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 left and right sensors are swapped
- A bearing with a magnetic ring was fitted the wrong way round: the ring must face the sensor
- A sensor for a different model was fitted
What you can do yourself
- With this fault ABS usually switches off: the ordinary brakes still work, but without ABS the wheels can lock. Brake smoothly and leave a bigger gap, especially on slippery roads.
- If the code appeared after a hub or bearing replacement or suspension work, first check that the sensor and connector are in place and the wire isn’t pinched.
- A scan tool’s live data shows each wheel’s speed: while driving, this wheel should read the same as the others.
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
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.