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B1924 OBD-II Trouble Code: Air Bag Internal Diagnostic Monitor Fault or System Disarm Fault

diagnostic check engine light

B1924 definition

A B1924 trouble code is related to a vehicle’s air bag diagnostic monitor system that can purposely disarm the supplemental restraint system (SRS) if a fault is detected.

What the B1924 code means

B1924 is an OBD-II body code (hence the B) for a voltage or resistance issue within the air bag system circuit. When the ignition is turned to the “on” position, your vehicle’s OBD-II system will perform several self-tests, and a failed test from the air bag system can result in a B1924. This code will attempt to open a specific power distribution box fuse to disarm the SRS, preventing unwanted air bag deployment.

What causes the B1924 code?

The most common causes for a B1924 are:

  • Faulty power distribution box fuse
  • Faulty battery voltage, resistance, or connection
  • Faulty air bag diagnostic monitor
  • Faulty charging system, i.e. faulty alternator

What are the symptoms of the B1924 code?

Symptoms should go unnoticed other than a check engine light and or air bag light on the dash. In the event of an accident, chances are high the air bag will not deploy.

How does a mechanic diagnose the B1924 code?

Because a B1924 may be an intermittent issue caused by improper installation of a battery or previous wiring harness repairs, your mechanic will typically first clear the code and reset the vehicle’s engine computer. After this, they will test the vehicle to ensure it can run a number of self-tests at startup. This will help determine if there is a more serious problem as proper installation of a battery (tightening leads, repairing frayed wires, etc.) can fix a B1924 code.

However, if the code returns after all of this, your mechanic will inspect fuses within the vehicle’s power distribution box. They will replace any blown fuse with an exact value replacement and test for the code through the vehicle’s self-test.

Common mistakes when diagnosing the B1924 code

A blown fuse will not always be the cause of a B1924, so it’s important to try simple fixes first, such as resetting the engine computer or resecuring the battery.

How serious is the B1924 code?

Because a B1924 will attempt, and most likely succeed, in temporarily disarming the SRS, you shouldn’t be in any danger of the air bag deploying. On the flipside, not having a working SRS is a danger in and of itself.

What repairs can fix the B1924 code?

The most common repairs for a B1924 are as follows:

Additional comments for consideration regarding the B1924 code

A B1924 air bag code will be specific to a Ford manufactured vehicle. Any work that needs to be conducted on a vehicle’s SRS should be handled by a trained professional. The air bag could unexpectedly deploy while working to fix a B1924

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