Airbag System Components
CLOCKSPRINGThe clockspring is screwed to a plastic mounting platform on the steering column behind the steering wheel. The clockspring is used to maintain a continuous electrical circuit between the wiring harness and the drivers airbag.
This assembly consists of a flat ribbon like electrically conductive tape which winds and unwinds with the steering wheel rotation. The clockspring cannot be repaired. If the clockspring is faulty, damaged, or if the airbag has been deployed, the clockspring must be replaced.
DRIVER AIRBAG
The Driver Airbag is located in the center of the steering wheel. The most visible part of the airbag is the cover/horn switch.
The Driver Airbag 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.
When the front airbag system is deployed, the following MUST be replaced:
- Complete Steering Column Assembly.
- Lower Steering Column Coupler.
- Steering Wheel.
- Clock Spring.
- Driver Airbag
- Passenger Airbag
- Upper Instrument Panel with Pad.
Care Of Undeployed Airbags
Airbags must be stored in their original special container until used for service. At no time should a source of electricity be permitted near the inflator on the back of an airbag. When carrying or handling an undeployed airbag, the trim side of the airbag should be pointing away from the body to minimize possibility of injury if accidental deployment occurs. Do not place undeployed airbag face down on a solid surface, the airbag will propel into the air if accidental deployment occurs.
OCCUPANT RESTRAINT CONTROLLER
The front driver and passenger airbag system is designed to reduce the risk of fatality or serious injury, caused by a frontal impact of the vehicle.
The Occupant Restraint Controller (ORC) contains the impact sensor and energy reserve capacitor. It is mounted on a bracket, under the instrument panel, just forward of the storage bin. The ORC monitors the system to determine the system readiness. The ORC contains on-board diagnostics and will light the AIRBAG warning lamp in the message center when a problem occurs.
The impact sensor provides verification of the direction and severity of the impact. One impact sensor is used. It is located inside the Occupant Restraint Controller (ORC). The impact sensor is an accelerometer that senses deceleration. The deceleration pulses are sent to a microprocessor which contains a decision algorithm. When an impact is severe enough to require airbag protection, the ORC microprocessor sends a signal that completes the electrical circuit to the driver and passenger airbags. The impact sensor is calibrated for the specific vehicle and reacts to the severity and direction of an impact.
PASSENGER AIRBAG
WARNING: NEVER DISASSEMBLE THE PASSENGER AIRBAG, THE PASSENGER AIRBAG HAS NO SERVICEABLE PARTS.
The Passenger Airbag is located beneath the instrument panel and pad assembly. The airbag is mounted to the back side of the instrument panel reinforcement.
The instrument panel top pad is the most visible part of the passenger airbag system. Located under the instrument panel top pad are the airbag door, the passenger airbag cushion and the airbag cushion supporting components.
The passenger airbag includes a magnesium housing within which the cushion and inflator are mounted and sealed.
Following a passenger airbag deployment, the passenger airbag and the instrument panel must be replaced. The passenger airbag cannot be repaired, and must be replaced if deployed or damaged in any way.
The passenger airbag is equipped with two inflators, each with three levels of pressure output. The inflators seal the hole in the airbag cushion so it can discharge the gas it produces directly into the cushion when supplied with the proper electrical signal. Following an airbag deployment, the airbag cushion quickly deflates by venting this gas through the cushion material towards the instrument panel.
The passenger airbag is secured with screws to the instrument panel beneath the instrument panel top pad and above the glove box opening. The instrument panel top pad above the glove box opening conceals the airbag door and a predetermined hinge line beneath its decorative cover. Upon airbag deployment, the top pad will bend at the hinge line and the door will fold back out of the way onto the top of the instrument panel.
When the front airbag system is deployed, the following MUST be replaced:
- Complete Steering Column Assembly.
- Lower Steering Column Coupler.
- Steering Wheel.
- Clock Spring.
- Driver Airbag.
- Passenger Airbag.
- Upper Instrument Panel with Pad.
Care Of Undeployed Airbags
Airbags must be stored in their original special container until used for service. At no time should a source of electricity be permitted near the inflator on the back of an airbag. When carrying or handling an undeployed airbag, the trim side of the airbag should be pointing away from the body to minimize possibility of injury if accidental deployment occurs. Do not place undeployed airbag face down on a solid surface, the airbag will propel into the air if accidental deployment occurs.
SEAT AIRBAG
The side impact airbag system Seat Airbags are located in the outboard side of the front seat backs.
Fig.1 Seat Airbag - Typical:
One in each front seat. The seat airbag inflator assembly is within the airbag housing. Each airbag is mounted to the seat back frame. If deployed or defective, the entire seat back assembly must be replaced.
Only the Side Impact Airbag Control Module (SIACM) can deploy the side airbags. When supplied with the proper electrical signal, the seat airbag inflator will produce a gas and discharge the bag directly between the occupant and the side of the vehicle, protecting the occupant Upon deployment, the seat back trim cover will tear open and allow the side airbag to fully inflate and quickly deflate.
SEAT BELT TENSIONER
The seat belt system incorporates Seat Belt Tensioners The tensioner is designed to hold the occupant in their respective seat by retracting the seat belt up to four inches. They are integral to the front seat belt buckles and cannot be serviced. If found defective they must be replaced. After an airbag deployment, the tensioner must be replaced.
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. After an impact that deploys the airbags, the seat belt tensioner assembly must be replaced.
The Occupant Restraint Controller (ORC) monitors the seat belt tensioner circuit resistance 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 must be replaced along with any deployed airbags and broken or damaged parts. Refer to the proper Body Diagnostic Procedures manual for diagnosis and testing.
WARNING: WHEN THE FRONT AIRBAG IS DEPLOYED, THE TENSIONER WILL HAVE DEPLOYED ALSO AND SHOULD BE REPLACED.
SIDE IMPACT AIRBAG CONTROL MODULE
The side airbag system is a safety devise designed to reduce the risk of fatality or serious injury caused by a side impact of the vehicle.
Vehicles equipped with side impact airbags use two Side Impact Airbag Control Modules (SIACM). One is located on each respective side body B-pillar. Each contains an impact sensor that senses a side impact occurrence. The SIACM communicates with the ORC via the PCI bus in order to notify the driver of any potential side airbag system problem.
The impact sensor provides verification of the direction and severity of the side impact. The right side SIACM controls the right seat airbag. The left side SIACM controls the left seat airbag. In the event of a side impact the appropriate SIACM will send an electronic signal to its airbag, deploying the airbag. The SIACM communicates with the Occupant Restraint Controller (ORC) via the PCI bus circuit.
The accelerometer pulses are sent to a microprocessor, which contains a decision algorithm. When an impact is severe enough to require airbag protection, the SIACM microprocessor sends a signal to deploy the side airbag that completes the electrical circuits to the right or left side airbag. The sensor is calibrated for the specific vehicle and reacts to the severity and direction of the impact.