Knee Airbag (Kab)

KABs are used on both the driver and passenger sides of this vehicle. These airbags are passive, inflatable SRS components. The KAB units are concealed below the lower edge of the instrument panel, just beneath the steering column opening cover on the driver side or just beneath the glove box door on the passenger side.

The stamped metal airbag housing is secured by fasteners to the stamped metal lower instrument panel reinforcement of the instrument panel support structure. A molded plastic protective cover is secured over the folded airbag cushion by several hook formations stamped into the airbag housing that are engaged through window openings in tabs integral to the outer perimeter of the cover.

The airbag housing contains the airbag inflator and a heat shield. The airbag inflator is a single-initiator, non-azide hybrid-type unit that is secured to the housing by fasteners and sealed within the airbag housing. The airbag is connected to the vehicle electrical system through a dedicated take out and connector insulator of the instrument panel wire harness that connect directly to the inflator initiator of the airbag.

The KAB is deployed by electrical signals generated by the ORC to which it is connected through a driver 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 cushions protect the lower extremities of the vehicle driver and passenger, and helps to keep the seat occupant properly positioned for the DAB and 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 KAB unit cannot be repaired, and must be replaced if deployed, ineffective or in any way damaged. If the KAB unit is deployed, the steering column opening cover must also be replaced.

The ORC monitors the condition of the knee airbag 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 initiator 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.