B3894
Stop Lamp Switch Circuit Plausibility Failure
B3894 is an OBD-II diagnostic trouble code meaning: Stop Lamp Switch Circuit Plausibility Failure. Common causes: faulty brake light switch, open or short circuit in wiring harness. Estimated repair cost: $22–56.
Symptoms
- Brake lights don't work
- Error on the dashboard
- Incorrect operation of cruise control (if equipped)
Causes
- Faulty brake light switch
- Open or short circuit in wiring harness
- Poor contact in connectors
- Problems with the control module
How to Fix
- Check the operation of the brake lights
- Inspect the brake light switch for mechanical damage
- Check the integrity of the wiring harness and contacts
- Replace the switch if necessary
- Reset the error and check if it returns
Related codes
Error B3894 by Vehicle Brand
FAQ
What does the B3894 code mean?
B3894 is an OBD-II diagnostic trouble code that indicates: Stop Lamp Switch Circuit Plausibility Failure
What causes a B3894 error code?
The most common causes of B3894 include: Faulty brake light switch; Open or short circuit in wiring harness; Poor contact in connectors; Problems with the control module.
How do I fix a B3894 diagnostic trouble code?
To fix B3894: Check the operation of the brake lights. Inspect the brake light switch for mechanical damage. Check the integrity of the wiring harness and contacts. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with B3894?
Do not drive — repair immediately
How much does it cost to fix B3894?
The estimated repair cost for B3894 is $22–56. Actual cost depends on your vehicle, location, and labor rates.
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