B3891
Trailer Fog Lamps Circuit
B3891 is an OBD-II diagnostic trouble code meaning: Trailer Fog Lamps Circuit. Common causes: open or short circuit in wiring harness, fuse or relay failure. Estimated repair cost: $11–56.
Symptoms
- Trailer fog lights do not work
- Trailer fog lights flashing
- The malfunction indicator on the dashboard lights up
Causes
- Open or short circuit in wiring harness
- Fuse or relay failure
- Problems with the trailer lights themselves
- Control unit malfunction
How to Fix
- Check fuses and relays associated with trailer fog lights
- Inspect the wiring harness for damage
- Check the operation of the trailer fog lights
- If necessary, replace faulty components
- Reset the error and check if it returns
Related codes
Error B3891 by Vehicle Brand
FAQ
What does the B3891 code mean?
B3891 is an OBD-II diagnostic trouble code that indicates: Trailer Fog Lamps Circuit
What causes a B3891 error code?
The most common causes of B3891 include: Open or short circuit in wiring harness; Fuse or relay failure; Problems with the trailer lights themselves; Control unit malfunction.
How do I fix a B3891 diagnostic trouble code?
To fix B3891: Check fuses and relays associated with trailer fog lights. Inspect the wiring harness for damage. Check the operation of the trailer fog lights. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with B3891?
Limited driving only, diagnose soon
How much does it cost to fix B3891?
The estimated repair cost for B3891 is $11–56. Actual cost depends on your vehicle, location, and labor rates.
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