Seeing the AdBlue warning light on your dashboard can have several meanings. To act appropriately, it is important to understand the causes.
When the AdBlue warning light turns on, several causes may be at play. This liquid, essential for the operation of the SCR system (Selective Catalytic Reduction), helps reduce your vehicle's pollutant emissions. However, certain malfunctions can disrupt this system, triggering the warning light on your dashboard. It is therefore crucial to understand the possible reasons to react appropriately and avoid costly repairs.
But what does this warning light really mean ? Is it serious ? Can you turn it off yourself, or do you always need a mechanic ?
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Possible AdBlue-Related Malfunctions
The AdBlue system can be subject to various malfunctions, often indicated by the warning light on the dashboard. Here are the most common issues :
Warning Light Stays On
Sometimes, the warning light remains on even after refilling. This may be due to an insufficient amount of liquid (less than 5 liters) or an issue with the level sensor. In this case, it is recommended to check the level and reset the system if necessary.
AdBlue Crystallization
The liquid can crystallize when exposed to air or extremely low temperatures. These crystals can clog injectors or block certain parts of the tank, leading to SCR system malfunctions. Crystallization often occurs when the liquid overflows or is poorly stored.
Injector Issues
Injectors, crucial for the proper diffusion of the additive in the exhaust system, can become clogged due to crystallization or impurities in the liquid. A faulty or obstructed injector can hinder the system's function, resulting in improper emission reduction.
Tank Issues
Overfilling or overflowing the AdBlue tank can cause deformation due to excessive pressure or crystal formation. If the tank becomes deformed, replacement is often necessary, which can be costly.
Blocked Sensor
Level sensors can also malfunction. A blocked or defective sensor can send incorrect information to the system, falsely indicating an empty tank. This problem usually requires an electronic diagnosis for correction.
Electrical Issues
Electrical failures or communication errors between system components can also trigger the AdBlue warning light. A complete diagnostic is often needed to identify the exact cause.
How to Fix AdBlue Issues ?
To resolve these problems, various solutions exist depending on the malfunction. Here are the steps to correct the most common AdBlue faults :
- Warning Light Stays On : Ensure that you have added at least 5 liters of AdBlue. If the light persists, you may need to manually reset the system via the onboard computer or visit a mechanic.
- Crystallization : If crystallization occurs, clean the tank and affected injectors. You can also use an anti-crystallization additive when refilling. In severe cases, some parts may need replacement.
- Injector Issues : A deformed tank will need replacement. To prevent this, always respect the tank’s maximum capacity during refilling.
- Tank Issues : A deformed tank will need replacement. To prevent this, always respect the tank’s maximum capacity during refilling.
- Blocked Sensor : The level sensor may need cleaning or replacement. An electronic diagnosis can pinpoint the issue.
- Electrical Issues : Have a vehicle diagnostic performed to detect any electrical failures or necessary software updates. These actions can restore the AdBlue system’s proper function.
Why Does the Warning Light Stay On ?
If the warning light remains on despite refilling AdBlue, several causes may be involved :
Low AdBlue Level
The warning light may indicate a low AdBlue level, especially if you have added less than 5 liters. The system often does not recognize small quantities, requiring a sufficient refill to reactivate.
Faulty Level Sensor
The level sensor measures the AdBlue quantity in the tank. If defective, it may send incorrect information to the dashboard, keeping the warning light on even when the tank is full. A faulty sensor must be replaced.
SCR System Failure
The SCR system itself may be faulty. A malfunction in the injectors, catalyst, or other components can prevent proper emission treatment, causing the warning light to turn on. A thorough diagnostic is required to identify the problem.
Electrical or Software Issues
Software bugs or electrical failures can disrupt communication between the vehicle’s components. In this case, a system update or wiring check may be necessary.
Best Practices to Follow
To avoid AdBlue system malfunctions, adopt these best practices :
- Always add at least 5 liters of AdBlue to reset the system : This ensures the level is sufficient to disable the warning light and keep the system operational.
- Avoid refilling before the warning light turns on : Filling too early can lead to overflow and crystallization in the tank.
- Prevent overfilling : Overflows can cause crystal deposits in the tank and pipes, leading to costly malfunctions.
- Store AdBlue properly : Always keep AdBlue in its original container, away from sunlight and extreme temperatures, as improper storage can reduce its effectiveness.
- Use suitable equipment : When refilling, use specific tools such as funnels to prevent liquid contamination.
- Check AdBlue expiration date regularly : AdBlue has a limited shelf life (about one year). Using expired liquid can cause system malfunctions.
By following these guidelines, you can extend the lifespan of your AdBlue system and avoid expensive repairs.
Learn more
Here’s our article on the issues and best practices for handling AdBlue. If you have any advice or questions, feel free to share them in the comments.
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