Air Bag Systems: Description and Operation

AIRBAG SYSTEM
The airbag system is designed to provide increased driver and passenger protection if the vehicle is involved in a front end collision. The system is most effective when used in conjunction with the seat belt system.

Both driver and passenger side airbag assemblies are now hybrid type which utilize a canister of compressed, inert gas to inflate the bag, instead of sodium azide.

Airbag Module Locations:

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. Refer to Horns for proper service procedure for horn switch. The Passenger Airbag Module is serviced as an assembly.

Currently, Chrysler Corporation uses two types of Airbag Control Modules. The ASDM system is a mechanically-triggered system utilizing two front impact sensors and a sensor inside the module. The AECM (AB, AS, JA and NS bodies only) is an electronically-triggered system that uses only its own internal electronic sensor to trigger the airbags. This information will address the AECM type of module. The term "Airbag Control Module" (or ACM) will be used to refer to the module.

Functional Operation
Whenever the ignition key is turned to the RUN or START position, the Airbag Control Module (ACM) performs a lamp check by turning the AIRBAG warning lamp ON. The lamp stays lit for 6 to 8 seconds, then goes off. If the lamp remains OFF, it means that the ACM has checked the system and found it to be free of discernible malfunctions. The airbag system is monitored by the ACM.

The ACM monitors critical input and output circuits within the airbag system, making sure they are operating correctly. Some circuits are tested continuously; others are checked only under certain circumstances. The ACM provides diagnostic information about the airbag system to the technician through the DRB via the CCD bus.

The deceleration or g-force resulting from the impact of a front-end collision causes the electronic sensor inside of the ACM to be triggered. This causes the inflators to be actuated, thus deploying the airbags. The total time between determining to deploy and full inflation of the airbag is approximately 40ms.

A new enhanced accident response feature has been added. This feature, upon deployment of the airbag, turns on the interior lights and unlocks the power door locks (if equipped).

The AIRBAG warning lamp is the only point at which "symptoms" of a system malfunction can be observed by the customer.

Use the test procedures to find the cause of any customer complaint regarding the AIRBAG warning lamp, such as:
- warning lamp does not come on at all
- warning lamp stays on

WARNING: WHEN THE AIR BAG SYSTEM IS DEPLOYED BECAUSE OF A COLLISION, THE FOLLOWING MUST BE REPLACED:
- 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