OBD Codes

C0055

ABS Motor Relay Circuit Malfunction

Severeelectrical

Overview

The C0055 code indicates that the chassis control module has detected a abs motor relay circuit malfunction condition. This diagnostic trouble code relates to the electrical control circuits within the vehicle's chassis safety systems, including ABS, traction control, and stability control. When this code is stored, one or more chassis safety features may be disabled, which can reduce braking performance and vehicle stability under adverse driving conditions.

Symptoms

  • Power steering assist reduced or lost
  • Electronic parking brake malfunction warning
  • Reduced braking performance in emergency stops
  • Suspension ride quality noticeably degraded

Common Causes

  • Faulty ABS control module (EBCM)
  • Faulty ABS valve body or solenoid pack
  • Corroded or damaged wiring in the ABS harness
  • Failed ABS hydraulic pump motor

Diagnosis Steps

  1. 1Connect an OBD-II scanner and read all stored chassis trouble codes and freeze frame data
  2. 2Inspect the ABS/ESC module connectors for corrosion, damage, or loose pins
  3. 3Check the ABS fuse and relay in the fuse box; replace if blown or faulty
  4. 4Test the ABS pump motor operation using a scan tool bi-directional command
  5. 5Measure circuit voltage and ground at the ABS module with a multimeter

Estimated Repair Cost

$150$1,200

Cost varies by vehicle, location, and repair shop. Includes parts and labor.

Commonly Affected Vehicles

Honda AccordMercedes-Benz C-ClassToyota TundraFord Explorer

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Frequently Asked Questions

Your standard brakes will still work, but the anti-lock braking function is disabled. This means wheels can lock up during hard braking, especially on wet or icy roads. Avoid aggressive driving and have the system inspected promptly.