How to Reset DEF Light on Mercedes Sprinter – 5 Easy Steps

How to reset DEF light on Mercedes Sprinter is an essential aspect to comprehend. The DEF system is critical to the vehicle’s functionality, and any problems with it can cause the DEF warning light to illuminate on the dashboard.

Reset DEF Light on a Mercedes Sprinter

Don’t be alarmed if you run into this problem. This article will walk you through the process of resetting the DEF light on your Mercedes Sprinter.

How to Reset DEF Light on a Mercedes Sprinter

To reset DEF light on a Mercedes Sprinter you can refill the DEF tank and start the vehicle to check. After that, you can use an obd2 scanner to reset or simply disconnect the battery. Finally, you have to check the system to verify.

1. Refill the DEF Tank

The first step in resetting the DEF light on a Mercedes Sprinter is to refill the DEF tank. The DEF tank is a separate tank located next to the fuel tank, with a blue cap to distinguish it from the fuel cap. To minimize emissions, the DEF system injects a tiny quantity of DEF fluid into the exhaust stream.

When the DEF light illuminates, it indicates that the DEF tank is low and that the DEF fluid has to be replaced. It is critical to refill the DEF tank before it runs out of fluid, as this can cause major engine damage.

DEF fluid and a funnel are required to replenish the DEF tank. DEF fluid is widely accessible at most vehicle parts stores, and you may save money by purchasing it in quantity. It is critical to use the correct type of DEF fluid, as indicated in the vehicle’s owner’s handbook.

Employing the incorrect type of DEF fluid might harm the DEF system and cause the DEF light to remain on. Open the DEF tank cap and insert the funnel once you have the DEF fluid and funnel.

Pour the DEF fluid into the tank slowly, taking care not to spill any of it. Because the tank has a maximum capacity, it is critical not to overfill it. Overfilling the tank might cause DEF fluid to flow out and harm the paint of the car. After filling the DEF tank, reinstall the cap and make sure it’s properly closed.

2. Start the Vehicle

When refueling the DEF tank, the vehicle’s computer must identify the new fluid level and reset the DEF light. Starting the car is an important stage in this procedure. To begin, turn the ignition key to the on position and wait a few seconds.

Refueling the DEF Tank

If the system detects a new fluid level in the tank, the vehicle’s computer will run a self-check, and the diesel exhaust fluid light should switch off. If the DEF light does not turn off after starting the vehicle, there may be additional problems with the DEF system that must be resolved.

It’s crucial to know that after starting the car, the computer may take a few minutes to reset the DEF light. Don’t be alarmed if the DEF light does not turn off immediately after starting the car. Let the car idle for a few minutes to allow the system to reset itself.

If the DEF light remains on after a few minutes of idle state, there may be other problems with the DEF system that must be addressed.

3. Use an OBD2 Scanner

If the DEF light on a Mercedes Sprinter does not turn off after replenishing the add DEF tank and starting the vehicle, utilizing an OBD2 scanner to reset the system might be a handy alternative. An OBD2 scanner is diagnostic equipment that can read and clear error codes in the computer system of a car.

To reset the DEF light with an OBD2 scanner, first, obtain an OBD2 scanner and attach it to the vehicle’s OBD2 port. The OBD2 port is often found on the driver’s side of the car under the dashboard. After connecting the OBD2 scanner to the car, turn the ignition key to the on position but do not start the engine.

To read and clear the error codes in the vehicle’s computer system, follow the instructions on the OBD2 scanner. Check for any DEF system-related codes and clear them if required. Start the car after clearing the error codes and wait for the system to reset itself.

If the system detects a new fluid level in the tank, the DEF light should switch off. Using an OBD2 scanner is a more complicated technique for resetting the DEF system and should be done only if you are familiar with diagnostic tools.

4. Disconnect the Battery

Another option for resetting the system is to disconnect the battery. This step should be tried only if you have prior expertise dealing with automotive electronics since it can be deadly if not done correctly.
Turn off the ignition and remove the key from the ignition before disconnecting the battery. Depending on the model of your Sprinter, look for the battery in the engine compartment or under the driver’s seat.

Disconnect the Battery

Loosen the negative terminal clamp on the battery using a wrench or socket and carefully remove the cable from the battery. Let the vehicle’s computer system reset by disconnecting the battery for at least 15-20 minutes.

During this time, all DEF-related error codes should be removed from the system’s memory. Reconnect the negative connection to the battery after 15-20 minutes and tighten the clamp using a tool or socket.
Avoid overtightening the clamp, since this might harm the battery or strip the clamp’s threads. Lastly, start the car and wait for the system to reset. If the system detects a new fluid level in the tank, the DEF light should switch off.

5. Check the System

Once you’ve performed the preceding procedures to reset the DEF light on your Mercedes Sprinter, you should inspect the system to confirm that the warning light remains off and the system is working properly.
This phase consists of a short test drive to ensure that the system is functioning properly. Begin by taking a short drive in the car, preferably on a highway or other open route where you can attain and hold a constant pace for a few minutes.

Inspect the System to Confirm Warning Light

Maintain vigilance on the dashboard to ensure that the DEF warning light does not illuminate again. If this occurs, you may need to repeat the preceding procedures or take the car to a mechanic for additional evaluation.

After the test drive, if you are confident that the DEF system is working correctly and the warning light is off, you can resume regular driving. But, it’s critical to keep an eye on the vehicle for any more warning lights or messages that may arise, since they might be an indicator of a more serious problem that necessitates expert assistance.

Can Resetting the DEF Light Fix Starting Problems in a Mercedes Sprinter?

When encountering starting problems in a Mercedes Sprinter, resetting the DEF light may not necessarily fix the issue. While the DEF system can occasionally cause starting problems, it is essential to address any underlying problems first. Common starting issues in Mercedes Sprinters may stem from a faulty battery, fuel delivery problems, or malfunctioning components within the ignition system. Consulting a professional mechanic is advisable to accurately diagnose and resolve these mercedes sprinter common starting issues.

Can the Same Steps Be Used to Reset the Check Engine Light on a Mercedes Sprinter?

Resetting the check engine light on a Mercedes Sprinter requires specific methods, not the prius check engine light reset methods. Consult the vehicle’s manual for accurate instructions. Be cautious as the light could indicate an underlying issue. Seek professional help if needed. Maintain your Sprinter’s performance by regular maintenance and addressing any potential problems promptly.


Resetting the DEF light on your Mercedes Sprinter is a simple task that you can complete on your own now that you have learned how to reset the DEF light on Mercedes Sprinter.

To sum it up, the main ideas we’ve discussed are:

  • The first step in resetting the DEF light is to refill the DEF tank, which entails pouring DEF fluid into the tank until it reaches the required level.
  • The second step is to start the vehicle, which allows the system to reset and the warning light to turn off if the DEF tank has been replenished.
  • If the warning light remains on after replenishing the DEF tank and restarting the vehicle, utilizing an
  • OBD2 scanner or disconnecting the battery are possible remedies.

Inspect the system regularly to verify that it is functioning properly and that your Mercedes Sprinter is running smoothly while reducing emissions for a cleaner environment.

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