Chart 2

Code 22 (Chart 2):

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. Code 22 will set if:

^ The steering column resistance is less than a specified value.
^ The 430 ohm resistor in the Resistor Module is shorted.
^ The resistance of the 100 ohm resistor in the Resistor Module is too high.
^ The high side of the deployment loop is shorted to the low side of the deployment loop.

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 22 will set if the combined resistance of the Inflator Module, SIR Coil, harness wiring and connector terminal contact in the steering column is less than a specified value ohms.

CONDITIONS TO CLEAR:

Current Code 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 if a short exists in Resistor Module or in wiring from Resistor Module to DERM.

2. Checks if an open circuit exists in the Sense High circuit (Circuit 753).

3. Checks if short causing fault is in the Resistor Module or in the wiring harness.

4. Checks if the 2490 ohm resistor in the Resistor Module is defective.

5. Checks if the 100 ohm resistor in the Resistor Module is defective.