OPERATION

The multistage passenger airbag is deployed by electrical signals generated by the Airbag Control Module (ACM) (also known as the Occupant Restraint Controller/ORC) through the passenger airbag squib 1 and squib 2 circuits to the two initiators in the airbag inflator. By using two initiators, the airbag can be deployed at multiple levels of force. The force level is controlled by the ACM to suit the monitored impact conditions by providing one of three delay intervals between the electrical signals provided to the two initiators. The longer the delay between these signals, the less forcefully the airbag will deploy.

The pyrotechnic-type inflator assembly includes two separate internal chambers filled with solid propellant. When the ACM sends the proper electrical signal to the airbag initiator, the initiator converts the electrical energy into chemical energy. This chemical energy ignites the solid propellant. As the solid propellant burns it produces a large quantity of inert gas. The inflator is sealed to the airbag cushion so that the inert gas is directed into the airbag cushion, causing the cushion to inflate. As the cushion inflates, the passenger airbag door will split at predetermined tear seam lines on the inside surface of the door and the door will pivot out of the way. Following a passenger airbag deployment, the airbag cushion quickly deflates by venting the inert gas through vent holes within the fabric used to construct the sides of the airbag cushion.

Typically, both initiators are used during an airbag deployment event. However, it is possible for only one initiator to be used during a deployment due to an airbag system fault; therefore, it is necessary to always confirm that both initiators have been used in order to avoid the improper disposal of potentially live pyrotechnic materials. (Refer to 8 - ELECTRICAL/RESTRAINTS - STANDARD PROCEDURE - SERVICE AFTER A SUPPLEMENTAL RESTRAINT DEPLOYMENT).

Proper diagnosis of the passenger airbag inflator and squib circuits requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.