C1749
Trailer Input Circuit Failure
C1749 is an OBD-II diagnostic trouble code meaning: Trailer Input Circuit Failure. Common causes: open or short circuit in trailer wiring harness, corrosion of contacts in connectors. Estimated repair cost: $33–167.
Symptoms
- False alarm of trailer indicator
- Incorrect operation of the stabilization system
- No response to trailer connection
Causes
- Open or short circuit in trailer wiring harness
- Corrosion of contacts in connectors
- Trailer control module malfunction
- Circuit Grounding Problems
How to Fix
- Check the integrity of the trailer wiring harness
- Inspect and clean connector contacts
- Check voltage and resistance in the circuit
- Test or replace trailer control module
Related codes
FAQ
What does the C1749 code mean?
C1749 is an OBD-II diagnostic trouble code that indicates: Trailer Input Circuit Failure
What causes a C1749 error code?
The most common causes of C1749 include: Open or short circuit in trailer wiring harness; Corrosion of contacts in connectors; Trailer control module malfunction; Circuit Grounding Problems.
How do I fix a C1749 diagnostic trouble code?
To fix C1749: Check the integrity of the trailer wiring harness. Inspect and clean connector contacts. Check voltage and resistance in the circuit. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with C1749?
Do not drive — repair immediately
How much does it cost to fix C1749?
The estimated repair cost for C1749 is $33–167. Actual cost depends on your vehicle, location, and labor rates.
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