Passlock Theft Deterrent System

This vehicle is equipped with the Passlock theft deterrent system. This system contains a Passlock sensor. The Passlock sensor is part of the ignition lock cylinder assembly. The Body Control Module (BCM) interfaces with the Passlock sensor.

When turning the ignition switch to the START position with the proper key, the Passlock sensor generates an analog voltage signal, which is sent to the BCM. This analog voltage signal is of a specific value to the vehicle and varies from vehicle to vehicle. When attempting to start the engine, the BCM compares a preset stored analog voltage value with the signal coming from the sensor. Because both values match, the BCM sends a fuel enable password via the Class 2 Serial Data Line to the Powertrain Control Module (PCM). As a result, the PCM enables the crank relay, and allows fuel delivery to the engine.

When attempting to start the engine by means other than using the proper key in the ignition switch, the Passlock sensor sends a analog voltage signal of a different value. The BCM compares the preset stored analog voltage value with the signal coming from the sensor. Because both values do not match, the BCM sends a fuel disable password via the Class 2 Serial Data Line to the Powertrain Control Module (PCM). As a result, the PCM disables the crank relay, and does not allow fuel delivery to the engine.