Test Notes

WARNING: SERVICING LAMP FAULT CODE 14 (DTC B1914) WILL USUALLY OCCUR AFTER SERVICING OF LAMP FAULT CODE 12 (DTC B1867) HAS BEEN COMPLETED. UNDER NO CIRCUMSTANCES SUBSTITUTE ANOTHER FUSE VALUE FOR THE 10A BATTERY FUSE. 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 BATTERY FUSE UNLESS THE AIR BAG SYSTEM FIRST HAS BEEN DEACTIVATED (REFER TO DEACTIVATION PROCEDURE FOR DETAILS).






NORMAL OPERATION
The air bag diagnostic monitor measures the voltage at Pins C2-23, Circuit 625 (Y/LG) and C2-24, 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 DTC B1914 and flash lamp fault code 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 lamp fault code 14, it attempts to disarm the air bag system to prevent inadvertent deployment of the air bag(s) by blowing the battery fuse 4(10A) feeding air bag diagnostic monitor Pins C1-13, Circuit 937 (R/W) and C1-14, Circuit 937 (R/W). It attempts to blow the fuse by activating an internal solid state switch which shorts the battery feed at Pin C1-13, Circuit 937 (R/W) to sheet metal ground at the air bag diagnostic monitor's bracket.

The air bag diagnostic monitor will make up to three attempts to blow this fuse, spaced at one minute apart. If the air bag diagnostic monitor has blown the fuse and thus removed battery voltage at Pin C1-14, Circuit 937 (R/W), a DTC B1867 will be stored. If the air bag diagnostic monitor attempts to blow the 10A battery fuse three times and fails each time, a DTC B1924 will be stored.

After the 10A fuse is blown or three attempts to blow it fail, the air bag diagnostic monitor will not attempt to disarm again until the DTC B1914 has been serviced and cleared by performing DTC.

Should the short on Pins C2-23 and C2-24 be intermittent or repaired, the air bag diagnostic monitor will flash lamp fault code 54 (or a higher priority DTC such as lamp fault code 12 if one exists) on the next ignition switch cycle.

POSSIBLE CAUSES

Low Voltage at Diagnostic Monitor Pins C2-23, C1-15, C1-16 or C2-24 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 primary crash sensors.