Air Bag Systems

Schematic:

CIRCUIT DESCRIPTION
When you first turn ON the ignition, the inflatable restraint sensing and diagnostic and seat belt pretensioner module (SDM) performs tests to diagnose critical malfunctions within itself. Then, the SDM proceeds with the RESISTANCE MEASUREMENT test to measure the deployment loop resistances to ensure they are within their respective normal resistance ranges. Upon passing these tests, the energy reserve is charged and the firing transistors are tested. The SDM then goes into CONTINUOUS MONITORING mode.

CONDITIONS FOR RUNNING THE DTC
When the ignition voltage is within the normal operating voltage range, the SDM monitors all deployment loops in order to detect a leakage current to ground in the driver frontal air bag deployment loop.

CONDITIONS FOR SETTING THE DTC
The measured leakage current to ground is above the specified value in the driver frontal air bag deployment loop.

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

CONDITIONS FOR CLEARING THE DTC
^ You can issue a CLEAR CODES command.
^ A history DTC will clear once 255 malfunction free ignition cycles have occurred.

DIAGNOSTIC AIDS
A short to ground in the driver frontal air bag deployment loop can cause an intermittent condition. Inspect the driver frontal high and driver frontal low circuits carefully for cutting or chafing.

TEST DESCRIPTION

Steps 1 - 7:

Steps 8 - 13:

The numbers below refer to step numbers on the diagnostic table.
2. This step checks the inflatable restraint steering wheel module coil integral connector.
4. This step checks to see if the inflatable restraint steering wheel module is defective.
6. This step checks to see if the inflatable restraint steering wheel module coil is defective.
8. This step checks to see if there is a short to ground in the driver frontal high circuit.
10. This step determines if there is a short to ground in the driver frontal low circuit or if there is a malfunctioning SDM.
13. This step clears all DTCs.