DTC 13: Air Bag Or Crash Sensor Circuit Shorted to Ground

Electrical Schematic:

Pin 11 Voltage Chart:

Normal Operation
The diagnostic monitor measures the voltage at pin 11 (circuit 944A "GN/W") of the diagnostic monitor connector. The voltage at pin 11 varies with the charging system voltage as shown in the provided chart.

Note that circuit 944A is connected to circuit 937 ("GY") through the driver side air bag and safing sensor. Also, note that circuit 937 is connected to the RH, LH and center radiator crash sensor feed circuits (933 ["BR/GN"], 932 ["BR/N"], and 931 ["BF/BK"]) through a diode inside the diagnostic monitor. If the diagnostic monitor measures a voltage of 2.0 volts or less at pin lithe monitor will flash a code 13 to indicate a possible short to ground on this circuit (see Possible Causes below for additional circuits that may be shorted to ground). When flashing code 13, the diagnostic monitor blows its internal thermal fuse. This disables the air bag deployment circuit. If the voltage at pin 11 returns to normal (because the short to ground no longer exists), a fault code 51 will be present on the air bag lamp, due to the open thermal fuse (see DTC 51 for details).

Possible Causes
Low voltage at diagnostic monitor pin 11 can be caused by:
1. A short to ground within the wiring harness on circuits 944A ("GN/W"), 944 ("GN/W"), 944B ("GN/W"), 938 ("R"), 937 ("GY"), 933 ("BR/GN"), 932 ("BR/R") or 931 ("BR/BK") causing the diagnostic monitor voltage to drop.
2. An internal short to ground within the clockspring assembly causing the driver side air bag circuit(s) to be shorted to ground.
3. An internal short to ground within the safing sensor causing circuit 944A ("GN/W"), 944 ("GN/W"), 944B ("GN/W"), or 938 ("R") to be shorted to ground.

NOTE: Circuits 933 ("BR/GN"), 932 ("BR/R") and 931 ("BR/BK") are all connected together inside the diagnostic monitor. Therefore, a short to ground on any of these circuits will short all of the circuits to ground.

4. An internal short to ground within one or more of the crash sensors causing circuits 933 ("BR/GN"), 932 ("BR/R"), and 931 ("BR/BK") to be shorted to ground.
5. An internal short to case ground within the driver side air bag.

Pinpoint Test Steps:

13-1 - 13-4:

13-5 - 13-6: