Seat Air Bag - Operation

OPERATION

Each Seat AirBag (SAB) (also known as a pelvic and thoracic airbag) is deployed individually by an electrical signal generated by the Occupant Restraint Controller (ORC) to which it is connected through left or right SAB line 1 and line 2 (or squib) circuits. The hybrid-type inflator assembly for each SAB contains a small canister of highly compressed inert gas. When the ORC sends the proper electrical signal to the SAB inflator, the electrical energy creates enough heat to ignite chemical pellets within the inflator.

Once ignited, these chemicals burn rapidly and produce the pressure necessary to rupture a containment disk in the inert gas canister. The inflator and inert gas canister are sealed and connected so that all of the released gas is directed into the folded SAB cushion, causing the cushion to inflate. As the cushion inflates it will split the inner cover, the intensifier and the outboard side of the seat back trim cover and expand into the area between the outboard side of the front seat and the front door to form a cushion to protect the front seat occupant during a side impact collision or a vehicle rollover incident.

Following the SAB deployment, the cushion slowly deflates by venting the inert gas through the loose weave of the cushion fabric, and through a vent in the cushion. After venting is achieved, the deflated cushion hangs down loosely from the outboard side of the front seat back.

The ORC monitors the condition of the SAB through circuit resistance, and will illuminate the airbag indicator in the instrument cluster and store a Diagnostic Trouble Code (DTC) for any fault that is detected. Proper diagnosis of the SAB inflator and squib circuits requires the use of a diagnostic scan tool and may also require the use of the SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.