Circuit/System Description

When certain control modules are programmed and configured during installation, the module learns a special immobilizer code that is unique to the car. The immobilizer code is used to prevent modules from being switched between different vehicles. The Body Control Module (BCM) contains the immobilizer code. The instrument cluster, Electronic Brake Control Module (EBCM) and HVAC control module learn the immobilizer code during the configuration process. When the car is used, these units compare their immobilizer codes against the BCM. If the codes match, the car is allowed to start. If an immobilizer code does not match, the car cannot be started.