The immobiliser system includes PCM / ECM and SMARTRA3 units, as well as ignition keys with a built-in transponder.
The PCM / ECM checks the ignition key using a special encryption algorithm with SMARTRA3 and a transponder.
The encryption algorithm (between PCM / ECM and SMARTRA3) has been developed by BOSCH.
The encryption algorithm (between the PCM/ECM and the transponder) is of the Hitag 2 type, which is used by high-level systems. When the ignition is switched on, the PCM/ECM performs SMARTRA3 authentication and then key authentication. The engine can be started after the key authentication has been confirmed by the SMARTRA3.
The key programming process is initiated by the PCM / ECM with a PIN code request from the scanner. A ‘clean’ PCM / ECM will store the PIN and then proceed to register the keys. The registered PCM / ECM compares the PIN code received from the scanner with the vehicle password stored in the transponder. If the data is correct, the key registration process begins.
The scanner asks for permission to register the first key and the PCM / ECM registers first the SMARTRA3 and then the first key. If the SMARTRA3 is already registered and the PIN is different, the SMARTRA3 returns the wrong PIN to the PCM / ECM. In this case the PCM / ECM cannot register any keys.
DESCRIPTION OF DIAGNOSTIC FAULT CODE
If there is an incorrect response from the transponder, the PCM / ECM will register code P1693.
