Air Bag Systems: Description and Operation

SYSTEM OPERATION
Airbag Control Module (ACM)
The Airbag Control Module (ACM) contains the impact sensor and energy reserve capacitor. The ACM monitors the system to determine the system readiness. The ACM contains on-board diagnostics and will light the AIRBAG warning lamp in the message center when a problem occurs.

The driver and passenger airbag system is a safety device designed to reduce the risk of fatality or serious injury, caused by a frontal impact of the vehicle.

The impact sensor provides verification of the direction and severity of the impact. One impact sensor is used. It is located inside the Airbag Control Module (ACM) which is mounted on a bracket, just forward of the center console. The impact sensor is an accelerometer that senses deceleration. The deceleration pulses are sent to a microprocessor which contains a decision algorithm. When an impact is severe enough to require airbag protection, the ACM micro processor sends a signal that completes the electrical circuit to the driver and passenger airbags. The sensor is calibrated for the specific vehicle and reacts to the severity and direction of the impact.

Clockspring
The clockspring is snapped into a plastic mounting platform on the steering column behind the steering wheel. The clockspring is used to maintain a continuous electrical circuit between the wiring harness and the driver's airbag module. This assembly consists of a flat ribbon like electrically conductive tape which winds and unwinds with the steering wheel rotation.

Airbag Module Locations:

Driver And Passenger Airbag Modules
The Driver Airbag Module is located in the center of the steering wheel. The Passenger Airbag Module is located in the instrument panel above the glove box. The Driver Airbag Module cover contains the horn switch, inflator device, and a fabric bag. The airbag cover/horn switch is serviced separately from the inflator and bag components. The Passenger Airbag Module is serviced as an assembly.

WARNING: WHEN THE AIRBAG SYSTEM IS DEPLOYED BECAUSE OF A COLLISION, THE FOLLOWING MUST BE REPLACE:
- COMPLETE STEERING COLUMN ASSEMBLY
- LOWER STEERING COUPLER
- STEERING WHEEL
- STEERING COLUMN CLOCKSPRING
- DRIVER AIRBAG COVER/HORN SWITCH
- DRIVER AIRBAG MODULE
- PASSENGER AIRBAG MODULE
- UPPER INSTRUMENT PANEL WITH PAD.