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
- Internal control unit fault
- Poor ground or power supply to the control unit
- Moisture or corrosion in the unit or its connector
What you can do yourself
- First check the battery, the terminals and the control unit ground: with a poor supply the unit makes errors.
- If the code stays, the unit is checked and repaired by a specialist. Don’t rush to buy a new unit: many control unit faults can be repaired.
Stop and don’t drive on if:
- The Check Engine light is flashing
- The temperature gauge is in the red or the overheating light is on
- The red oil pressure light is on
- Smoke from under the bonnet, a burning or petrol smell
- Strong jerking, knocking from the engine, or the car barely moves
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.
OOleg’s tip: don’t pressure-wash the engine
Never wash the engine with a Kärcher (a pressure washer), steam or anything like that — there’s a special foam cleaner for that. Once the rubber seals in the connectors have dried out, moisture gets inside and the sensor connectors and the computer (ECU) connector rot.
The explanation comes from the error code reference in the AvtoElektrik PRO app.