U0137
System
Network (CAN Bus)
Scanner required
Full-system scanner (engine, ABS, SRS, transmission, service resets)

Lost Communication with Trailer Brake Control Module

Understand U0137, common causes, and the right SEAFLO pump to diagnose it.

Integrated trailer brake controller module offline on trucks and SUVs with factory tow packages.

Common symptoms

  • Trailer brakes inop
  • Tow package warning

Typical causes

  • Failed trailer brake module
  • CAN wiring to dash controller
  • Aftermarket trailer wiring shorting bus

What scanner do you need?

Full-system scanner (engine, ABS, SRS, transmission, service resets)

Use live data and freeze frame to confirm the fault before replacing parts. ABS, SRS, and network U-codes usually require a full-system scanner.

Diagnostic tips

  • Record freeze frame data when the code first sets
  • Clear the code only after fixing the root cause
  • Check for related pending codes that point to a common issue
  • Verify battery voltage is above 12.4V before chasing sensor codes

Frequently asked questions

Can I diagnose U0137 with a basic code reader?
U0137 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with U0137?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.