C0004 Code – Traction Control Valve 4 Control Circuit

The C0004 Diagnostic Trouble Code (DTC) indicates that the Anti-lock Braking System (ABS) or Electronic Stability Control (ESC) module has detected an electrical malfunction in the Traction Control Valve 4 Control Circuit. This valve is part of the ABS Hydraulic Control Unit (HCU), which manages brake pressure during ABS and traction control operation.

What Does C0004 Mean?

C0004 means the ABS control module has identified a fault in the electrical circuit controlling Traction Control Valve 4. The problem may involve an open circuit, short to ground, short to battery voltage, poor electrical connection, or an internal failure of the hydraulic control unit.

Symptoms of C0004

• ABS warning light illuminated.
• Traction Control (TCS) warning light on.
• Electronic Stability Control (ESC) warning light illuminated.
• ABS function disabled.
• Reduced traction control performance.
• Reduced vehicle stability during slippery road conditions.

Common Causes

• Faulty ABS hydraulic control unit (HCU).
• Defective traction control solenoid valve.
• Damaged or shorted wiring harness.
• Loose, corroded, or damaged electrical connectors.
• Poor ground connection.
• Faulty ABS control module (rare).

How to Diagnose C0004

1. Scan the ABS module for all stored fault codes.
2. Inspect the wiring harness and connectors for damage or corrosion.
3. Measure the resistance of the valve control circuit.
4. Verify power and ground at the ABS hydraulic control unit.
5. Use a professional scan tool to command the traction control valve on and off.
6. Inspect the hydraulic control unit if electrical tests are normal.

How to Fix C0004

• Repair damaged wiring or poor electrical connections.
• Replace the faulty traction control solenoid if it is serviceable.
• Replace the ABS hydraulic control unit if defective.
• Repair poor ground connections.
• Replace or reprogram the ABS control module if necessary.

Can You Drive With C0004?

The vehicle is generally still drivable, but it is not recommended. Although normal braking usually remains operational, the ABS, traction control, and electronic stability systems may be disabled, reducing vehicle safety during emergency braking or low-traction driving conditions.

Repair Cost Estimate

Repair	Estimated Cost (USD)
Electrical wiring repair	$50–$250
Traction control solenoid replacement	$150–$500
ABS hydraulic control unit replacement	$600–$2,000
ABS control module replacement/programming	$700–$2,500

Related Trouble Codes

• C0001 – Traction Control Valve 1 Control Circuit
• C0002 – Traction Control Valve 2 Control Circuit
• C0003 – Traction Control Valve 3 Control Circuit
• C0035 – Left Front Wheel Speed Sensor Circuit
• C0040 – Right Front Wheel Speed Sensor Circuit

Frequently Asked Questions

What causes C0004?

Common causes include a faulty ABS hydraulic control unit, failed traction control solenoid, damaged wiring, corroded connectors, or poor electrical grounding.

Can low brake fluid cause C0004?

Low brake fluid is generally not the direct cause of C0004, although it can affect overall ABS performance and should always be checked.

Will clearing the code permanently fix C0004?

No. Clearing the code only removes it from memory. If the electrical or hydraulic fault still exists, the ABS module will detect it again and the code will return.

Conclusion

C0004 indicates an electrical fault in the Traction Control Valve 4 control circuit. Inspecting the ABS hydraulic control unit, wiring, electrical connectors, and control module is essential to restore proper ABS, traction control, and electronic stability system operation.