Test Notes

Normal Operation
When the air bag diagnostic monitor detects a Diagnostic Trouble Code (DTC) B1913 or 131914 failure, 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.

WARNING: 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).

The air bag diagnostic monitor will make up to three attempts spaced at one minute apart to blow the fuse. 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 been blown or three attempts to blow it have failed, the air bag diagnostic monitor will not attempt to disarm the SRS again until DTC B1924 or B1913 has been repaired and cleared from memory.

The air bag diagnostic monitor also performs several self-tests every time the ignition switch is turned to the RUN position. If any of these tests fail. the air bag diagnostic monitor will flash a Lamp Fault Code (LFC) 24. If any of these conditions later resumes normal operation, the DTC B1924 will be stored in 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 the On-Demand Self Test. An intermittent B1342 cannot exist due to this fact. This DTC indicates that 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

WARNING: 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).

System disarm failure or internal diagnostic failure can be caused by:
- an improper fuse value in the power distribution box mini fuse slot 13.
- 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 C232-13, the 10 A power distribution box Mini Fuse 13 terminal. or elsewhere in the battery feed circuit.
- a vehicle charging system concern preventing the air bag diagnostic monitor from drawing enough current to perform its disarm.
- an internal air bag diagnostic monitor failure of on-board diagnostic or system disarm.
- resistance to ground in the normally open air bag sensor feed Circuits 617 (PK/O), 619 (PK/W), 624 (Y/W), and 625 (Y/LG).