How to Clear AdBlue Warning in Mercedes Sprinter?

Mercedes Sprinter is perhaps the most in-demand light commercial van out there…

You won’t find a van as powerful and reliable as Sprinter. Not just efficiency―the model is also known for its minimal ecological footprint… thanks to the advanced emissions control features it comes equipped with. The way it deals with NOx emissions is particularly impressive. Today’s blog post is about AdBlue…

What Is AdBlue and Why Does It Matter?

Before diving deep into the topic, it is important that you know a few facts about AdBlue.

• Vehicles with SCR technology relay on this fluid to eliminate oxides of nitrogen in exhaust emissions… so they can meet the Euro 6 emission standard.
• It is essentially a high-purity urea solution… with a 32.5% urea and 67% deionised water.
• SCR or Selective Catalytic Reduction system sprays this solution through a set of injectors to convert reactive NOx gases in the exhaust emissions into neutral N2 and water.

The chemical reactions that happens inside the SRC are as follows:

4NO + 4NH3+ O2 --> 4N2 + 6H2O

2NO2 + 4NH3 + O2 --> 3N2 + 6H2O

• Although this solution is quite effective at neutralizing harmful oxides of nitrogen, it has a drawback. It will freeze… as soon as the environmental temperature drops below -11O C.
• To prevent something like that from happening, the SRS system in some models come equipped with a heater.
• Just so your know… AdBlue is a brand name for a specific type of Diesel Exhaust Fluid. There are all sorts of other such fluids available in the market.

Why You Might Get an AdBlue Warning

If your Mercedes Sprinter displays AdBlue warning light, it could be due to one of the following reasons:

#1- AdBlue level is below minimum

When was the last time you checked the AdBlue level in your Sprinter? We get it… you were caught up with your routine tasks and forgot to keep track of the diesel exhaust fluid level in your vehicle. It happens. Your AdBlue warning might be on because there is not sufficient solution left in the tank to support the SRC system’s operation.

#2- Defective sensor

Or… perhaps the sensor responsible for monitoring the AdBlue level in your Sprinter has malfunctioned and is sending erroneous data, resulting in the illumination of the warning indicator. Another possibility is that the sensor’s contact with the onboard computer has been cut off, probably due to a frayed wire. And this disruption has resulted in the illumination of the warning indicator.

#3- Fluid contamination

Accumulation of dirt, debris, and other foreign elements in AdBlue can clog the injectors and SCR catalyst. As a result, the flow of urea solution into the exhaust will be obstructed and NOx emission will skyrocket. This may prompt the onboard computer of your Mercedes to activate the AdBlue warning… so that the driver can be alerted of the issue.

#4- Not using the right type of fluid

How effectively the Selective Catalytic Reduction system in your Mercedes Sprinter will be able to do its job depends on the type of diesel exhaust fluid used. If you don’t use the recommended type of urea solution in your Sprinter’s SCR, it can damage the system and trigger the AdBlue warning. Go through the owner’s manual before selecting any such fluid for your vehicle.

#5- Injector malfunction

Clogged or defective injectors can also set off the AdBlue warning in your Mercedes Sprinter. If you want your Sprinter’s SCR system to function smoothly and eliminate exhaust emissions in the most efficient way possible, it is important that you ensure the upkeep of the injectors the system relies on for spraying urea solution.

#6- Frozen AdBlue system

If the heater installed in your Mercedes’ SCR system is not functioning the way it is meant to… the urea solution stored in the tank may freeze. This may activate the AdBlue warning. The warning may also come on if there is something wrong with the NOx sensor installed in the exhaust system.

How to Clear the Warning

Step #1- Top up the AdBlue tank. If your Sprinter’s AdBlue light is on, this is the very first thing that you should do. Consider topping up the tank if there is not enough fluid left to support the SCR system operation.

Step #2- Fix the glitch in system... if there are any. Check the injectors and other important parts of SCR system, repair/replace any components that are found to be defective.

Step #3- To clear the error code... you can use an OBD-II scanner. It’s quite a handy tool and can be used for various purposes, including clearing the AdBlue warning.

Step #4- Try to reset the warning via 'Service Menu'. In some Sprinter models, AdBlue warning can be cleared through the service menu. Check the vehicle’s manual and proceed accordingly.

In Conclusion

• Don’t be panicked by sudden appearance of AdBlue warning in your Sprinter.
• Find out what triggered the alert. Fix the issue before it turns into an expensive repair.
• Information we have shared in this blog post might help you in this regard.

Sprinter Gurus is one of the most sought-after Sprinter repair & service facilities located in Norcross, GA. The technicians working at our facility have years of experience in taking care of Sprinter vans.