SCR systems and AdBlue fluid are used in newer diesel vehicles to reduce nitrogen oxide emissions. This technology is especially common in vehicles that comply with the Euro 6 standard.
The SCR system doses AdBlue solution into the exhaust system, where, through a chemical reaction, it helps reduce the amount of harmful nitrogen oxides in the exhaust gases. In theory, this is an efficient and environmentally important system, but in practice, it often causes a number of problems for vehicle owners.
Although the SCR system is useful for reducing emissions, it is quite complex and sensitive to operating conditions. Faults can be caused by the AdBlue fluid itself, as well as by electronic or mechanical system components.
The most common causes of SCR / AdBlue problems:
AdBlue solution is sensitive to temperature and storage conditions. At low temperatures, it can thicken or freeze, and if stored incorrectly, it can lose quality. As a result, crystals may form in the system, clogging injectors, pipes, and other components.
An SCR or AdBlue system fault is usually indicated by a warning message on the dashboard. In some vehicles, the system may start counting down the remaining distance until engine start is blocked.
The most common symptoms:
If you notice these symptoms, it is important not to delay diagnostics. The longer the problem is ignored, the higher the chance that the fault will affect more system components.
The SCR / AdBlue system consists of many interconnected components: the AdBlue tank, pump, heating element, injector, NOx sensors, temperature sensors, catalyst, exhaust system, and ECU control logic.
Therefore, simply reading the fault code often does not reveal the real problem. The operation of the entire system must be assessed to determine whether the fault is mechanical, electrical, software-related, or caused by unsuitable fluid.
During SCR / AdBlue diagnostics, we check:
Only after such an inspection can we accurately determine which solution is most suitable for the vehicle.
After diagnostics, the most suitable solution can be selected based on the vehicle model, the nature of the fault, and the condition of the system.
1. AdBlue system repair
In some cases, it is enough to replace the faulty component: NOx sensor, pump, injector, heating element, or another system part. This is the factory solution, but SCR system repairs on some vehicles can be expensive.
2. System cleaning
If the problem is related to crystallization or blockage, certain parts of the SCR system can be cleaned. However, this solution does not always help, especially if the components are already damaged or the electronic part is not operating correctly.
3. SCR / AdBlue system software work
In some cases, SCR / AdBlue system software work may be required: fault analysis, control logic checks, adaptations, or ECU software corrections. Such work must be carried out responsibly, using professional equipment and in compliance with applicable technical and legal requirements.
At Diagnet™, we solve SCR / AdBlue problems systematically. First, we perform diagnostics, identify the real cause of the fault, and only then recommend the most suitable solution.
We perform:
Our goal is not to temporarily remove a warning, but to help find a reliable and technically justified solution.
If you see an AdBlue, SCR, NOx, or emissions system warning on the dashboard, if the vehicle limits power, or if it shows the remaining distance until engine start is blocked – do not delay.
Contact Diagnet™ at info@diagnet.lt – we will perform SCR / AdBlue system diagnostics, identify the cause of the fault, and offer the most suitable solution for your vehicle.
