Operation

OPERATION

FRONT AIRBAG SYSTEM

The front airbag system electrical circuits are continuously monitored by a microprocessor and software contained within the Occupant Restraint Controller (ORC). The ORC also contains impact sensing elements, which are monitored by the ORC to determine when an impact occurs that is severe enough to require front airbag system protection. When a frontal impact is severe enough, the ORC initiates the inflator units of both front airbags to deploy.

An airbag indicator lamp in the instrument cluster lights for six to eight seconds as a bulb test each time the ignition switch is turned to the ON position. Following the bulb test, the airbag indicator lamp is turned ON or OFF by the ORC to indicate the status of the airbag system. If the airbag indicator lamp comes ON at any time other than during the bulb test, it indicates that there is a problem in the airbag system. Such a problem may cause the airbags not to deploy when required, or to deploy when not required.

During a frontal vehicle impact, the knee blockers work in conjunction with properly adjusted seat belts to restrain the driver and front seat passenger in the proper position for an airbag deployment. The knee blockers also work to absorb and distribute the crash energy from the driver and front seat passenger to the structure of the instrument panel. The driver side knee blocker is integral to the lower instrument panel bezel. The passenger side knee blocker is integral to the glove box door. If equipped with a knee blocker airbag, the airbag will inflate in the event of a frontal impact when the ORC determines that the impact is severe enough to fire the second stage of the rest of the front airbags. The CCN will illuminate the seat belt indicator if either the driver or passenger seat belts are not buckled. The driver seat belt switch is hard wired to the CCN. The passenger seat belt switch is sent via a CAN data bus message to the ORC and then to the CCN. If the passenger seat belt is not buckled, the passenger OCS will not have the CCN indicator illuminate. The switches are integral to the retractors.

SIDE IMPACT AIRBAG SYSTEM

The ORC controls the seat back mounted airbags (one left and one right). If a ORC determines the impact is severe enough, based upon a signal from the Satellite Acceleration Sensor (SAS), the ORC will send a signal and the appropriate airbag will inflate, tearing open the front seat back trim cover protecting the occupants. Once a seat back mounted airbag has been deployed, the entire seat back as well as any damaged parts must be replaced.

BELT TENSIONER SYSTEM

At the onset of an impact event, each tensioner uses a pyrotechnic device which is triggered simultaneously with the airbags to rapidly retract the seat belts. With the slack removed, the occupant's forward motion in an impact will be reduced as will the likelihood of contacting interior components.

WARNING: When the front airbag is deployed, the tensioner will have deployed also, and must be replaced.

The ORC monitors the seat belt tensioner circuit and reports active and stored Diagnostic Trouble Codes (DTC's) if any problem is found.

Once a vehicle has been in an accident, the tensioner will have a Gravel/Grinding sound to it after the tensioner has been put into use. This must be replaced along with any deployed airbags and broken or damaged parts.