Lost Communication With Trailer Brake Control Module
The U0197 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Trailer Brake Control Module. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $600 (parts and labor)
Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.
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Common Symptoms
- Trailer brake controller not functioning
- Trailer brake warning light on
- No braking force applied to trailer
- Trailer sway control inoperative
- Integrated trailer brake display shows error
Probable Causes (Ranked by Likelihood)
- Failed integrated trailer brake control module Very High
- Damaged trailer wiring harness or connector High
- Corroded trailer plug connector Moderate
- Aftermarket brake controller interfering with factory system Low
Step-by-Step Diagnostic Procedure
-
Inspect the trailer connector plug for corrosion or damage
-
Check the trailer brake controller fuse
-
Verify the trailer wiring harness at the hitch receiver
-
Test the system with a trailer brake simulator
-
Check for aftermarket controllers conflicting with factory system
Frequently Asked Questions
Can I drive with code U0197?
Yes, but do not tow a trailer until the trailer brake system is repaired. Towing without trailer brakes is dangerous and may be illegal.
What causes U0197?
Most commonly a corroded trailer plug connector or failed integrated trailer brake controller. Regular trailer plug maintenance can prevent this issue.
Is U0197 expensive to fix?
Typically $100 to $600. Cleaning or replacing the trailer connector is inexpensive. Module replacement is more costly but less common.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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