Body Control Module: Description and Operation
BODY CONTROL MODULEThe PASS-Key(R) system is an internal function of the Body Control Module (BCM). The BCM reads the key code from the ignition cylinder when the ignition is turned to the ON position. If the code is correct, the BCM will send an enable message to the PCM via the class 2 serial data circuit. If the BCM receives the wrong code, the BCM will immediately go into tamper mode. The BCM will send a disable message to the PCM disabling the starting and fuel delivery systems.