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 measures the voltage at "Driver Side Low" and "Passenger Side Low." The DERM then grounds "Passenger Side Low" terminal "B7" and again measures the voltage at "Driver Side Low" and "Passenger Side Low." For a properly operating circuit the voltage measurements during each of these tests will be below a specified value. When the voltages measured at both "Driver Side Low" and "Passenger Side Low" are above a specified value during both tests DTC 25 is set.

DTC WILL SET WHEN
The voltages measured at both "Driver Side Low" and "Passenger Side Low" are above a specified value while the DERM attempts to ground each of these terminals. This test is run during the "Initiator Assembly Resistance Test" and the "10 Minute Loop 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 sets a diagnostic trouble code and sends a command to the instrument cluster to turn "ON" the "AIR BAG" warning lamp.

DTC WILL CLEAR WHEN
The voltage measured at either "Driver Side Low" or "Passenger Side Low" is below a specified value while the DERM grounds either of these terminals.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test determines whether the malfunction is occurring in the steering column circuitry.
2. This test determines whether the malfunction is occurring in the passenger inflator module circuitry.
3. This test checks for a short from the high side of the driver deployment loop to B+.
4. This test checks for a short from the high side of the passenger deployment loop to B+.
5. This test checks for a short from the low side of the driver deployment loop, the low side of the passenger deployment loop and the discriminating sensor interconnect circuit to B+.

DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a short to B+ in the steering column circuits, the passenger inflator module, passenger inflator module jumper, CKT 347, CKT 348, CKT 349, CKT 1403 or CKT 1404. DTC 25 will only set when the short to B+ is present as the ignition switch is turned "ON." When the short to B+ occurs after the "Initiator Assembly Resistance Test" is run DTC 24 is set. If the malfunction is present at the beginning of the next ignition cycle DTC 25 will set and DTC 24 will be moved to a history file. When a scan tool "Clear Codes" command is issued and the malfunction is still present, DTC 25 will not reappear for ten minutes or until the next ignition cycle.