Supplemental Inflatable Restraint (SIR)

CIRCUIT DESCRIPTION
During the "Initiator Assembly Resistance Test" the DERM grounds the "Passenger Side Low" terminal "B7" 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 348B and connector terminal contact.

DTC WILL SET WHEN
The combined resistance of the driver inflator module, SIR coil assembly, harness wiring CKT 347A and connector terminal contact is above a specified value. This test is run 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 the driver inflator module circuitry or in the DERM wiring harness circuitry.
2. This test determines whether the malfunction is an open in CKT 347A.
3. This test determines whether the malfunction is in the driver inflator module or the SIR coil assembly.

DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor connection at: the yellow 2-way connector near the base of the steering column, DERM terminals "B8 or "B9", or the connection at the top of steering column to the driver inflator module.