Test Notes

WARNING: UNDER NO CIRCUMSTANCES SHOULD ANOTHER FUSE VALUE BE SUBSTITUTED FOR THE 10A 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 FUSE UNLESS THE AIR BAG SYSTEM FIRST HAS BEEN DEACTIVATED.

NORMAL OPERATION
When the air bag diagnostic monitor detects a DTC B1913 or B1914 failure, it attempts to disarm the air bag system to prevent inadvertent deployment of the air bag(s) by blowing Fuse 16 (10A) feeding air bag diagnostic monitor Pins C1-13 and C1-14. It attempts to blow Fuse 16 (10A) by activating an internal solid state switch which shorts the battery feed at Pin C1-13 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 at one minute apart. If the air bag diagnostic monitor has blown the fuse and thus removed battery voltage at Pin C1-14, a DTC B1867 will be stored. If the air bag diagnostic monitor attempts to blow Fuse 16 (10A) three times and fails each time, a DTC B1924 will be stored. After Fuse 16 (10A) is blown or three attempts to blow it fail, the air bag diagnostic monitor will not attempt to disarm again until DTC B1924 or B1913 has been serviced and cleared.

The diagnostic monitor also performs several self-tests every time the ignition switch is turned to RUN position. If any of these tests fail, the air bag diagnostic monitor will flash lamp fault code 24. If any of these conditions later resumes normal operation, the DTC B1924 will be stored in background memory.

The failure will either generate a DTC B1924 or B1342, depending on the cause of the failure. DTC B1342 is a special case DTC that will only be retrieved as a result of running on-demand self test from a tester. An intermittent B1342 cannot exist due to this fact. This DTC indicates than an internal microprocessor fault exists in the air bag diagnostic monitor. DTC B1924 covers the other internal air bag diagnostic monitor faults and is handled like any other DTC.

POSSIBLE CAUSES

System Disarm Failure Or Internal Diagnostic Failure Can Be Caused By:

1. An improper fuse value in the battery circuit feeding air bag diagnostic monitor Pins C1-13 and C1-14.

2. Excessive resistance or opens in the battery feed circuit due to corrosion, poor crimps, etc. The excess resistance could occur in the wiring at the air bag diagnostic monitor harness Pin C1-13, the 10A battery fuse terminal, or elsewhere in the battery feed circuit.

3. A vehicle charging system concern could prevent the air bag diagnostic monitor from drawing enough current to perform its disarm.

4. An internal air bag diagnostic monitor failure on on-board diagnostic or system disarm.

5. Resistance to ground in the normally open primary crash sensor feed Circuits 621 (W/Y), 619 (PK/W), 624 (Y/W) and 625 (Y/LG).