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 tone ring or the bearing’s magnetic ring: a crack, dirt, stuck-on metal shavings, bearing play
- The sensor isn’t seated properly: too big a gap to the ring, or rust under the sensor
- The ring was knocked or damaged during axle or driveshaft work
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.
- Check the tone ring or the bearing’s magnetic ring: cracks, damaged teeth, stuck-on metal shavings. Don’t clean a magnetic ring with a magnet.
- 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.