Checking Drive Authorization

When the transmitter key (A8/1) in the electronic ignition / starter switch control module (N73) is turned to position 2, the engine control module is supplied with voltage. After a secret data exchange between the engine control module and the electronic ignition / starter switch control module (N73), the drive authorization code is computed in parallel in the two control modules. These two calculations are then compared in the engine control module. If verification is successful, the start authorization is issued. If no start authorization is issued, this is stored in the fault memory of the engine control module. If the start authorization is given, the transmitter key receives an appropriate message via infrared from the electronic ignition / starter switch control module (N73).