OBD Guide

C1112

Trailer Brake Signal to Trailer Brake Power Control Module Circuit Malfunction

C1112 is an OBD-II diagnostic trouble code meaning: Trailer Brake Signal to Trailer Brake Power Control Module Circuit Malfunction. Common causes: broken or damaged wires in the trailer brake signal circuit, poor contact in connectors. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Trailer brakes do not work
  • The brake system fault light comes on
  • Error C1112 persists after scanning

Causes

  • Broken or damaged wires in the trailer brake signal circuit
  • Poor contact in connectors
  • Trailer brake power control module malfunction
  • Short circuit in the circuit

How to Fix

  1. Check the integrity of the wiring harness connecting the vehicle to the trailer.
  2. Inspect and clean the contacts in the connectors
  3. Check the operation of the trailer brake power control module
  4. If necessary, replace damaged wires or module

Related codes

FAQ

What does the C1112 code mean?

C1112 is an OBD-II diagnostic trouble code that indicates: Trailer Brake Signal to Trailer Brake Power Control Module Circuit Malfunction

What causes a C1112 error code?

The most common causes of C1112 include: Broken or damaged wires in the trailer brake signal circuit; Poor contact in connectors; Trailer brake power control module malfunction; Short circuit in the circuit.

How do I fix a C1112 diagnostic trouble code?

To fix C1112: Check the integrity of the wiring harness connecting the vehicle to the trailer.. Inspect and clean the contacts in the connectors. Check the operation of the trailer brake power control module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C1112?

Limited driving only, diagnose soon

How much does it cost to fix C1112?

The estimated repair cost for C1112 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat