OBD Guide

U179D

Lost Communication With Brake System Control Module 2 On Chassis Expansion Bus

U179D is an OBD-II diagnostic trouble code meaning: Lost Communication With Brake System Control Module 2 On Chassis Expansion Bus. Common causes: open or short circuit in communication circuit, brake control module 2 malfunction. Estimated repair cost: $56–278.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–278 (est.)

Symptoms

  • Check Engine Light Is On
  • Disabling ABS/ESP systems
  • Other related trouble codes appear
  • Loss of some brake system functions
  • Possible problems with cruise control

Causes

  • Open or short circuit in communication circuit
  • Brake control module 2 malfunction
  • Connector problems or contact corrosion
  • CAN communication bus fault
  • Software error in the module

How to Fix

  1. Check the integrity of the wiring harness to the module
  2. Inspect and clean electrical connectors
  3. Check power supply and grounding of the module
  4. Scan for other related trouble codes
  5. Repair only from an authorized dealer

Related codes

FAQ

What does the U179D code mean?

U179D is an OBD-II diagnostic trouble code that indicates: Lost Communication With Brake System Control Module 2 On Chassis Expansion Bus

What causes a U179D error code?

The most common causes of U179D include: Open or short circuit in communication circuit; Brake control module 2 malfunction; Connector problems or contact corrosion; CAN communication bus fault.

How do I fix a U179D diagnostic trouble code?

To fix U179D: Check the integrity of the wiring harness to the module. Inspect and clean electrical connectors. Check power supply and grounding of the module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U179D?

Do not drive — repair immediately

How much does it cost to fix U179D?

The estimated repair cost for U179D is $56–278. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat