ECM (Engine Control Module)
- The ECM (PCM) (A) carries out a check of the ignition key using a special encryption algorithm, which is programmed into the transponder as well as the ECM simultaneously. Only if the results are equal, the engine can be started. The data of all transponders, which are valid for the vehicle, are stored in the ECM.
ERN (Encrypted Random Number) value between EMS and encrypted Immobilizer unit is checked and the validity of coded key is decided by EMS.