMS 14000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Cross left

Fault:

There is no confirmation of the move.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

The requested transfer is not supported or not confirmed by the system. A fault code is not generated on a stationary vehicle. It is generated when the actual time spent on the gear shift exceeds the specified time.

Elimination:

Check the sensor, solenoid valve, pneumatic cylinder, electrical connector and wiring harness. Check the gear shift mechanism.

GMS 14001

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Cross left

Fault:

Loss of confirmation of the lateral course to the left.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

The system maintains the current gear position.

Elimination:

Check the sensor, connector and wiring harness. Check the gear shift mechanism.

GMS 14010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Cross way to the right

Fault:

There is no confirmation of the move.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

Elimination:

Check the sensor, solenoid valve, pneumatic cylinder, electrical connector and wiring harness. Check the gear shift mechanism.

GMS 14011

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Cross way to the right

Fault:

Loss of lateral confirmation to the right.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

The system maintains the current gear position.

Elimination:

Check the sensor, connector and wiring harness. Check the gear shift mechanism.

GMS 14020

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Longitudinal advance

Fault:

There is no confirmation of the move.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

Elimination:

Check the sensor, solenoid valve, pneumatic cylinder, electrical connector and wiring harness. Check the gear shift mechanism.

GMS 14021

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Longitudinal advance

Fault:

Loss of confirmation of longitudinal advance.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

The system maintains the current gear position.

Elimination:

Check the sensor, connector and wiring harness. Check the gear shift mechanism.

GMS 14030

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Longitudinal backward

Fault:

There is no confirmation of the move.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

Elimination:

Check the sensor, solenoid valve, pneumatic cylinder, electrical connector and wiring harness. Check the gear shift mechanism.

GMS 14031

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Longitudinal backward

Fault:

Loss of longitudinal backward confirmation.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

The system maintains the current gear position.

Elimination:

Check the sensor, connector and wiring harness. Check the gear shift mechanism.

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Top row of the multiplicator

Fault:

There is no confirmation of the move.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

Elimination:

Check the sensor, solenoid valve, pneumatic cylinder, electrical connector and wiring harness. Check the gear shift mechanism.

GMS 14051

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Top row of the multiplicator

Fault:

Loss of confirmation.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

The system maintains the current gear position.

Elimination:

Check the sensor, connector and wiring harness. Check the gear shift mechanism.

GMS 14060

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Lower Range Range

Fault:

There is no confirmation of the move.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

Elimination:

Check the sensor, solenoid valve, pneumatic cylinder, electrical connector and wiring harness. Check the gear shift mechanism.

GMS 14061

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Lower Range Range

Fault:

Loss of confirmation.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

The system maintains the current gear position.

Elimination:

Check the sensor, connector and wiring harness. Check the gear shift mechanism.

The following information applies to buses with a range damper: make sure that the range damper is not filled with oil.

GMS 14070

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Upper level divider

Fault:

There is no confirmation of the move.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

On overdrive transmissions (GRSO), the divider solenoid valves are controlled differently than direct transmissions (GRS). When switching to the upper divider level, the solenoid valve of the lower divider stage is activated, and when switching to the lower divider stage, the solenoid valve of the upper divider stage is activated.

Elimination:

Check the sensor, solenoid valve, pneumatic cylinder, electrical connector and wiring harness. Check the gear shift mechanism.

GMS 14071

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Upper level divider

Fault:

Loss of confirmation.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

A fault code will be generated if, for example, the transmission suddenly shuts down.

Notes:

The system maintains the current gear position.

Elimination:

Check the sensor, connector and wiring harness. Perform a mechanical check of the gearshift or gearbox.

GMS 14080

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Bottom divider

Fault:

There is no confirmation of the move.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

Notes:

Elimination:

Check the sensor, solenoid valve, pneumatic cylinder, electrical connector and wiring harness. Check the gear shift mechanism.

GMS 14081

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Bottom divider

Fault:

Loss of confirmation.

The reasons:

Elements or electrical wiring may be defective or loose connection. A mechanical fault may have occurred.

A fault code will be generated if, for example, the transmission suddenly shuts down.

Notes:

The system maintains the current gear position.

Elimination:

Check the sensor, connector and wiring harness. Check the gear shift mechanism.

GMS 14100

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Hall Sensor

Fault:

Simultaneous confirmation from the position sensors “left side” and “right side”, which is not plausible.

The reasons:

Components or cable harness may be faulty or shorted.

Notes:

The system saves the current gear and locks to neutral when first attempting to switch.

Elimination:

Check the sensors, connector and wiring harness.

GMS 14101

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Hall Sensor

Fault:

Simultaneous confirmation from the position sensors “forward” and “backward”, which is not plausible.

The reasons:

Components or cable harness may be faulty or shorted.

Notes:

The system saves the current gear and locks to neutral when first attempting to switch.

Elimination:

Check the sensors, connector and wiring harness.

GMS 14102

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Hall Sensor

Fault:

Simultaneous confirmation from the position sensors “forward” and “neutral position”, which is not plausible.

The reasons:

Components or cable harness may be faulty or shorted.

Notes:

The system saves the current gear and locks to neutral when first attempting to switch.

Elimination:

Check the sensors, connector and wiring harness.

GMS 14103

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Hall Sensor

Fault:

Simultaneous confirmation from the position sensors “back” and “neutral position”, which is not plausible.

The reasons:

Components or cable harness may be faulty or shorted.

Notes:

The system saves the current gear and locks to neutral when first attempting to switch.

Elimination:

Check the sensors, connector and wiring harness.

GMS 14104

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Confirmation switch

Fault:

Simultaneous confirmation from the position of the sensors of the “top row” and “bottom row”, which is not believable.

The reasons:

Components or cable harness may be faulty or shorted.

Notes:

The system saves the current gear and locks to neutral when first attempting to switch.

Elimination:

Check the sensors, connector and wiring harness.

GMS 14105

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Confirmation switch

Fault:

Simultaneous confirmation from the position sensors of the “upper divider stage” and “lower divider stage”, which is not plausible.

The reasons:

Components or cable harness may be faulty or shorted.

Notes:

The system saves the current gear and locks to neutral when first attempting to switch.

Elimination:

Check the sensors, connector and wiring harness.

GMS 14150

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Output voltage to the acknowledgment connector and Hall sensors.

Fault:

Voltage too high between terminal 30 and electrical circuit.

The reasons:

The Hall sensor and / or the divider confirmation switch and / or the amplifier sensors have a short to ground.

Notes:

Lost information about the current transfer. No gear shift possible. The system saves the current gear and locks to neutral when first attempting to switch. The generation of a DTC relative to the current transfer is stopped.

Elimination:

Check the sensor, connector and wiring harness.

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Solenoid valve upper stage divider

Fault:

Too high voltage between ground and electrical circuit.

The reasons:

An open circuit or short circuit to the power terminal 30 in the electrical circuit of the solenoid valve.

Notes:

A short to power terminal 30 activates the solenoid valve. An open circuit means the solenoid valve cannot be activated.

In gearboxes with accelerating gear (GRSO), the solenoid valves of the divider are controlled in a different way, not in the same way as in gearboxes with direct gear (GRS). When switching to the upper divider stage, the solenoid valve of the lower divider stage is activated; when switching to the lower stage of the divider, the solenoid valve of the upper stage is activated.

Elimination:

Check the solenoid valve, connector and wiring harness.

GMS 17071

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Solenoid valve upper stage divider

Fault:

Voltage between ground and electrical circuit too low.

The reasons:

A short to ground in the electrical circuit of the solenoid valve.

Notes:

Solenoid valve cannot be activated.

Elimination:

Check the solenoid valve, connector and wiring harness.

GMS 17080

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Solenoid valve lower stage divider

Fault:

Too high voltage between ground and electrical circuit.

The reasons:

An open circuit or short circuit to the power terminal 30 in the electrical circuit of the solenoid valve.

Notes:

A short to power terminal 30 activates the solenoid valve. An open circuit means the solenoid valve cannot be activated.

Elimination:

Check the solenoid valve, connector and wiring harness.

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Hydraulic pressure

Fault:

Oil pressure is high even without a request for braking torque.

The reasons:

Oil pressure is high even without a request for braking torque.

Notes:

When the brake pedal is pressed, the retarder does not brake in the EBS system, and the green retarder lamp does not light up on the instrument panel.

Elimination:

Check the pressure sensor, connectors, wiring harness, solenoid valves, and follow-up valve.

RET 21000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN data transfer from engine control unit

Fault:

Exceeded time limit from engine.

The reasons:

This DTC is generated if one or all of the CAN messages expected from the engine control unit are missing.

Notes:

Depending on which messages or messages are not on the CAN bus, the retarder will work with a braking torque limit.

Functions that may be affected: There is no joint operation of the brake systems, retarder braking with the help of the lever does not turn off during acceleration, the engine brake does not work in conjunction with the retarder.

Elimination:

Check CAN bus connections, connectors, and wiring harness. Also check the engine control unit.

The generation of fault codes 5212 and 521C may be caused by a break in the CAN bus going to the GMS control unit.

RET 21010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN data transfer from coordinator

Fault:

Excess time limit from the coordinator.

The reasons:

This DTC is generated if one or all CAN messages expected from the coordinator are missing.

Notes:

Depending on which messages or messages are not on the CAN bus, the retarder will work with a braking torque limit.

In the worst case, retarder braking will be impossible.

Elimination:

Check CAN bus connections, connectors, and wiring harness. Also check the coordinator.

The generation of DTCs 5208 and 521C may be caused by a break in the CAN bus going to the GMS control unit.

RET 21020

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Data transfer via CAN bus from BMS

Fault:

Exceeded time limit (Time Out) from the brake system.

The reasons:

This DTC is generated if one or all of the CAN messages expected from the brake control unit are missing.

Notes:

Braking is permitted only with the use of a hand lever. Retarder will not turn off when you press the accelerator pedal. The retarder is turned off only when the hand lever returns to its upper position.

Elimination:

Check CAN bus connections, connectors, and wiring harness. Also check the brake control unit.

The generation of DTCs 5208 and 5212 can be caused by a break in the CAN bus going to the GMS control unit.

RET 21030

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Coolant temperature sensor

Fault:

Implausible temperature response from the sensor.

The reasons:

The cause may be too little oil in the retarder, or air leakage in the retarder or in the supply hoses. This causes a decrease in braking force, and as a result, the temperature reaction is insufficient compared with the expected temperature response.

Contacts between the wiring harness and the temperature sensor may be oxidized. Oxidation changes the resistance of the circuit, which leads to a significant distortion of the temperature values in a big way.

Temperature sensor may be faulty. It may give incorrect temperature values or not react at all to temperature changes, for example, show a constant temperature value regardless of its changes.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

If this DTC is generated, the retarder will not work until the control unit is restarted.

Elimination:

Check the amount of oil in the retarder and air leaks.

Clean the oxide film from the sensor connections and connectors. If the above operations did not help, then you need to replace the temperature sensor.

RET 21040

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Retarder oil temperature sensor

Fault:

Implausible temperature response from the sensor.

The reasons:

Temperature sensor may be faulty. It may give incorrect temperature values or not react at all to temperature changes, for example, show a constant temperature value regardless of its changes.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

If this DTC is generated, the retarder will not work until the control unit is restarted.

Elimination:

Check the amount of oil in the retarder and air leaks.

Clean the oxide film from the sensor connections and connectors. If the above operations did not help, then you need to replace the temperature sensor.

GMS 21266

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Sensor for retarder request, abnormally low voltage

Fault:

Abnormally low voltage on the sensor to query the retarder.

The reasons:

The cause of the fault may be as follows:

Damaged wiring harness.
Incorrectly connected sensor.
The sensor is faulty.
Failed module that sends requests to the retarder.
Faulty control unit.

Notes:

Allison DTC: C1312.

This DTC is issued when the control unit determines that the request signal voltage to the retarder was below 0.3 V for 5 seconds.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check the wiring harness between the sensor and pins 56 and 12 of the control unit. If no fault is found, contact your Allison dealer.

GMS 21267

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Sensor for retarder request, abnormally high voltage

Fault:

Abnormally high voltage on the sensor to request a retarder.

The reasons:

The cause of the fault may be as follows:

Damaged wiring harness.

Incorrectly connected sensor.

The sensor is faulty.

Failed module that sends requests to the retarder.

Faulty control unit.

Notes:

Allison DTC: C1313.

This DTC is issued when the control unit determines that the request signal voltage to the retarder was above 4.7 V for 5 seconds.

The malfunction code is reset automatically if 40 vehicle start cycles have been completed without detecting this malfunction.

Elimination:

Check the wiring harness between the sensor and pins 56 and 12 of the control unit. If no fault is found, contact your Allison dealer.

RET 22000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Coolant temperature sensor

Fault:

The voltage between the ground and the electrical circuit is too high.

The reasons:

An open or short to power terminal 30 in the temperature sensor circuit.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

If this DTC is generated, the retarder will not work until the control unit is restarted.

Elimination:

Check the temperature sensor, connector and wiring harness.

RET 22001

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Coolant temperature sensor

Fault:

The voltage between the ground and the electrical circuit is too high.

The reasons:

A short to ground on the temperature sensor circuit.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

If this DTC is generated, the retarder will not work until the control unit is restarted.

Elimination:

Check the temperature sensor, connector and wiring harness.

RET 22010

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Oil temperature sensor

Fault:

The voltage between the ground and the electrical circuit is too high.

The reasons:

An open circuit or short circuit to + battery in the temperature sensor electrical circuit.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

If this DTC is generated, the retarder will not work until the control unit is restarted.

Elimination:

Check the temperature sensor, connector and wiring harness.

RET 22011

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Oil temperature sensor

Fault:

The voltage between the ground and the electrical circuit is too high.

The reasons:

A short to ground on the temperature sensor circuit.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

If this DTC is generated, the retarder will not work until the control unit is restarted.

Elimination:

Check the temperature sensor, connector and wiring harness.

RET 24000

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Hydraulic pressure

Fault:

The voltage between the ground and the electrical circuit is too high.

The reasons:

Oil pressure too low or short to ground in oil pressure sensor circuit.

Notes:

When the brake pedal is pressed, the retarder does not brake in the EBS system, and the green retarder lamp does not light up on the instrument panel.

Elimination:

Check the oil level, gauge, connector and wiring harness.

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Electromagnetic valve accumulator.

Fault:

Open circuit of the solenoid valve of the hydroaccumulator.

Possible short circuit on + battery in retarder 1.

The reasons:

Open circuit of the solenoid valve of the hydroaccumulator.

Possible short circuit on + battery in retarder 1.

Notes:

The retarder works, but turning it on takes more time.

Elimination:

Check the solenoid valve, connector and wiring harness.

RET 27011

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Electromagnetic valve accumulator.

Fault:

Short circuit to earth of the solenoid valve of the accumulator.

The reasons:

Short circuit to earth of the solenoid valve of the accumulator.

Notes:

The retarder works, but turning it on takes more time.

Elimination:

Check the solenoid valve, connector and wiring harness.

RET 27100

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Tracking valve

Fault:

Short to battery + in the watchdog circuit.

The reasons:

Short to battery + in the watchdog circuit.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

If this DTC is generated, the retarder will not work until the control unit is restarted.

Elimination:

Check valve, connector and wiring harness.

RET 27101

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Tracking valve

Fault:

Open the follower valve circuit.

Possible short circuit on + battery in retarder 1.

The reasons:

Open the follower valve circuit.

Possible short circuit on + battery in retarder 1.

Notes:

No retarder braking is possible. The yellow indicator on the instrument cluster is on.

If this DTC is generated, the retarder will not work until the control unit is restarted.

Elimination:

Check valve, connector and wiring harness.

GMS 49153

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

CAN2 communication problems

Fault:

This DTC cannot be registered in the control unit installed on the Scania vehicle.

The reasons:

A possible reason for the issuance of this DTC is a calibration error.

Notes:

Allison DTC: U0001.

Elimination:

Contact your Allison transmission dealer.

GMS 49168

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

CAN1 communication problems (J1939)

Fault:

The control unit has detected a disconnection on the CAN bus.

The reasons:

A possible cause of this fault code may be a malfunction in the CAN bus or the control unit connected to it.

Notes:

Allison DTC: U0010

The fault code is set when the control unit registers the absence of CAN communication for more than 3 seconds.

Motor torque limit (SEM) is not possible.

The control unit returns to the last saved gear shift adaptation and uses the default values of the accelerator pedal position.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the health of the CAN bus to which the control unit is connected. Check whether other control units connected to the same CAN bus can communicate on this bus.

GMS 49408

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Disconnection with engine management system (J1587).

Fault:

This DTC cannot be registered in the control unit installed on the Scania vehicle.

The reasons:

A possible reason for the issuance of this DTC is a calibration error.

Notes:

Allison DTC: U0100.

Elimination:

Contact your Allison transmission dealer.

GMS 49411

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Open connection with gear selector 1

Fault:

The control unit has not received data from the primary gear selector for a specified period of time.

The reasons:

Possible reasons for setting this DTC:

Bad contact or damaged cable harness between the gear selector and the coordinator.
Damaged gear selector.
If the car has an Allison gear selector, there may be a problem with connecting via CAN or powering the gear selector.

Notes:

Allison DTC: U0103.

A fault code is set if the control unit does not receive periodic heartbeats from the main gear selector for at least 2 seconds.

If the Allison gear selector is used, the gear shift range is selected using PWM signals.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Check the gear selector and wiring harness between the gear selector and the coordinator. Check the CAN bus and power connections with the Allison gear selector installed.

GMS 49429

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Disconnection with engine management system (J1939).

Fault:

The control unit has not received from the engine control unit data on the engine torque or the position of the accelerator pedal for a certain period of time.

The reasons:

A possible reason for the occurrence of this DTC may be a malfunction of the engine control unit or in the places of its connection to the CAN bus.

Notes:

Allison DTC: U0115.

A fault code is set if the control unit does not receive information about the engine torque or the position of the accelerator pedal from the engine control unit for more than 2 seconds.

The control unit returns to the last saved gear shift adaptation and uses the default values of the accelerator pedal position.

The control unit disables gear shift adaptation.

Elimination:

Make sure that the engine control unit is in good condition and there are no faults in the CAN bus.

GMS 49809

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Open communication with gear selector 2

Fault:

The control unit has not received data from the secondary gear selector for a certain period of time.

The reasons:

Causes of failure may be as follows:

Bad contact or damage to the wiring harness between the gear selector and the coordinator.
Damaged gear selector.
Problems connecting to the CAN bus or power supply selector gear.

Notes:

Allison DTC: U0291.

This DTC is issued when the control unit does not receive a clock pulse from the optional gear selector for at least 2 seconds.

If the Allison gear selector switch is used, the gear shift range is determined using PWM signals.

Elimination:

Check the CAN bus and power connections to the secondary gear selector.

GMS 49924

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Incompatible main gear selector

Fault:

The installed gear selector is not an Allison J1939 model selector or is not a selector approved by the manufacturer.

The reasons:

A possible cause of this DTC may be the use of an inappropriate gear selector or an incorrect setting of the control unit.

Notes:

Allison DTC: U0304.

A fault code is set if the gear selector detects that the selector is not an Allison J1939 selector or an approved OEM gear selector.

The control unit ignores information from the gear selector.

The control unit disables gear shift adaptation.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Contact your Allison transmission dealer.

GMS 49971

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Incompatible additional gear selector

Fault:

The installed gear selector is not an Allison J1939 model selector or is not a selector approved by the manufacturer.

The reasons:

A possible cause of this DTC may be the use of an inappropriate gear selector or an incorrect setting of the control unit.

Notes:

Allison DTC: U0333.

A fault code is set if the gear selector detects that the selector is not an Allison J1939 selector or an approved OEM gear selector.

The control unit ignores information from the gear selector.

The control unit disables gear shift adaptation. The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Contact your Allison transmission dealer.

GMS 50176

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Incorrect communication data received

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: U0400.

Elimination:

Contact your Allison dealer.

GMS 50177

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Incorrect data received from engine management system via CAN2

Fault:

This DTC cannot be registered in the control unit installed on the Scania vehicle.

The reasons:

No description

Notes:

Allison DTC: U0401.

Elimination:

Contact your Allison dealer.

GMS 50180

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Incorrect data from the main gear selector

Fault:

The control unit has detected the arrival of incorrect data from the main gear selector.

The reasons:

Possible cause: gear selector faulty.

Notes:

Allison DTC: U0404.

A fault code is set if the control unit detects incorrect data from the main gear selector.

If the Allison gear selector is used, the gear shift range is selected using PWM signals.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Contact your Allison transmission dealer.

GMS 50242

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Incorrect data received from engine management system via CAN1

Fault:

Contact your Allison dealer.

The reasons:

No description

Notes:

Allison DTC: U0442

Elimination:

Contact your Allison dealer.

GMS 50578

For blocks:

1761440, 1761450, 1847996, 2025050

Title:

Incorrect data with additional gear selector

Fault:

The control unit has detected the arrival of incorrect data from an additional gear selector.

The reasons:

Possible cause: gear selector faulty.

Notes:

Allison DTC: U0592.

A fault code is set if the control unit detects incorrect data from the auxiliary shift selector.

If the Allison gear selector is used, the gear shift range is selected using the optional PWM signal.

The fault code is deleted automatically if the car has gone through 40 startup cycles, during which the fault was not registered again.

Elimination:

Contact your Allison transmission dealer.

RET 65410

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN message for engine speed from EMS.

Fault:

Incorrect or unreliable data.

The reasons:

This DTC is secondary and is caused by another DTC.

Notes:

It can be generated in both OPC and RET. If a fault code is generated in the retarder, the maximum torque of the retarder is limited and the engine brake does not work while the speed control function is running during descent. If a malfunction code is generated in OPC, then for each gear change, you will need to use a clutch, although the system is not in Clutch mode.

Elimination:

Check the trouble codes in the engine control unit.

GMS 65410

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN message for engine speed from EMS.

Fault:

Incorrect or unreliable data.

The reasons:

This DTC is secondary and is caused by another DTC.

Notes:

It can be generated in both OPC and RET. If a fault code is generated in the retarder, the retarder is not activated. If a malfunction code is generated in OPC, then for each gear change, you will need to use a clutch, although the system is not in Clutch mode.

Elimination:

Check the trouble codes in the engine control unit.

RET 65411

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN message for cardan shaft rotation speed from TCO.

Fault:

Incorrect or unreliable data.

The reasons:

This DTC is secondary and is caused by another DTC.

Notes:

If a malfunction occurs in the retarder and the vehicle is not equipped with the Opticruise system, the activation of the retarder is impossible. A fault code can be generated in both OPC and RET.

Elimination:

Check the trouble codes in the coordinator.

GMS 65411

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN message for cardan shaft rotation speed from TCO.

Fault:

Incorrect or unreliable data.

The reasons:

This DTC is secondary and is caused by another DTC.

Notes:

If a fault occurs in the retarder and the car is not equipped with an Opticruise switch, then the retarder cannot be switched on. A fault code can be generated in both OPC and RET.

Elimination:

Check the trouble codes in the coordinator.

RET 65412

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

Wheel speed message sent over CAN bus

Fault:

Incorrect or unreliable data.

The reasons:

Incorrect or unreliable data.

Notes:

Deterioration in gear shift comfort.

Elimination:

Check the fault codes in the brake system.

GMS 65412

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN message for front axle speed from BMS.

Fault:

Incorrect or unreliable data.

The reasons:

This DTC is secondary and is caused by another DTC.

Notes:

There was some deterioration in the logic of gear shifting, especially on slippery roads, there was some decrease in comfort in gear shifting.

Elimination:

Check for DTCs in BMS.

RET 65500

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN message for ABS is fully functional.

Fault:

If the ABS system is fully operational, there should be no indication of a malfunction or access should be via the CAN bus.

The reasons:

A fully functional ABS system indicates a malfunction or is not available via the CAN bus.

Notes:

Impaired functioning of the retarder: Only braking with a hand lever is permitted. Retarder will not turn off when you press the accelerator pedal. The retarder is turned off only when the hand lever returns to its upper position.

Elimination:

Check for DTCs in BMS.

GMS 65500

For blocks:

1548413, 1724590, 1757823, 1763365

Title:

CAN message for fully functional ABS system.

Fault:

A fully functional ABS system indicates a malfunction or is not available via the CAN bus.

The reasons:

No description

Notes:

RET: Functionality degraded. Braking is permitted only with the use of a hand lever. Retarder will not turn off when you press the accelerator pedal. The retarder is turned off only when the hand lever returns to its upper position.

Elimination:

Check for DTCs in BMS.