The frontal supplemental inflatable restraint (SIR) system consists of the following components:
A frontal collision of sufficient force will deploy the frontal air bags and/or pretensioners. The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device that converts vehicle velocity changes to an electrical signal. The SDM compares these signals to values stored in memory. If the signals exceed a stored value, the SDM will determine the severity of the impact and either cause current to flow through the frontal deployment loops deploying the frontal air bags and pretensioners, or it will deploy the pretensioners only. The SDM, instrument panel module, steering wheel module, steering wheel module coil, seat belt retractor pretensioners, and the connecting wires make up the frontal deployment loops. The SDM continuously monitors the deployment loops for malfunctions and illuminates the AIR BAG indicator if a fault is detected.
Inflatable Restraint Sensing and Diagnostic Module (SDM)
The inflatable restraint sensing and diagnostic module (SDM) is a microprocessor and the control center for the supplemental inflatable restraint (SIR) system. The SDM contains internal sensors along with several external sensors, if equipped, mounted at strategic locations on the vehicle. In the event of a collision, the SDM compares the signals from the internal and external sensors to a value stored in memory. When the generated signals exceed the stored value, the SDM will cause current to flow through the appropriate deployment loops to deploy the air bags. The SDM records the SIR system status when a deployment occurs and illuminates the AIR BAG indicator located in the instrument cluster. The SDM performs continuous diagnostic monitoring of the SIR system electrical components and circuitry when the ignition is turned ON. If the SDM detects a malfunction, a DTC will be stored and the SDM will request the instrument cluster to illuminate the AIR BAG indicator, notifying the driver that a malfunction exists. In the event that ignition positive voltage is lost during a collision, the SDM maintains a 23-volt loop reserve for deployment of the air bags. It is important when disabling the SIR system for servicing or rescue operations to allow the 23-volt loop reserve to dissipate, which could take up to 1 minute.
Removal Procedure
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface
section.
Disable the SIR System. Refer to SIR Disabling
and Enabling.
Disconnect the negative battery cable. Refer to Battery Negative Cable
Disconnection and Connection.
Remove the front side door. Refer t ...
Front Floor Panel Carpet Replacement
Preliminary Procedures
Remove front seats. Refer to Driver or Passenger Seat
Replacement.
Remove rear seat. Refer to Rear Seat Replacement.
Remove the front floor console. Refer to Front Floor Console
Replacement.
Remove front sill panels. Refer to Front Side Door Sil ...
Accident With or Without Air Bag Deployment - Component Inspections
Warning: Proper operation of the Supplemental Inflatable Restraint
(SIR) sensing system requires that any repairs to the vehicle
structure return the vehicle structure to the original production configuration.
Not properly repairing the vehicle structure could cause
non-deployment of the air b ...