Supplemental Inflatable Restraint (SIR)

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 TABLE TEST DESCRIPTION:
Number(s) below refer to step number(s) on the diagnostic table.
1. The "SIR DIAGNOSTIC SYSTEM CHECK" must be the starting point for all diagnostics.
2. This test checks for proper connector engagement.
3. This test determines if the problem is in the steering column or SIR harness.
4. This test checks for short between CKTs 347A and 348A.
6. This test isolates the malfunction to either the SIR coil assembly or the Inflator Module.

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 TEST" 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.