Section 6 (Body Control Modules): Description

WARNING: This page is about a different car, the 1999 Pontiac Grand Am and 1999 Oldsmobile Alero. However, it is still accessible from the selected car via links, so may be relevant.

The Body Control Module (BCM) controls many functions of the vehicle. These functions include A/C compressor request, A/C condenser fan, interior and exterior lighting, battery rundown protection, audible warnings (chime), instrument panel cluster indicators and gauges, electric door locks, low tire pressure monitor, and theft deterrent.

The BCM communicates with other systems over a serial data line to execute various vehicle functions. Communication between each system is accomplished by sending digitally coded messages, which consist of specific information the system module must follow. Each system module is assigned its own recognition code, so that it can respond to appropriate messages. The BCM acts as the power mode master, which can determine State Of Health (SOH) of other systems.

Other modules that communicate with the BCM over this line are the Electronic Brake Control Module (EBCM), Powertrain Control Module (PCM), Instrument Panel Cluster (IPC) and the remote control door lock receiver.