Diagnostic Aids

An intermittent condition is likely to be caused by a poor connection at terminals A and B of the SIR coil connector at the base of steering column, terminals A and B of the driver inflator module connector at top of the steering column, SDM terminals A1 and A2 or a poor wire to terminal connection in circuit 347 or 348. The test for this DTC is run only while AIR BAG warning light is performing the bulb check, unless DTC 17 or 26 is detected. When a PDT "Clear Codes" command is issued and the malfunction is still present, the DTC will not reappear until the next ignition cycle.

1. Determines whether the malfunction is in the driver inflator module circuitry or in the SDM wiring harness circuitry.
2. Checks whether the malfunction is due to high resistance in circuit 347.
3. Checks whether the malfunction is in the driver inflator module or the SIR coil assembly.
   Fig 1: DTC 21 - Driver Initiator Circuit Resistance High (1 Of 2)

   Courtesy of GENERAL MOTORS CORP.
4. Checks whether the malfunction is due to high resistance in circuit 348.

Fig 2: DTC 21 - Driver Initiator Circuit Resistance High (2 Of 2)

Courtesy of GENERAL MOTORS CORP.