Reasons why the AdBlue light stays on after refilling the tank

The AdBlue light is a crucial indicator for diesel vehicles equipped with SCR technology, as its function is to reduce emissions of nitrogen oxides. However, it is common for this light to stay on even after refilling the tank. There are several reasons why this might happen, ranging from issues with the level sensor to the presence of contaminants in the fluid. Understanding these causes is vital to ensure the proper functioning of the exhaust gas treatment system and to avoid potential engine failures.

The AdBlue light can illuminate on the dashboard even after the tank has been filled. This can cause confusion and concern among drivers who seek to ensure their compliance with emission regulations. In this article, we will explore the most common reasons why this light may remain active, thus helping diesel vehicle owners better understand their exhaust gas treatment system and avoid larger issues.

Contamination of AdBlue fluid

One of the main reasons why the AdBlue light remains on is due to the contamination of the fluid. When AdBlue is mixed with water, dirt, or other contaminants, its effectiveness is compromised, which can lead to malfunctioning of the system. This results in the sensors detecting an anomaly and activating the warning light on the dashboard, alerting the driver to a potential problem that needs attention.

Use of low-quality AdBlue

Opting for low-quality AdBlue can be another reason behind the illuminated light. This fluid must be of high purity since impurities can clog the injectors and other components of the SCR system. If a non-certified product is used, it can lead to a series of failures, causing the AdBlue light to remain on even after a refill.

Issues with the level sensor

The level sensor of the AdBlue tank can also fail, triggering the warning light on the dashboard. When the sensor is not functioning correctly, it cannot detect the amount of fluid present and, therefore, may send a false signal to the system. This may be the result of an electrical or mechanical malfunction, which would require professional attention for a review and recalibration of the system.

System reset requirement

After refilling the AdBlue tank, the system may need to be reset. If the warning light remains on after filling, it is possible that the system has not recognized the new fluid. Resetting the system can be as simple as following the procedure specified by the manufacturer to reset the AdBlue warning light. It is important to consult the vehicle’s manual to perform this action correctly.

Mechanical problems in the SCR system

Mechanical issues within the SCR (selective catalytic reduction) system can also cause the AdBlue light to remain active. This includes failures in essential components such as the pump or the injectors that administer the AdBlue solution in the exhaust system. In cases where the system presents complex failures, it is recommended to consult a professional for an appropriate diagnosis.

Other factors to consider

Aside from the mentioned problems, it is also important to consider factors such as extreme temperatures, which can affect the performance of the AdBlue system. Prolonged exposure to very cold temperatures can freeze the AdBlue, and in excessive heat conditions, the fluid may evaporate or degrade more quickly. Both scenarios can trigger the warning light on the dashboard, indicating a potential problem with the system’s performance.

To avoid constant problems, it is essential to use high-quality AdBlue, maintain the system and its environment in optimal conditions, and be aware of any warning signals that may arise in the vehicle. Ultimately, having the right information and resources can help prevent unnecessary complications.

When the AdBlue light stays on despite having refilled the tank, it can be frustrating for diesel vehicle drivers. There are multiple reasons that can explain this situation, and it is crucial to address them to ensure the proper functioning of the SCR system, which reduces nitrogen oxide emissions.

One of the most common causes is contamination of the fluid. If the AdBlue has been contaminated with water, dirt, or other substances, it may lose its effectiveness. This means that, even though the tank is full, the system will not function as expected, which can lead to an alert on the dashboard.

Furthermore, using low-quality AdBlue can cause problems. This fluid must meet specific standards to avoid damage to the components of the SCR system. Therefore, it is vital to ensure that you use AdBlue that is 100% pure and certified.

Another reason why the light might stay on is a failure of the level sensor. If this sensor that monitors the AdBlue fluid is defective, it can send incorrect signals to the system, indicating that there is a problem even when the tank is full. In these cases, it is recommended to check the sensor or consult a professional.

Lastly, it should be noted that after refilling the tank, the system may require a reset for the light to turn off. In many vehicles, the reset process is simple, but if the light persists, it is advisable to visit a workshop for a more thorough review.