How To Reset Def Light On Mercedes Sprinter

Looking for tips on how to reset DEF light on Mercedes Sprinter?

Perhaps you notice that it is not working as it should. Or the reading is inaccurate. In either case, a simple reset is all you need to do.

Keep reading to learn how it’s done correctly on a Mercedes Sprinter.

how to reset def light on mercedes sprinter

DEF Light On Mercedes Sprinter

The Diesel Exhaust Fluid or DEF light is a warning system that alerts you when the DEF tank is close to being empty.

This impacts truck drivers more than those who drive passenger vehicles because of the danger it poses when the DEF is at its low point.

Basically, DEF is a mixture added to your engine. This minimizes environmental harm by mixing it with the diesel gas. Once it is time for you to add some more fluid, the DEF light blinks and glows.

Now, driving with the DEF light on is not exactly a good idea. This may mean trouble, which is dangerous for you and other people on the road.

If your vehicle requires a DEF, you need to check your manual to know what may happen if the light turns on as you run low. There are emission rules in the United States that prohibit diesel vehicles to be on the road when there is no DEF, especially when it is a requirement based on the exhaust design.

Thus, the warning light turns on when there is a need to add the DEF. If you ignore this signal for too long, the truck will reduce its power. And when the DEF level has gone far too low, it will prevent the engine from starting unless you have added the right amount of fluid.

Driving With A DEF Light Turned On

Before the tank runs empty, there is an alert on the dashboard that comes on, which is the DEF light. But if the DEF goes below 2.5 percent, the light will turn solid amber. It will then turn red if you still ignore it.

At this point, you really need to refill the DEF tank. Otherwise, the vehicle will go lower at about 5 miles per hour.

There are also cases when the light indicates some contamination to the fuel. But then the light will mean the same. It happens when you accidentally put the wrong fuel into the DEF tank.

Some instances that cause DEF fluid loss include driver error. Perhaps you forgot to inspect the DEF fluid when you check the fuel levels. Hence, this puts your engine at risk while damaging the DEF system, as well. Repair costs involved can be steep while at the same time leading to an unplanned downtime for you.

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Reset DEF Light On Mercedes Sprinter

If you are looking to reset the DEF light, then here are some things you can do.

But technically, the warning message should disappear once after you have refilled the tank. But if it still stays on, then you can do a reset.

Turn the key to the first position, which is the very first click. Wait for about 30 seconds before you turn the ignition off.

If this does not work, turn the ignition once, press the gas pedal and hold it until the glow comes on. Then, press back the gas pedal. The glow plug should flash a few times before stopping.

Turn the vehicle off and wait for about 10 seconds before you turn it on once more. Next, press the gas pedal a couple of times. On the second press, hold it until the plug turns back on. This should be able to reset the DEF light manually.

However, if this still fails, it is worth consulting an experienced technician to help you with this matter. This way, you can get the DEF light working as it should and prevent further problems in the future.


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