Body Control Module (BCM)

The body control module (BCM) is a GMLAN device. It communicates with the engine control module (ECM) and the instrument panel cluster for electrical power management (electrical power management) operation. The BCM determines the output of the alternator and sends the information to the ECM for control of the alternator turn on signal circuit. It monitors the alternator field duty cycle signal circuit information sent from the ECM for control of the alternator. It monitors a battery current sensor, the battery positive voltage circuit, and estimated battery temperature to determine battery state of charge. BCM requests an idle increase depending on the battery's charge state.