Description And Operation: Operation

The seat belt tensioners are deployed in conjunction with the dual front airbags by signals generated by the Occupant Restraint Controller (ORC) through the individual driver or passenger retractor (or sill end), tensioner (or anchor) line 1 and line 2 (or squib) circuits. When the ORC sends the proper electrical signal to the tensioner initiators, the electrical energy generates enough heat to initiate a small pyrotechnic Micro Gas Generator (MGG).

In sequence, the ORC activates the retractor tensioner, followed by the anchor tensioner. The retractor tensioner MGG drives the seat belt retractor spool causing slack to be removed from the front seat belt. The anchor tensioner gas generator pulls the anchor rod and seat belt webbing eyelet downward, causing the slack to be removed from the front seat belt.

Removing excess slack from the front seat belts not only keeps the occupants properly positioned for an airbag deployment following a frontal impact of the vehicle, but also helps to reduce injuries that the occupants of the front seats might experience in these situations as a result of harmful contact with the steering wheel, steering column, instrument panel or windshield. The front seat belt retractors also have a pyrotechnic-type load limiter consisting of a spring-loaded disc with multiple teeth on both sides. The teeth will engage in and out of the closest fitting grooves as the disc rotates. Milliseconds after a crash has occurred, seatbelt webbing is gradually released after the crash reducing any rebound effect, further reducing the potential for injuries.

The ORC monitors the condition of the seat belt tensioners and adaptive load limiters through circuit resistance. If any fault is detected the ORC will illuminate the airbag indicator in the instrument cluster and store a Diagnostic Trouble Code (DTC). Proper diagnosis of the seat belt tensioner and adaptive load limiter initiators and squib circuits requires the use of a diagnostic scan tool and may also require the use of the Airbag Kit. Refer to the appropriate diagnostic information.