Impact Sensor: Description and Operation

Crash Sensors

WARNING: VEHICLE SENSOR ORIENTATION IS CRITICAL FOR PROPER SYSTEM OPERATION. IF A VEHICLE EQUIPPED WITH AN AIR BAG SYSTEM HAS BEEN INVOLVED IN A CRASH WHERE THE FENDERS OR GRILLE AREA HAVE BEEN DAMAGED, INSPECT THE SENSOR MOUNTING BRACKETS FOR DEFORMATION. IF DAMAGED, THE SENSOR SHOULD BE REPLACED WHETHER OR NOT THE AIR BAG IS DEPLOYED. IN ADDITION, ENSURE THAT THE BODY STRUCTURE IN THE AREA OF THE SENSOR MOUNTING IS RESTORED TO ITS ORIGINAL CONDITION.

The three crash sensors are located at the front of the vehicle along the body chassis. Two crash sensors are located beneath the front fenders on the right and left unibody front bumper supports. The third crash sensor is located on the radiator support.





The crash sensors each consist of:
- a sensing mass
- a bias magnet
- a cylindrical tube
- two electrical contacts





During normal operation, the bias magnet holds the sensing mass in place against the magnet. The two electrical contacts remain open during normal operation. Upon impact, the sensing mass pulls away from the bias magnet and rolls down the tube toward the electrical contacts. When the sensing mass hits the electrical contacts, it completes the air bag deployment crash circuit.

When the circuit is completed, it grounds the ignitor in the air bag module and the air bag is deployed.

NOTE: At least one crash sensor and the safing sensor must be activated simultaneously to inflate the air bag.

Unless the crash sensor is damaged during impact, the sensing mass returns to its original position after making contact.