An AdBlue error on Euro 6 diesels with SCR systems often leads to reduced power and a countdown of remaining starts. Ignoring it can stop the vehicle from starting.
What the AdBlue error means
The SCR system injects a urea solution (AdBlue) into the exhaust to reduce nitrogen oxides. When the control unit detects it is not doing so correctly (level, quality, dosing, NOx sensor), it flags the error and, by regulation, progressively limits power and counts remaining starts.
Symptoms
- "AdBlue error" or "Emission control system fault" message
- Countdown of starts or kilometres
- Reduced power
- Engine light on
Common causes
- Faulty NOx sensor or AdBlue pump
- Clogged or crystallised SCR injector
- Poor-quality, old or contaminated AdBlue
- Low tank level or faulty level sensor
- SCR control unit software errors
- Line heater failure in cold weather
What to do, in order
- Check the AdBlue level and top up if needed: sometimes the error is just a low level.
- If the message stays, do not wait for the lock: have the errors read in diagnosis.
- The technician finds the faulty component (NOx sensor, pump, injector, heater) and repairs or replaces it.
- Errors are cleared and the counter reset is verified.
Can I drive with the error?
Yes, as long as starts or kilometres remain, but with reduced power. A quick diagnosis is advisable: after the lock the car will not restart and you need a tow.
How much it costs
From €150-400 for a sensor or injector to €600-1,500 for the pump. The full picture is in how much it costs to repair the AdBlue system.
How MasterTuning helps
We read the real values of the control unit, not just the code: that is the difference between finding the faulty component and replacing parts by trial and error. After the repair we clear the error and check that it does not come back. Find the nearest centre or contact us.
Are you a workshop or a technician?
If you diagnose and work on SCR systems, or want to start working on ECUs, the tools are in our shop: Flex (OBD, Bench and Boot) and The Genius (stand-alone, with touchscreen), plus Korhex for protected ECUs. If you already have the equipment, you can get the modified files on mastertuningfile.com (credit price list).
AdBlue error: guides by make
Is your problem about a specific make? Read the dedicated guide: Peugeot and Citroën BlueHDi, Opel, Fiat, Mercedes BlueTEC, VAG group. Or the full overview of AdBlue problems by make.
Want an accurate diagnosis? Book a diagnosis at the nearest MasterTuning centre.
Frequently asked questions
What does the AdBlue error mean?
The SCR system has detected a fault or incorrect dosing: often reduced power and a countdown of starts.
Can I drive with the AdBlue error?
Yes while starts remain, but with reduced power; a quick diagnosis is advisable.
Does the AdBlue error go away if I top up?
If the cause was low level yes, after a few driving cycles. If the message stays, there is a fault to diagnose.
Why does power reduce with the AdBlue error?
Regulation requires progressively limiting power when the emission control system does not work, to push for repair.
