Diagnostic Functions

Diagnostic functions

General
The central electronic module (CEM) is the master unit for the immobilizer. The central electronic module (CEM) also directly stores diagnostic trouble codes (DTCs) for faults in the immobilizer system. Some other faults can also be stored in the engine control module (ECM).
For information about diagnostic functions, see Design and Function, central electronic module (CEM), and Design and Function, engine control module (ECM).

Programming
To increase the security of the immobilizer system, the central electronic module (CEM) and the engine control module (ECM) are linked to each other with codes. The codes must be programmed if a control module is replaced before the vehicle can be started. Programming replaced control modules takes place automatically when downloading software into the new control module.

Programming ignition keys
Ignition keys can be added and erased. A maximum of 6 key IDs can be programmed into the central electronic module (CEM). When programming a key, the key is identified to the control module with a code that is stored in the control module memory.
When a key is programmed for the vehicle, the remote control code is also entered if this is to be linked to the vehicle. However, the remote control code has nothing to do with the immobilizer system. For further information, see Design and Function, central locking.
If a new key is added to a vehicle, the transponder in the key for this vehicle is locked and consequently cannot be programmed for another vehicle.
The erase function is used when the customer wishes to prevent one or more keys from being used to start the vehicle. The keys may have been stolen and could be traced back to the vehicle.

Note! The following applies for model year 2004: Ignition keys and remote controls are integrated. Therefore the code for the remote control and the transponder must be available when programming. These are programmed at the same time. This means that a key that has been erased can be programmed back into the same vehicle if both these keys are available. The codes are on the packaging in which the keys are supplied. If the codes are not available, a new ignition key must be ordered.

Keys are programmed via VIDA vehicle communication.