Test Notes

Normal Operation
The air bag diagnostic monitor measures the voltage at pin C2Ob-8, circuit 8-MA22 (WH/VT) and pin C2Ob- 11, circuit 8MA22 (WH/VT) and C2Ob- 11, circuit 8-MA18 (WH/BU) varies with the charging system voltage as shown in the table:




Air Bag Diagnostic Monitor Typical Pin Voltages With System Connected and Engine Running

Note that circuits 8-MA18 (WH/BU) and 8-MA22 (WM/VT) are connected to circuit 31S-MA8 (BK/OG) and circuit 31S-MA11 (BK/WH) through the driver side air bag module and passenger side air bag module. Also, note that circuit 31S-MA8 (BK/OG) and 31S-MA11 (BK/WH) are connected to the RH and LH crash sensor feed circuits through diodes inside the air bag diagnostic monitor. If the air bag diagnostic monitor measures a voltage of 2.0 volts or less at pin C2Ob-8, circuit 8-MA22 (WH/VT) or pin C20b. 11, circuit 8-MA18 (WH/BU), the air bag diagnostic monitor will flash Diagnostic Trouble Code (DTC) 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 DTC 13, the air bag diagnostic monitor blows its internal thermal fuse. This disables the air bag deployment circuit. If the voltage at pin C20b-8, circuit 8-MA22 (WH/VT) or pin C2Ob- 11, circuit 8-MA18 (WH/BU) returns to normal (because the short to ground no longer exists), DTC 51 will be flashed on the air bag indicator, due to the open thermal fuse. O: LFC/DTC 51 - Diag Mon Int Thermal Fuse Due to Intermit Short

Possible Causes
Low voltage at air bag diagnostic monitor pins C20b-8, circuit 8MA22 (WH/VT) and C2Ob-11, circuit 8-MA18 (WH/BU) can be caused by:
1. A short to ground within the wiring harness on circuits 9-MA21 (BN/WH), 29S-MA1 (OG/BU), 8-MA18 (WH/BU), 8-MA22 (WH/VT), 29S-MA8 (00), 29S-MA11 (OG/WH), 31S-MA8 (BK/OG), or3IS-MA11 (BK/WH).
2. An internal short to ground within the air bag sliding contact causing the driver side air bag module circuit(s) to be shorted to ground.
3. An internal short to ground within the safing sensor causing circuit 9-MA21 (BN/WH), 29S-MA1 (OG/BU), 8-MA18 (WH/BU), 8-MA22 (WH/VT), 29S-MA8 (OG), or 29S-MA11 (OG/WH) to be shorted to ground.
4. An internal short to ground within one or more of the crash sensors causing circuits 31S-MA26 (BK/RD) and 31S-MA25 (BK/ON) to be shorted to ground.


NOTE: Circuits 31S-MA26 (BK/RD) and 31S-MA25 (BK/ON) 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.

5. An internal short to case ground within the driver side air bag module or passenger side air bag module.