Test Notes

Normal Operation
The air bag diagnostic monitor measures the voltage of the air bag sensors at Pins C233-23, Circuit 625 (Y/LG) and C233-24, Circuit 624 (Y/W). The voltage at these pins varies with the charging system voltage. if the air bag diagnostic monitor measures a voltage of less than five volts on either of these pins, it will store a Diagnostic Trouble Code (DTC) B1914 in memory and flash a 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 Supplemental Restraint System (SRS) by activating an internal solid state switch at Pin C232-13, Circuit 937 (R/W). The activation of this switch shorts Circuit 937 (R/W) to ground, causing the power distribution box Mini Fuse 13 (10 A) to open, disarming the SRS and preventing inadvertent air bag deployment.

The air bag diagnostic monitor will make three attempts spaced one minute apart to blow the power distribution box Mini Fuse 13 (10 A).

If the attempt to blow the fuse is successful, a DTC B1867 will be stored in memory.

If the attempts to blow the fuse are unsuccessful, a DTC B1924 will be stored in memory.

After the power distribution box Mini Fuse 13 (10 A) has blown or three attempts to blow it have failed, the air bag diagnostic monitor will not attempt to disarm the SRS again until DTC B1914 has been repaired and cleared from memory.

Should the low voltage or short to ground on these pins 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) 14/DIAGNOSTIC TROUBLE CODE (DTC) B1914 WILL USUALLY OCCUR AFTER REPAIR OF LFC 12/DTC B1867 HAS BEEN COMPLETED. DO NOT UNDER ANY CIRCUMSTANCES SUBSTITUTE ANOTHER FUSE VALUE FOR THE POWER DISTRIBUTION BOX MINI FUSE 13 (10 A). ANY FUSE OTHER THAN 10 A CAN CAUSE DISARMING FAILURE AND CAN RESULT IN DANGER TO THE OCCUPANTS OF THE VEHICLE. DO NOT ATTEMPT TO REPLACE THE POWER DISTRIBUTION BOX MINI FUSE 13 (10 A) UNLESS THE BATTERY GROUND CABLE HAS BEEN DISCONNECTED AND THE BACKUP POWER SUPPLY ENERGY HAS BEEN DEPLETED. TO DEPLETE THE BACKUP POWER SUPPLY ENERGY, DISCONNECT THE BATTERY GROUND CABLE AND WAIT ONE MINUTE. BE SURE TO DISCONNECT AUXILIARY BATTERIES AND POWER SUPPLIES (IF SO EQUIPPED).

Low voltage at the air bag diagnostic monitor Pins C233-23. C232-15, C232-16 or C233-24 can be caused by.
- a short to ground on Circuit; 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.