Discover the 2025 guide to AdBlue system problems: causes, symptoms, and solutions to avoid warning lights, errors, and blockages. Practical advice and certified AdBlue for your car.
In recent years, the AdBlue system has become indispensable on modern diesel engines.
Mandatory to comply with Euro 6 regulations, it drastically reduces nitrogen oxide (NOx) emissions , protecting the environment and ensuring more stringent approvals.
But not all drivers really know how it works , what problems it can cause and how to manage it well .
✅ Warning lights that come on suddenly.
✅ SCR failure messages.
✅ Power limitations or start block.
This 2025 guide was created to explain everything about the AdBlue system clearly and comprehensively:
✔️ How it works.
✔️ What are the causes of the most common problems?
✔️ How to recognize the symptoms.
✔️ Practical solutions and maintenance tips.
Because intelligent AdBlue management is essential to avoid hassles, unnecessary expenses and travel with peace of mind.
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✅ How the AdBlue system really works
AdBlue is a 32.5% aqueous urea solution that does not mix with diesel fuel.
✅ It is injected into the hot exhaust gases, downstream of the engine.
✅ Here it turns into ammonia.
✅ Reacts inside the SCR (Selective Catalytic Reduction) catalyst .
✅ Transforms NOx → harmless nitrogen and water vapor.
⭐ Result?
✔️ Nitrogen oxide emissions reduced by up to 90%.
✔️ Car compliant with Euro 6 and future regulations.
✔️ Greater respect for the environment.
Read Also: What is the best AdBlue on the market?
🛠️ Key components of the SCR system
✅ AdBlue tank
✔️ Variable capacity (10–20 litres).
✔️ It must be topped up regularly.
✅ Pump and pipes
✔️ They transport the liquid to the injector.
✔️ They must be perfectly sealed to avoid crystallization.
✅ AdBlue injector
✔️ Sprays the precise amount of solution into the exhaust gases.
✔️ Must withstand high heat and deposits.
✅ SCR management control unit
✔️ Check the amount and timing of the injection.
✔️ Communicates with the engine control unit.
✅ SCR Catalytic Converter
✔️ The heart of catalytic reduction.
✔️ Transforms harmful gases into inert components.
⚠️ Why the AdBlue system can cause problems
Many people think that AdBlue is “just a liquid to top up every now and then”.
It is not so.
This is a complex, sensitive and expensive system.
✅ Fluid quality, maintenance and climatic conditions can cause serious problems .
✅ The regulations are strict: if the system doesn't work → the car can limit power or even prevent starting.
Read Also: What Happens if My Diesel Car Runs Out of AdBlue?
✅ Most common AdBlue system problems
⭐ 1️⃣ Low or exhausted level
⚠️ The most banal but frequent cause.
✔️ AdBlue light on.
✔️ “Refill AdBlue” message.
✔️ Vehicle stalls after a limited number of starts if not topped up.
⭐ 2️⃣ Crystallization of the liquid
✔️ AdBlue crystallizes below -11°C.
✔️ Risk of blocked pipes and injectors.
✔️ This problem is more common in cold areas or in cars that have been left standing for a long time.
⭐ 3️⃣ Poor quality or contaminated AdBlue
❌ Uncertified or poorly stored canisters.
✔️ Contamination → crystals → clogged injectors.
✔️ Sensors that do not read the concentration correctly → errors in the control unit.
⭐ 4️⃣ Electronic malfunctions
✔️ Faulty level sensors.
✔️ SCR control unit faulty.
✔️ Incorrect communication with the engine ECU.
⭐ 5️⃣ AdBlue injector clogged or defective
✔️ Uneven or blocked spray.
✔️ Crystal deposits that reduce efficiency.
⭐ 6️⃣ Leaks from the tank or pipes
✔️ AdBlue is corrosive to untreated metals.
✔️ Leaks → waste → system failure.
Read Also: What is Automotive Urea? Everything You Need to Know About AdBlue
🔎 Most common symptoms
✅ AdBlue or SCR warning light on the dashboard.
✅ “Limited remaining starts” message.
✅ Engine power limitation.
✅ Starter block after the start counter.
✅ Abnormal AdBlue consumption.
✅ Odor or stains under the car.
Read Also: ADBLUE SYSTEM ERROR MESSAGES: WHAT THEY MEAN AND HOW TO FIX THEM
💡 Practical tips to avoid problems
⭐ Use only ISO 22241 certified AdBlue.
➡️ Avoid anonymous or unsealed containers.
⭐ Check the level regularly.
➡️ Don't wait for the final warning.
➡️ It's best to top up before long journeys.
⭐ Avoid prolonged storage.
➡️ AdBlue absorbs moisture.
➡️ An opened container degrades in a few months.
⭐ Protect the system from frost.
➡️ Many vehicles have built-in heating.
➡️ Avoid leaving your car parked outside for weeks in winter.
⭐ Perform regular maintenance.
➡️ Specialized workshops can clean injectors and pipes.
➡️ ECU diagnosis for any errors.
⭐ Don't ignore the spies!
➡️ A faulty SCR system can limit power or prevent starting by law.
🏅 Recommended brands of certified AdBlue
✅ BASF – OEM quality, wide industrial use.
✅ GreenChem – Widespread distribution at service stations.
✅ TotalEnergies AdBlue – Excellent availability, consistent quality.
✅ Magneti Marelli AdBlue – Guaranteed purity, compliant with ISO 22241.
Recommended Product: Arexons 9655 - AdBlue Additive: Keep Your Vehicle's SCR System Efficient and Clean
✅ 📌 Important note
👉 At Autoricambi Tritella you will only find certified AdBlue and compatible accessories .
✅ Selected products.
✅ Technical support and advice on your model.
✅ Quality and safety guarantee.
Because choosing the right AdBlue isn't a minor detail: it's an investment in the health of your engine and respect for the environment.
🤝 Why rely on a professional
An experienced spare parts dealer or mechanic:
✅ It can recognize OEM codes and compatibility.
✅ Check the quality of the product.
✅ Avoid contamination or refill errors.
✅ It explains how to manage the SCR system correctly.
➡️ It's not just a seller: it's a partner who protects your mobility and the environment.
Read Also: How much does it cost to change the AdBlue tank?
🔗 Want to learn more?
👉 Read our guide to recommended additives for BlueHDi and modern diesels to keep your engine clean and efficient.
✅ Conclusion
The AdBlue system is not an optional extra: it is a strategic component for modern diesel engines.
✅ Reduces harmful emissions.
✅ Keeps your car compliant with regulations.
✅ Requires proper attention and maintenance .
✔️ Use only certified AdBlue.
✔️ Check the level regularly.
✔️ Trust those who really know your vehicle.
Because your safe and sustainable mobility starts with informed choices. 💧🚚
2 comments
Angelo Casnici
Grazie per le risposte che attendo con grande ansia
Avendo già avuto problemi con la mia precedente 3008
Angelo Casnici
Mi riferisco all’additivo da inserìre nel serbatoio adblue
Per cortesia ditemi le dosi necessarie in relazione a un litro di adblue e se posso mettere l’additivo già nel fustino dell’ adblue
Per cortesia ditemi cosa posso fare per capire se è in corso una rigenerazione del FAP e quindi non spegnere il motore