Test Notes

Normal Operation
The air bag diagnostic monitor measures the voltage at C209-14, circuit 937 (R/W), of the air bag diagnostic monitor. Voltage at C209-14, circuit 937 (R/W), should be equal to battery voltage. If the voltage at C209-14, circuit 937 (R/W), drops to less than 8 volts, the air bag diagnostic monitor will flash a lamp fault code (LFC) 12on the air bag indicator. If the voltage at pin C209-14, circuit 937 (R/W), drops to less than 5 volts, the diagnostic trouble code (DTC) B1867 will also be stored in memory. Should the loss of battery voltage at C209-14, circuit 937 (R/W), be intermittent or repaired, the air bag diagnostic monitor will flash a LFC 52 (or higher priority code if one exists) on the next ignition switch cycle.

Possible Causes

WARNING: Do not under any circumstances substitute another fuse value for the 10 A battery fuse 2. Any fuse other than 10 A may cause disarming failure and may result in danger to the occupants of the vehicle. Do not attempt to replace the 10 A fuse 2 unless the air bag system first has been deactivated.

NOTE: If a short to ground exists on any of circuits 607 (LB/O), 614 (GY/O), 615 (GY/W), or 616 (PK/BK), leading to a LFC 13 or 53 and DTC B1913; or, similarly, a short to ground exists on any of circuits 617 (PK/O), 619 (PK/W), 624 (Y/W), or 625 (Y/LG), leading to a LFC 14 or 54 and DTC B1914, the air bag diagnostic monitor will activate an internal solid state switch at C209-13 of the air bag diagnostic monitor. This causes the battery fuse 2 (10 A) to blow, thus disarming the air bag system and preventing inadvertent air bag deployment. If the power distribution box battery fuse 2 has blown, it must be replaced by a 10 A fuse.

Low voltage at air bag diagnostic monitor C209-14, circuit 937 (R/W), can be caused by:
- An open in the battery circuit that would prevent battery positive voltage (B+) from reaching the air bag diagnostic monitor C209-14, circuit 937 (R/W).
- A short to ground on the battery feed circuit between the fuse 2 (10 A) and C209-13, circuit 937 (R/W), or C209-14, circuit 937 (R/W), of the air bag diagnostic monitor.
- A concern in the charging system causing battery voltage to drop below 8 volts.

After the air bag diagnostic monitor has disarmed the air bag system, it will not be enabled to disarm again until the appropriate condition (DTC B1913 or B1914) has been repaired and cleared by performing the appropriate pinpoint tests.