Impact Sensor: Description and Operation

WARNING: Do not attempt to diagnose or troubleshoot air bag circuitry without proper information. Improper troubleshooting could cause the air bags to fire inadvertently, causing injury.

The Air Bag Restraint System consists of a driver air bag, an Air Bag Diagnostic Module and Crash Sensors.

Air Bag Diagnostic Module

The Air Bag Diagnostic Module contains a microcomputer that monitors electrical system components and connections. The assembly performs a self-check of the microcomputer's internal circuits and energizes the Air Bag Indicator lamp during prove out and whenever a fault occurs. Twenty different faults can be detected and translated into a coded lamp display. If certain faults occur, the system will be disarmed by a firing disarm device built into the monitor assembly. If a system fault exists and the lamp is malfunctioning, an audible tome will be heard, indicating the need for service.

Sensors

The sensor assembly is an electrical switch which reacts to impacts according to direction and force. It discriminates between impacts that require air bag inflation and impacts that do not require air bag inflation. When an impact occurs that requires air bag inflation, the sensor contacts close, completing the electrical circuit: the system then operates.

Five crashes sensors are mounted in the vehicle. At least two sensors. One safing, one forward must be activated to inflate the air bag.