Section 17 (Body Control Modules): Description

WARNING: This page is about a different car, the 2000 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Deactivate air bag system before performing any service operation. See appropriate AIR BAG RESTRAINT SYSTEMS article. Do not apply electrical power to any component on steering column without first deactivating air bag system. Air bag may deploy.

The Body Control Module (BCM) communicates with the following systems over the serial data line to control various functions.

Powertrain Control Module (PCM)
Instrument Panel Cluster (IPC)
Real Time Damping (RTD)
Seat Control Module (SCM)
Left Door Control Module (LDCM)
Right Door Control Module (RDCM)
Remote Function Actuator (RFA)
Heating, Ventilation & Air Conditioning (HVAC)
Radio
Anti-lock Brake System (ABS)
Supplemental Inflatable Restraint (SIR)

Some vehicle systems share data 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 and sends power mode messages on the serial data line. Power mode messages are ignition switch position. Systems not directly communicating with the ignition switch use the power mode messages to determine ignition switch position. Systems other than the BCM respond to the power mode messages with a State Of Health (SOH) code message. The SOH messages lets the BCM know that those systems can communicate with other systems.