How To Fix Mercedes-Benz Sprinter AdBlue Heater Element Failure

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Mercedes-Benz cars powered by diesel, such as the Sprinter, are technological marvels. They achieve all the power and performance of a diesel engine while eliminating the majority of the emissions associated with that fuel. This is because the Mercedes Sprinter and similar cars use a system known as DEF (Diesel Exhaust Fluid).

When driving a Mercedes with a diesel engine, you'll need regular maintenance to keep it running at its best. The first step is to make sure your Diesel AdBlue fluid is always full, and the second is to do regular inspections to ensure everything is in working order.

To ensure the quality of how your car functions, hard parts and components must be serviced or replaced regularly. The AdBlue Tank, Heating Element, and, in extreme circumstances, changing your Diesel Particulate Filter when it is clogged are some of the most regularly replaced items.

This article will explain the DEF system, why the DEF heater element may be malfunctioning, and what to do if this critical component fails.

Table Of Content

  1. What is diesel exhaust fluid?
  2. The Mercedes Sprinter DEF heater element
  3. Troubleshooting Mercedes-Benz Sprinter heater element failure
  4. Adblue tank heater element replacement for Mercedes-Benz Sprinters
  5. Procedure for replacing AdBlue tank heater element for Mercedes-Benz Sprinter
  6. Conclusion

1. What Is Diesel Exhaust Fluid?

DEF stands for diesel exhaust fluid, as the name implies. In addition to the normal fluids like oil, antifreeze, transmission fluid, brake fluid, and, of course, fuel, diesel vehicles require a unique fluid.

Mercedes Benz Sprinter van

It has to react with hazardous nitrogen oxides in the vehicle's exhaust, and it's made up of a specific mixture of urea and water (32.5% urea and 67.5% water, to be exact). Before being released into the environment, this reaction transforms the hazardous compounds into ordinary nitrogen and water.

This technology reduces pollutants and helps the globe stay a little greener, as typical diesel exhaust is a significant pollutant.

The DEF is kept in an external tank with its heater element, which is designed to keep it warm throughout the winter months. What's more, for nearly ten years, most diesel vehicles have been required by law to use DEF to decrease emissions. As a result, if your DEF heater isn't operating properly for any reason, you shouldn't disregard it.

2. The Mercedes Sprinter DEF Heater Element

DEF is stored in an external tank and sprayed into the exhaust pipe just before the selective catalytic converter to react with nitrogen oxides. However, because it's kept outside, it's vulnerable to the elements.

DEF heater element

DEF has a freezing value of 12 degrees Fahrenheit (-11 degrees Celsius), and it cannot be injected into the exhaust if it is frozen. DEF tanks include a specific heater element that keeps the fluid warm enough to stay liquid to prevent this from happening. This heater, like all mechanical parts, can burn out with time.

Of course, if it's a warmer time of year or you live somewhere where the temperature never drops below 12 degrees Fahrenheit, this isn't a problem. However, in the winter, the DEF is at risk of freezing. This would not only reduce engine performance, but it would also allow harmful substances to be released into the atmosphere. If the DEF is not properly injected, your car may go into limp mode or refuse to start altogether.

DEF heater element

In most circumstances, your vehicle will notify you before this becomes a significant problem by putting on a warning light, but it's always a good idea to double-check for yourself if the sensor isn't operating properly.

3. Troubleshooting Mercedes-Benz Sprinter Heater Element Failure

First and foremost, check the AdBlue level and replenish it if necessary. AdBlue fluid can be purchased from any Mercedes dealer, or a generic Diesel Exhaust Fluid can be purchased at auto parts stores or gas stations.

DEF tank

If there is a problem with the system, make sure to check the following:

  • Temperature sensor readings upstream of the SCR catalytic converter
  • Upstream of the SCR catalytic converter values from the NOx sensor control unit
  • NOx sensor control unit values downstream of the SCR catalytic converter
  • Quality and amount of DEF in the AdBlue tank
  • AdBlue injection valve and delivery pump
  • Amount of AdBlue metering
  • Check for leaks visually.

4. Adblue Tank Heater Element Replacement For Mercedes-Benz Sprinters

If you own a diesel Mercedes-Benz BlueTec, you may be met with the check engine light one day, which is usually caused by a fault code like 20BE1B, 20BD1B, P20B8, P20E8, P20BD, P20BE, P20B9.

Heater element

A defective Mercedes Diesel Exhaust Fluid (DEF) heater element or DEF pump is the most common cause of these problems. When the heater element in the AdBlue tank fails, the only way to fix it is to get it replaced with a new one.

What Will You Require To Replace A Faulty AdBlue Tank Heater Element?

Heater for Mercedes DEF

  • A Mercedes DEF heating element from the factory.

Basic equipment

  • 3 / 8 " ratchet
  • Socket size: 10mm
  • Screwdriver
  • Hammer
  • 3 / 8 "Socket E14
  • Hex bit with a diameter of 4mm

Replacement heater element

5. Procedure For Replacing AdBlue Tank Heater Element For Mercedes-Benz Sprinter

Step 1

Allow the Mercedes to cool down by parking it on level ground.

Step 2

Identify the DEF tank. It is located below the sliding door on the passenger side of Sprinter vans. The BlueTec tank is found in the trunk or engine compartment in a select few vehicles.

DEF tank location

Step 3

Remove the two brackets holding the DEF tank to the body.

Step 4

While you separate all the hoses and wires from the DEF tank, have a helper keep it upright.

Step 5

Disconnect all electrical connectors and hoses from the DEF heater and pump and remove the DEF tank from the car.

DEF tank heater element

Step 6

Remove all the 4mm hex bolts holding the pump to the DEF heater.

Step 7

The DEF pump must be removed from the DEF tank (top of the DEF heater). Remove the DEF heater element's big locking ring.

Step 8

The DEF heating element should be removed from the tank.

Move your hands into the tank and slide the plastic counter-clockwise to detach the inner heater portion from the tank.

The DEF tank of a Mercedes has been removed.

How to locate DEF tank

Step 9

Place the DEF pump and heater element in place.

Your new DEF pump will almost certainly include several O rings. Replace them all, including the one that links the heater element to the pump.

Step 10

Tighten the locking ring on the lid. Make sure the ring line up on the tank mark matches the ring line up on the ring.

Heater element connection to DEF tank

Step 11

The DEF tank should be installed on the vehicle. Add DEF fluid to the tank's top.

Step 12

Finally, clear the check engine light with an OBD2 scanner. If the problem is no longer present, you can drive the vehicle and the CEL will clear on its own. Our advice is to clear the code with a Mercedes Star Diagnostic scanner and then keep an eye on the CEL to make sure it doesn't come back.

NOTE: If you have a fault code connected to the DEF heater on your Mercedes BlueTec check engine light, you should have it fixed as soon as possible. Otherwise, ignoring the CEL may cause your Mercedes to enter limp mode, as well as a warning display on the dashboard indicating "x starts remaining," after which you will be unable to start the car, van, or SUV.

Heater element attatchment

If you're encountering issues with your DEF system, particularly the heating element, we recommend contacting a Mercedes-Benz dealer near you to see if there are any open recalls. Your dealer will fix the fault under warranty if there is an open recall. All emissions concerns are covered by a federally mandated warranty up to 80,000 miles.

You may have been told that you need to replace the DEF tank, heater, and pump all at once, which can cost up to $4000 at the dealer. Unless the DEF tank has developed a fracture, it is rarely required to replace it.

Faulty heater element

6. Conclusion

When a failure is initially detected in the Diesel System, it's critical to determine where the fault is originating from so that we can pinpoint the exact issue. Exhaust, DPF, AdBlue Tank, Heating Elements, and other components can all cause problems.

This is accomplished by reading the vehicle's fault codes, confirming the location of the problem, and tracing difficulties with any associated issues. Once we've done that, we'll present you with the most cost-effective pricing and payment alternatives.

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