Air Bag Control Module: Description and Operation

Diagnostic Monitor
The diagnostic monitor assembly contains a microcomputer that monitors the electrical system components and connections. The monitor performs a self-check of the microcomputer internal circuits and energizes the system readiness indicator lamp during prove out and whenever a fault occurs. System electrical faults can be detected and translated into coded warning indicator displays. If certain faults occur, the system will be disarmed by a firing disarm device built into the monitor. If a system fault exists and the warning indicator is malfunctioning, an audible tone will be heard indicating the need for service.

System Readiness Indicator
The system readiness indicator is an instrument cluster-mounted indicator that will momentarily light whenever the ignition switch is turned from OFF to RUN if the air bag system is working properly. If the system is not functioning properly, the indicator will either fail to light, stay on continuously or light in a flashing mode (if a system fault exists and the indicator is malfunctioning an audible tone will be heard indicating the need for service). If a fault occurs after the prove out the indicator will light either continuously or in a coded flashing mode.

Tone Generator
The air bag readiness indicator is the prime means of determining the air bag system condition. However, a series of five sets of five tones will be heard if the readiness indicator is out and a fault occurs in the system. This also means that the Supplemental Driver Air Bag System is in need of service. The tone pattern will repeat periodically until the fault and indicator are serviced. Unless serviced, the Supplemental Driver Air Bag Restraint System may not function properly in the event of an accident.