Action Taken

DERM turns on INFLATABLE RESTRAINT indicator light.

NOTE: Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

Checks whether fault is in steering column or diagnostic circuitry.
Checks integrity of 430-ohm resistor and associated circuitry in resistor module.
Checks whether steering column fault is due to SIR coil assembly or inflator module.
Checks integrity of 100-ohm resistor and associated circuitry in resistor module.
Checks integrity of SENSE LOW 2490-ohm resistor and associated circuitry in resistor module.
Checks for a short from FORCE HIGH circuit No. 714 to SENSE HIGH circuit No. 753.
Checks whether fault is due to a short to voltage in SENSE HIGH circuit in SENSE HIGH circuit No. 753 or a faulty DERM.

Fig 1: CODE 21 (1 of 2), Steering Column Resistance too High

Courtesy of GENERAL MOTORS CORP.

Fig 2: CODE 21 (2 of 2), Steering Column Resistance too High

Courtesy of GENERAL MOTORS CORP.