OBD Codes

C0187

EBD Hydraulic Control Unit Malfunction

Severeelectrical

Overview

The C0187 code indicates that the chassis control module has detected a ebd hydraulic control unit 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

  • Unusual brake pedal feel or pulsation
  • Loss of traction control function
  • Loss of stability control function
  • Power steering assist reduced or lost

Common Causes

  • Short circuit in solenoid valve wiring
  • Faulty ABS valve body or solenoid pack
  • Water intrusion into electrical connectors
  • Damaged suspension control module

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

Chevrolet SilveradoToyota TundraBMW 3 SeriesDodge Ram 1500

Related Codes

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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.