Supplemental Inflatable Restraint (SIR)

CIRCUIT DESCRIPTION
The deployment loops consist of the driver inflator module, passenger inflator module, SRS coil assembly, center sensor assembly and associated wires. The center sensor assembly injects a small amount of current trough the deployment loops through the D+ CKT output, terminal "B3" and the P+ CKT output, terminal "B2." By monitoring the voltage at the D- CKT input, terminal "B4" and the P- CKT input terminal "B1," the center sensor assembly calculates the combined resistance of the inflator modules, SRS coil assembly and their associated wiring.

FAILURE CONDITIONS
DTC 12 will set if the center sensor assembly detects a short to B+ in the deployment loops.

ACTION TAKEN
The center sensor assembly will illuminate the "AIR BAG" indicator and open the safety circuit, disabling the SRS.

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test determines whether the fault is in the passenger inflator module.
2. This test determines whether the fault is in the steering column components or in the SRS circuitry.
3. This test checks for a short to B+ in the D+ CKT.
4. This test determines whether the steering column fault is due to a faulty SRS coil assembly or a faulty driver inflator module.
5. This test checks for a short to B+ in the D- CKT.
6. This lest checks for a short to B+ in the P+ CKT.
7. This test determines if the fault is due to a short to B+ in the P- CKT or a faulty center sensor assembly.