Fault Code 53 Front impact sensor Resistance to Ground

FAULT CODE 53
Front Impact Sensors Circuits Resistance to Ground or Internal Diagnostic Monitor Failure


Normal Operation
The Air Bag Diagnostic Module (DM) measures the voltage on pins 2,6,17 and 18. If there is any resistance to ground on any of these pins or across the front impact sensors contacts, it will cause the diagnostic voltage on these pins to drop below normal levels. If the DM measures voltage drop to between Sand 10 volts, the DM senses an internal voltage regulation failure and code 53 will be present.

A direct short to ground in the front impact sensor circuits will drop the voltage to less than 5 volts and code 14 will be present.


NOTE: The DM also performs several system self-tests every ignition cycle. If any of these tests fail, fault code 53 will be present.


Fault Diagnosis
1. System verification
- Disarm the Airbag/SRS system.
- Disconnect the battery ground lead, allow one minute for DM back-up power to drain.
- Disconnect the DM.
- Remove the plastic locking wedge from the grey harness multi-plug connector.
- Measure the resistance between pin 3 (ground) and the following circuits:
- Pin 2 (ON)
- Pin 6 (YU)
- Pin 17 (KU)
- Pin 18 (KG)
- Are all circuit readings infinite (open circuit)?

Yes - Renew DM.
No - Proceed to step 2.

2. Impact sensor open circuit - check
- Using schematic, identify suspect sensor and circuitry.
- Disconnect the suspect sensor.
- Measure the resistance across the normally open contacts.
- Is the resistance reading infinite (open circuit)?

Yes - Locate and repair short to ground on low resistance circuit.
No - Renew front impact sensor.

Electrical Schematic-Front Impact Sensor Circuits Resistance To Ground Or Internal DM Failure, Fig.1:

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