Starting the engine

When an ignition key is inserted in the ignition switch the immobilizer control module transmits a code to the transponder, which responds with its own encrypted code. This code is decrypted in the immobilizer control module and is compared to the learned codes in the control module. Key validation takes a maximum of 300 ms. If the codes correspond the immobilizer control module begins communicating with the engine control module (ECM). This communication is encrypted and only permits communication between two units, the immobilizer control module and the engine control module (ECM), where the engine control module (ECM) continuously monitors the communication.

After the key has been validated and the engine started, a question-answer routine checks regularly that the key is still in place.

If the communication between the immobilizer control module and the engine control module (ECM) should stop while the car is driving, after cable breakage for example, the engine will continue to run. When the engine stops the engine control module (ECM) will go to the blocked position and the engine cannot be restarted.

If for some reason the engine should stall, due to incorrect gear selection uphill for example, communication is not re-established even if the ignition is switched on and off again within 4 minutes.