DTC 3 ECM Communication Error: General Description
The immobilizer system consists of a mutual authentication transponder inside the key head, a stand alone antenna, the BCM unit and the EMS. The BCM unit shall emulate the original immobilizer to EMS protocol as closely as possible.
In the Stand alone immobilizer system, the immobilizer is contained within the BCM. The EMS shall request the BCM for permission to start the vehicle. The BCM shall perform the immobilization functions and reply "start" or no start permission to the EMS.
The communication between the BCM and EMS for the purposes of immobilization for the stand alone will be via the "W Line".