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 ABS pump motor fuse (usually a big one, in the under-hood fuse box) or its socket
- The ABS unit’s ground: a corroded or loose ground bolt
- The ABS unit connector: corrosion, water
- The pump motor or its relay inside the ABS unit
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 ABS pump motor fuse and its socket, then the ABS unit’s ground and connector: corroded contacts are a common cause.
- Check the battery and alternator: the pump motor draws a high current and may not start at low voltage.
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.