Fault Code 22 Impact Sensor Output Circuit Shorted to Battery

FAULT CODE 22
Safing Impact Sensor Output Circuit Shorted to Battery Voltage

Normal Operation
The Air Bag Diagnostic Module (DM) measures voltage level at pins 11 and 12 which varies in accordance with charging voltage. If voltage measured at these two pins exceeds 5 V the MIL Lamp will illuminate and fault code 22 will be present, indicating a short
to battery voltage.

Possible Causes
- Airbag supply wiring faulty.
- Safing impact sensor supply wiring faulty.
- Safing impact sensor internal contacts short circuit.
- Cable reel cassette faulty.
- Charging system voltage too high (above 17 V)

Fault Diagnosis
1. Voltage-check
- Disarm the Airbag/SRS system.
- Measure the voltage between DM pin 11 and pin 3 (ground) and compare to following table.

Voltage Comparison Table:

- Is voltage 0.5 V or more above correct readings?

No - Renew DM.
Yes - Examine wiring continuity from pin 11 DM to safing sensor pin 3. repair faults as necessary.

Proceed to step 2.

2. Resistance - check
- Measure resistance across safing sensor contacts.
- Does resistance value indicate open circuit

Yes - Examine harness wiring for short circuits. repair faults as necessary.
No - Renew safing sensor.

3. On completion
- Arm and verify the Airbag/SRS system.

Electrical Schematic-Safing Impact Sensor Output Circuit Shorted To Battery Voltage, Fig.1:

1. Instrument Panel Fuse
2. Engine Compartment Fuse
3. Safing Sensor
4. Cable Reel Cassettes
5. Driver-side Airbag
6. Pressure-side Airbag
7. RH Impact Sensor
8. LH Impact Sensor
9. Airbag MIL Lamp
10. Diagnostic Module