Key identification and start procedure

The following procedure takes place after inserting the vehicle key in the ignition lock:

• The transponder in the key is powered via the loop antenna and sends the key data to the CAS control module.
• The CAS control module checks the key data to ensure it is correct and only then sends an enable signal to the starter.
• The CAS control module sends the variable code to DME/DDE. There, the variable code is checked against the saved variable code; if they match, the fuel injection is released.
• After the engine has started, the CAS control module generates new key data (change code) and transfers them to the transponder in the key.
• A new variable code is also created and stored in the DME/DDE control module.