Ignition Switch Lock Cylinder: Description and Operation

The Ignition lock cylinder is located at the upper right side of the steering column. The Passlock TM sensor is in the steering column and is separate from the key and lock cylinder. However, both work together to determine if the proper ignition key was used to start the vehicle.

In the event of an open Class 2 serial data line between the BCM and the PCM / VCM the vehicle will become fail-enabled if the PCM / VCM has already received the password from the BCM for that ignition cycle (i.e. the engine is running). In this event, the Security telltale will be ON continuously and the PCM / VCM will become fail-enabled for future ignition cycles. If a failure in the Class 2 serial data line occurs before the ignition cycle, when the PCM / VCM is not fail-enabled, the PCM / VCM will never receive a valid password to enable the fuel injectors and the vehicle will not start.