DTC 21 and 22

Code 21 And 22 Both Current:

DERM Circuit Detail:

DESCRIPTION:

The DERM injects a current of 75 milliamperes through the steering column from the Force Hi output (terminal A4) to the Force Low input (terminal A10). By monitoring the voltage at the Sense Hi input (terminal A7) and the Sense Low input (terminal A6) the DERM calculates the combined resistance of the Inflator Module, SIR Coil and connector terminal contact in the steering column. Codes 21 and 22 will set if the Force Hi output (terminal A4) is open.

TEST CONDITIONS:

Tested once each ignition cycle during the "Steering Column Resistance Test" if:
1. No faults are detected during "Turn-on".
2. No faults are detected during "Continuous Monitoring" for 1 second.
3. No Crank signal present.

FAILURE CONDITIONS:

Code 21 and 22 will set if the voltage at the Sense Low input (terminal A6) is less than 5 volts during the first portion of the steering column resistance test. This will occur when the Force Hi output (terminal A4) is open and results in an undetermined steering column resistance.

CONDITIONS TO CLEAR:

Current Code 21 and 22 will be cleared each time the Ignition Switch is turned OFF.

ACTION TAKEN:

DERM turns on the "INFLATABLE RESTRAINT" indicator lamp.

NOTES ON FAULT TREE:

1. Checks for open in Force Hi wiring.

2. Checks for open 50 ohm resistor in resistor module.

3. Checks for proper values in resistor module.

4. Checks for short in resistor module wiring harness.

5. Checks for short in resistor module wiring harness.