Supplemental Inflatable Restraint (SIR)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
During the "Initiator Assembly Resistance Test" the DERM grounds the "Driver Side Low" terminal "B8" and turns "ON" the driver current source at the "Driver Side High" terminal "B9." This causes a known amount of current to flow through the driver initiator circuit. By monitoring the difference between the voltage at the "Driver Side High" terminal "B9" and the "Driver Side Low" terminal "B8" the DERM calculates the combined resistance of the driver inflator module, SIR coil assembly, harness wiring CKTs 347A and 348A and connector terminal contact.

DTC WILL SET WHEN
The combined resistance of the driver inflator module, SIR coil assembly, harness wiring CKTs 347A and 348A and connector terminal contact is below a specified value. This test is run once each ignition cycle during the "Initiator Assembly Resistance Test" when: 1) No "higher priority faults" are detected during "Turn-ON," 2) No "higher priority faults" are detected during "Continuous Monitoring" for one second, 3) No "Crank" signal present, 4) "Ignition 1" voltage is above a specified value.

ACTION TAKEN
DERM turns "ON" the "AIR BAG" warning lamp and sets a diagnostic trouble code.

DTC WILL CLEAR WHEN
The ignition switch is turned "OFF."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test determines whether the malfunction is in driver inflator module circuitry or in the DERM wiring harness circuitry.
2. This test checks for a short from the "Driver Side High" circuit to the "Driver Side Low" circuit.
3. This test determines whether the malfunction is in the driver inflator module or in the SIR coil assembly.

DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a short between CKT 347 and CKT 348 or a malfunctioning shorting clip at the base of the steering column. The test for this diagnostic trouble code is only run while the "AIR BAG" warning lamp is performing the bulb check. When a scan tool "Clear Codes" command is issued and the malfunction is still present, the DTC will not reappear until the next ignition cycle.