C0029 Code – ABS Brake System Fault

The C0029 Diagnostic Trouble Code (DTC) is a manufacturer-specific chassis code used by the Anti-lock Braking System (ABS). Unlike generic OBD-II powertrain codes, the definition of C0029 varies between vehicle manufacturers. It is commonly associated with an ABS wheel speed sensor circuit, brake pressure control, or an internal ABS hydraulic unit fault.

Common Symptoms

• ABS warning light ON.
• Brake warning lamp illuminated.
• Traction Control (TCS) and Stability Control (ESC) disabled.
• ABS intervention unavailable during emergency braking.

Possible Causes

• Faulty ABS wheel speed sensor.
• Damaged wiring harness or poor electrical connection.
• Corroded connector terminals.
• Damaged tone ring or wheel bearing.
• Brake pressure control or hydraulic unit malfunction.
• ABS control module failure.
• Low battery voltage or charging system problem.

How to Diagnose

1. Read all ABS diagnostic trouble codes.
2. Review Freeze Frame and Live Data.
3. Compare wheel speed sensor values while driving.
4. Inspect the wiring harness and connectors.
5. Check the tone ring, wheel bearing, and hydraulic unit if applicable.
6. Clear the code after repairs and perform a road test.

C0029 Code Meaning by Vehicle Brand

Vehicle Brand	Typical Meaning
Subaru	Manufacturer-specific ABS brake system fault.
GM (Chevrolet, GMC, Cadillac, Buick)	Brake Pressure Control or ABS Hydraulic System Fault (varies by model).
Chrysler / Dodge / Jeep / RAM	Manufacturer-specific ABS system fault.
Toyota / Lexus	ABS actuator or brake pressure control fault depending on model.
Ford / Lincoln	Manufacturer-specific ABS diagnostic code.
Honda / Acura	Manufacturer-specific ABS control system fault.
Hyundai / Kia	Manufacturer-specific brake control system fault.
Volkswagen / Audi / Skoda / SEAT	Manufacturer-specific ABS hydraulic or electronic control fault.

Related DTCs

• C0027
• C0028
• C0030
• C0035
• C0040

Important: The meaning of C0029 differs between manufacturers. Always consult the factory service information or a professional diagnostic tool to identify the correct definition for the specific vehicle before replacing any ABS components.