Introduction

Fig. 1 Airbag Restraint System:

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. 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 is an electronically-triggered system that used only its own internal electronic sensor to trigger the airbags. The JA and JX Bodies used only the AECM system.

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 deflation of the airbag is 1/10th of a second.

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

COMPONENTS

The major components of the SRS are;

- The Airbag Module
- The Clockspring
- The Impact Sensors
- The Airbag System Diagnostic Module (ASDM or PASDM).

If any of these parts should fail, they must be replaced, as they cannot be repaired.

NOTE: Use the test procedures in Testing & Inspection to find the cause of any customer complaint regarding the "Air Bag" warning lamp.

GLOSSARY OF TERMS USED
Active Codes: A malfunction that is present now.

ACM: Airbag Control Module (also called the Air Bag System Diagnostic Module (ASDM)).

ASDM: Air Bag System Diagnostic Module (also called the Airbag Control Module (ACM)).

Air Bag Module: Also called "Squib" initiator - located inside the air bag module assembly.

Impact Sensor: G force sensitive, threshold switches which close when an impact of sufficient force in the correct direction occurs.

An impact switch closure accompanied by closure of the safing sensor, alerts the control module that it is now time to deploy the airbag(s).

Initiator: Also called "Squib" - located inside the air bag module assembly.

PASDM: Passenger Air Bag System Diagnostic Module

Safing Sensor: A switch inside the ASDM which must be closed at the same time at least one of the impact sensors is closed, to initiate deployment of the airbag(s).

Squib: Also called "Air Bag Module" initiator - located inside the air bag module assembly.

SRS: Supplemental Restraint System

Stored Codes: A malfunction that had been present during a previous key cycle, may or may not be active.