Description And Operation: Operation

The KAB are deployed by electrical signals generated by the Occupant Restraint Controller (ORC) to which it is connected through a driver or passenger KAB line 1 (or squib) circuit to the initiator in the airbag inflator. The hybrid-type inflator assembly for each airbag contains a small canister of highly compressed inert gas. When the ORC sends the proper electrical signal to the airbag inflator, the electrical energy creates enough heat to ignite chemical pellets within the inflator.

Once ignited, these chemical pellets burn rapidly and produce the pressure necessary to rupture a containment disk in the inert gas canister. The inflator is sealed to the airbag cushion and a diffuser in the inflator directs all of the inert gas into the airbag cushion, causing the cushion to inflate. As the cushion inflates, the KAB protective cover will split at predetermined tear seam lines concealed on the underside of the cover, then fold open and out of the way.

The cushion protects the lower extremities of the vehicle driver or front seat passenger and helps to keep the seat occupant properly positioned for the Driver AirBag (DAB) or Passenger AirBag (PAB) deployment during a frontal impact collision. Following an airbag deployment, the KAB cushion quickly deflates by venting the inert gas through the loose weave of the fabric used to construct the instrument panel side of the airbag cushion, and the deflated cushion hangs down loosely from the lower instrument panel.

The ORC monitors the condition of the knee airbags 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 KAB 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.