Body Control Module (BCM)

The BCM is responsible for gating messages across the various bus networks.
The BCM is responsible for actuating the low side of starter relay once commanded by the PCM high side relay CRANK command.
The BCM communicates over the Local Interface Network (LIN) bus with the Intelligent Battery Sensor (IBS) information about raw battery current, voltage, and temperature levels
The BCM is responsible for deactivating the starter motor relay driver.