Operation CHARM: Car repair manuals for everyone.

Powertrain Control Module (PCM)

The PCM communicates with the BCM over the Class 2 serial data line. When the BCM determines an incorrect password, it sends a Class 2 serial data password to the PCM in order to disable the crank relay and fuel injection system. If the BCM receives the expected voltage from the PASSLOCK sensor, the BCM sends a class 2 serial data password to the PCM in order to enable the crank relay and fuel injection system. The PCM then allows the vehicle to start normally.