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
- An open in the sensor supply wire
- The sensor connector at the brake pedal
- The control unit itself
What you can do yourself
- Without this sensor’s signal cruise control, ESP and brake assist may not work, and on some cars the brake lights too.
- Check that the brake lights work: ask someone to watch while you press the brake. If they don’t light, drivers behind won’t see you braking — fix it as soon as possible.
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.
The explanation comes from the error code reference in the AvtoElektrik PRO app.