Test Notes

Fault Code 13 - Air Bag Module or Crash Sensor Circuit Short to Ground

Normal Operation






The air bag diagnostic monitor measures the voltage at pin 11 (circuit 614 GY/O) of the air bag diagnostic monitor connector. The voltage at pin 11 varies with charging system voltage (the expected voltage at pin 11 is shown in the chart).

Note that circuit 614 is connected to circuit 615 (GY/W) through the driver side air bag module. Also, note that circuit 615 is connected to the center air bag sensor feed circuits (617 [PK/O] and 619 [PK/W]) through a diode inside the air bag diagnostic monitor. If the air bag diagnostic monitor measures a voltage of 2.0 volts or less at pin 11, the air bag diagnostic monitor will flash out code 13 to indicate a possible short to ground on this circuit (see possible causes for additional circuits that may be shorted to ground). When flashing code 13, the air bag diagnostic monitor blows its internal thermal fuse. This disables the air bag deployment circuit. If the short to ground is corrected, the voltage at pin 11 will return to normal and a diagnostic trouble code 51 will flash, indicating an open thermal fuse (see Diagnostic Trouble Code 51 for details).

NOTE: Diagnostic trouble code 13 will flash only while the short to ground is present.

Possible Causes

NOTE: Circuits 617 (PK/O) and 619 (PK/W) are connected together inside the air bag diagnostic monitor. Therefore, a short to ground on any of these circuits will short all of the circuits to ground.

Low voltage at pin 11 of the air bag diagnostic monitor can be caused by:

1. A short to ground within the main wiring on circuits 614 (GY/O), 615 (GY/W), 623 (P/W), 617 (PK/O) or 619 (PK/W) causing the diagnostic voltage to drop.
2. An internal short to ground within the air bag sliding contact causing the driver side air bag circuit(s) to be shorted to ground.
3. An internal short to ground within the LH cowl side air bag sensor and bracket causing circuit 614 (GY/O) or 623 (P/W) to be shorted to ground.
4. An internal short to ground within one or both center air bag sensor and bracket and RH cowl side air bag sensor and bracket causing circuits 617 (PK/O) and 619 (PK/W) to be shorted to ground.
5. An internal short to case ground within the driver side air bag module.