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
- Open wire or poor contact in the connector
- AdBlue pump or supply valve
- Blown SCR/AdBlue circuit fuse
- ECU (rarely)
What you can do yourself
- Check the AdBlue system fuses and relays (labels SCR, DCU, Urea, DEF — depending on the brand).
- Inspect the AdBlue pump connector (usually in or next to the tank) for corrosion and water.
- If the fault isn’t fixed, after a while the engine will limit power or speed, and some cars won’t allow a restart. This is protection required by Euro 5 and Euro 6 rules: drive calmly to a service centre without delay.
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.
The explanation comes from the error code reference in the AvtoElektrik PRO app.