Test Notes

Normal Operation
The air bag diagnostic monitor measures the voltage at C233-23, circuit 625 (Y/LG), and C233-24, circuit 624 (Y/W), of the air bag diagnostic monitor connector. The voltage at these pins varies with charging system voltage (the expected voltages are shown in the following table). If the air bag diagnostic monitor measures a voltage of less than five volts on either of these pins, the air bag diagnostic monitor will store in memory the Diagnostic Trouble Code (DTC) B1914 and flash Lamp Fault Code (LFC) 14 on the air bag indicator to indicate a possible short to ground on these circuits.

At the same time the air bag diagnostic monitor begins flashing LFC 14, it attempts to disarm the air bag system to prevent inadvertent deployment of the air bag(s) by blowing the battery fuse 4 (10 A) feeding air bag diagnostic monitor in C232-13, circuit 937 (R/W), and C232-14, circuit 937 (R/W). It attempts to blow the fuse by activating an internal solid state switch which shorts the battery feed at C232-13, circuit 937 (R/W), to sheet metal ground at the air bag diagnostic monitor bracket.

The air bag diagnostic monitor will make up to three attempts to blow this fuse, spaced one minute apart.
- If the air bag diagnostic monitor has blown the 10 A battery fuse and thus removed battery voltage at C232-14, circuit 937 (R/W), a DTC B1867 will be stored. Refer to Pinpoint Test A, Normal Operation for further information.
- If the air bag diagnostic monitor attempts to blow the 10 A battery fuse three times and fails each time, a DTC B1924 will be stored. Refer to Pinpoint Test Q, Normal Operation for further information.
- After the 10 A fuse is blown or three attempts to blow it fail, the air bag diagnostic monitor will not attempt to disarm again until DTC B1914 has been repaired and cleared by performing Pinpoint Test C.
- Should the short on C233-23 and C233-24 be intermittent or repaired, the air bag diagnostic monitor will flash LFC 54 (or a higher priority LFC such as LFC 12 if one exists) on the next ignition switch cycle.

Possible Causes

WARNING: Repair of Lamp Fault Code (LFC) 13 (DTC B1913) will usually occur after the repair of LFC 12 (DTC B1867) has been completed. Do not under any circumstances substitute another fuse value for the 10 A battery fuse 4. 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 battery fuse 4 unless the air bag system first has been deactivated.






Low voltage at the air bag diagnostic monitor C233-23, C232-15, C232-16 or C233-24 can be caused by:
- A short to ground on circuits 617 (PK/O), 619 (PK/W), 624 (Y/W), or 625 (Y/LG) causing the diagnostic voltage to drop.
- An internal short to case ground within either of the air bag sensors.