Body Control Module (BCM)
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
The BCM is a class 2 device. It communicates with the engine control module (ECM)/powertrain control module (PCM) and the instrument panel cluster for EPM operation. The BCM determines the output of the generator and sends the information to the ECM/PCM for control of the generator field control circuit. It monitors the generator field duty cycle signal circuit information sent from the ECM/PCM for control of the generator. It monitors a battery current sensor, the battery positive voltage circuit, and estimated battery temperature to determine battery SOC. The BCM performs idle boost and load management operations.