Brakes, ABS and stability control
C codes: brakes, ABS, the stability system and its sensors. Ordinary OBD-II does not read them on every car — but knowing what a code you were told in the workshop means is always useful.
17 codes in this section, 17 with a guide
What it usually turns out to be
- Wheel speed sensors live at the hubs: dirt, salt and a chafed wire are the most common cause.
- If the light came on after a bearing or wheel change, the sensor was almost certainly disturbed.
- A disagreement between wheels starts with tyre pressures and sizes, not with electrics.
C0031Left front wheel speed sensor malfunctionguideC0034Right front wheel speed sensor malfunctionguideC0035Wheel speed sensor — the number is read differentlyguideC0037Left rear wheel speed sensor malfunctionguideC003ARight rear wheel speed sensor malfunctionguideC0040C0040: brake pedal switch in the standard, front right wheel at GMguideC0044Lateral acceleration sensor malfunctionguideC0045Wheel speed sensor — no signal (rear left at GM)guideC0050Wheel speed mismatch (rear right wheel at GM)guideC0051Steering angle sensor malfunctionguideC0061ABS hydraulic unit valve malfunctionguideC0110ABS pump motor circuit malfunctionguideC0121ABS valve circuit malfunctionguideC0196Yaw rate sensor malfunctionguideC0561Stability control disabled by another moduleguideC1095ABS pump motor does not reach operating modeguideC1145Wheel speed sensor — intermittent signal, usually a corroded connectorguide
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Other sections
Fuel and air metering, general 33Intake measuring sensors 17Oxygen sensors 19Throttle and accelerator pedal 15Mixture: lean and rich 11Fuel and air metering: injectors 25Ignition system and misfires 29Exhaust gas recirculation (EGR) 7Secondary air injection 3Catalytic converter 4Canister and purge valves 9Fuel vapour leaks 7Fuel level in the tank 4Diesel particulate filter 6Idle and auxiliary systems 22Control module and its circuits 21Transmission 17Communication between modules 20Body, airbags and lighting 12