A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.
Possible causes
- The valve or its coil inside the ABS unit
- The ABS unit’s fuse or power supply
- The ABS unit’s ground: a corroded or loose ground bolt
- The ABS unit connector: corrosion, water
- Low voltage: a flat battery or corroded terminals
What you can do yourself
- ESP and traction control, and sometimes ABS, may not work. The brakes still work, but without electronic help — on slippery roads brake smoothly and don’t accelerate hard.
- If the brake pedal has become hard, soft or sinks, or the car brakes worse — don’t drive, call a tow truck.
- The traction control valves are inside the ABS (hydraulic) unit. First check the unit’s fuses, power and ground.
Stop and don’t drive on if:
- The red brake light is on, or the brake pedal feels soft or sinks
- The steering became very heavy, or the car pulls to one side when braking
OOleg’s tip: check the connector
Often the cause is simple — there is no contact in the connector (plug). Look at the connector from the back: remove the rubber seal and you will see whether a wire is corroded or has come off completely. Corrosion shows up as green deposits. Ideally, gently pull each wire towards you one at a time: a sound wire stays in place, while a corroded one simply comes off — it needs to be repaired.
Unplug and inspect connectors with the ignition off.
If the scan tool shows the code with a suffix after a dash (for example, C0031-1D), that’s the fault detail: 01 — general electrical failure, 1D — circuit current out of range, 29 — invalid signal, 2F — erratic signal, 62 — signal doesn’t match the others.
The explanation comes from the error code reference in the AvtoElektrik PRO app.