Normal Operation

The air bag diagnostic monitor (14B056) measures the voltage at pin C209-14, circuit 937 (R/W), of the air bag diagnostic monitor connector. Voltage at pin C209-14, circuit 937 (R/W) should be equal to battery voltage. If the voltage at pin C209-14, circuit 937 (R/W), drops to less than 8 volts, the air bag diagnostic monitor will flash a lamp fault code (LFC) 12 on 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 pin 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 10A BATTERY FUSE 2. ANY FUSE OTHER THAN 10A MAY CAUSE DISARMING FAILURE AND MAY RESULT IN DANGER TO THE OCCUPANTS OF THE VEHICLE. DO NOT ATTEMPT TO REPLACE THE 10A FUSE 2 UNLESS THE AIR BAG SYSTEM FIRST HAS BEEN DEACTIVATED. (REFER TO THE DEACTIVATION PROCEDURE IN THIS SECTION).

NOTE: If a short to ground exists on any of circuits 607 (LB/O), 614 (GY/O), 615 (GY/W), or 616 (PK/BK), 1112 (W/LB), 1113 (Y/LG), 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 pin C209-13 of the air bag diagnostic monitor. This causes the battery fuse 2 (10A) 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 10A fuse.

Low voltage at air bag diagnostic monitor pin 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 pin C209-14, circuit 937 (R/W).
A short to ground on the battery feed circuit between the fuse 2 (10A) and pin C209-13, circuit 937 (R/W), or pin 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 until the appropriate condition (DTC B1913 or B1914) has been repaired and cleared by performing the appropriate pinpoint tests.