Air Bag Systems

CIRCUIT DESCRIPTION

SIR Schematics: Power, Ground, Serial Data, Indicator and Front Inflatable Restraint Modules:

SIR Schematics: Seat Belt Pretensioners, Side Inflatable Restraint Modules, and Sensors:

The inflatable restraint steering wheel module deployment loop consists of the inflatable restraint steering wheel module, the inflatable restraint steering wheel module coil, and the steering wheel module high and steering wheel module low circuits. A shorting bar is used in the inflatable restraint steering wheel module coil which will short the steering wheel module high and steering wheel module low circuits when the connector is disconnected. This will prevent unwanted deployment of the steering wheel module during servicing. When the ignition is turned ON the Inflatable Restraint Sensing And Diagnostic (SDM) performs continuous diagnostic tests on the deployment loop to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, the SDM will store a Diagnostic Trouble Code (DTC).

CONDITIONS FOR RUNNING THE DTC
Ignition 1 voltage is within the normal operating voltage range.

CONDITIONS FOR SETTING THE DTC
The measured leakage current to ground is above the specified value in the steering wheel module deployment loop.

ACTION TAKEN WHEN THE DTC SETS
The SDM turns the AIR BAG indicator ON.

CONDITIONS FOR CLEARING THE DTC
^ The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
^ A history DTC will clear once 255 malfunction free ignition cycles have occurred.

DIAGNOSTIC AIDS
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:
^ A short to ground in the steering wheel module high or the steering wheel module low circuits
^ The steering wheel module upper coil connector
^ The steering wheel module coil connector
^ The SDM connector
^ An internal SDM malfunction

If an intermittent condition exists, refer to Testing for Intermittent and Poor Connections in Diagrams.

TEST DESCRIPTION

Steps 1-6:

Steps 7-12:

The numbers below refer to step numbers on the diagnostic table.
4. Tests to see if the malfunction is intermittent.
5. Tests to see if the malfunction is caused by the steering wheel module.
7. Tests to see if the malfunction is caused by the steering wheel module coil.
10. Tests to see if there is a short to ground in the steering wheel module high or the steering wheel module low circuits.