Air Bag Control Module: Description and Operation

Diagnostic Monitor
The diagnostic monitor contains a microprocessor that monitors the electrical system components and connections. The monitor performs a self-check of the microprocessor internal circuits and energizes the system readiness indicator during prove out and whenever a fault occurs. System electrical faults can be detected and translated into different coded indicator displays. If certain faults occur, the microprocessor will disable the system by opening a thermal fuse built into the monitor. If a system fault exists and the indicator is malfunctioning, an audible tone will be heard signaling the need for service.

An air bag system backup power supply is included in the diagnostic monitor to provide air bag deployment power if the battery or battery cables are damaged in an accident before the crash sensors close. The power supply will deplete its stored energy approximately one minute after the positive cable of the battery is disconnected.

WARNING: THE BACKUP POWER SUPPLY ENERGY MUST BE DEPLETED BEFORE ANY AIR BAG COMPONENT SERVICE IS PERFORMED. TO DEPLETE THE BACKUP POWER SUPPLY ENERGY, DISCONNECT THE POSITIVE BATTERY CABLE AND WAIT ONE MINUTE.