The AdBlue system, found on many Euro 6 diesel vehicles, is designed to reduce nitrogen oxide (NOx) emissions. However, when a malfunction occurs or an AdBlue error message appears on the dashboard, it's crucial to understand what's happening and how to intervene to avoid more serious problems.
🔧 WHAT IS THE ADBLUE SYSTEM AND HOW DOES IT WORK?
AdBlue is a urea-based solution injected into the exhaust system to convert NOx into nitrogen and water vapor. The system is managed by a dedicated control unit that monitors:
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The amount of AdBlue injected
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The liquid level in the tank
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The quality of the liquid
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Correct functioning of the pump and injectors
⚠️ THE MAIN ERROR MESSAGES RELATED TO ADBLUE
Here are the most common messages that may appear on your car's display:
1. "Refill AdBlue: engine cannot be started in XXX km"
➡️ What it means: The AdBlue level is low and needs to be topped up as soon as possible.
✅ Solution: Refuel with an ISO 22241 certified fluid.
2. "AdBlue system error" or "Check AdBlue system"
➡️ What it means: There is a fault in the control unit, injector or sensors.
✅ Solution: A diagnosis with a professional tester is required to identify the error (e.g. P20E8, P204F, P207F).
3. "Insufficient AdBlue quality"
➡️ What it means: The liquid inserted is not compliant or has expired.
✅ Solution: Empty the tank and replace with high-quality AdBlue.
4. "AdBlue system blocked. Engine cannot be started."
➡️ What it means: Maintenance has been neglected for too long or there is a serious fault.
✅ Solution: An authorized workshop is required to unlock the control unit and reset the system.
5. Engine warning light on along with the AdBlue message
➡️ What it means: The problem may be linked to the SCR (Selective Catalytic Reduction) system.
✅ Solution: A complete diagnosis with reading of fault codes (e.g. P2200, P229F, P2BA9) is required.
🛠️ HOW TO RESET THE ADBLUE SYSTEM
In some cases, the system resets automatically after refueling, but in the presence of more complex errors it may be necessary to:
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Use a professional OBD tool
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Update the engine control unit (ECU)
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Reset workshop error parameters
⚠️ Please note : Manual reset alone will NOT fix the problem if there is a mechanical or electronic fault.
🚘 BRANDS MOST INVOLVED IN ADBLUE ERRORS
AdBlue error messages are most commonly found on cars such as:
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Peugeot/Citroën (e.g. P20E8 BlueHDi error)
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Renault (Clio, Captur, Megane dCi)
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Volkswagen/Audi/Seat/Skoda (TDI engines with SCR)
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BMW (series with Euro 6 diesel engines)
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Mercedes-Benz (models with BlueTEC)
🧊 SOME PRACTICAL TIPS
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Always refuel with original or ISO 22241 certified AdBlue
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Avoid traveling with the level too low
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Do not store AdBlue for too long: it expires after approximately 12 months.
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In winter, the liquid may crystallize if exposed to temperatures below -11°C
❓ FREQUENTLY ASKED QUESTIONS
🟠 Where can I buy reliable AdBlue?
You can purchase certified AdBlue at Autoricambi Tritella , a car parts dealer with fast delivery and technical assistance.
🟠 How much does it cost to repair an AdBlue system fault?
It depends on the cause: a sensor can cost €50-150, while a pump or injector can even exceed €500.
🟠 Can I deactivate the AdBlue system?
No. It's illegal and carries a penalty of annulment and heavy fines. It also compromises the vehicle's warranty and approval.
🔚 CONCLUSIONS
The AdBlue system is essential for complying with environmental regulations, but when errors or malfunctions occur, it's important to intervene promptly. Ignoring an AdBlue error message can lead to vehicle immobilization. To avoid breakdowns and ensure safe travel, rely on professionals and always use quality products.
