The Mercedes Sprinter is the van of choice for many who need a reliable and roomy cargo van for business or pleasure. The name Mercedes says it all when it comes to quality, and owners swear by their investment in this vehicle. With any car, there can be issues that creep up every now and then, and the Sprinter is no exception.

One problem a diesel-powered Sprinter van may face is a faulty DEF heater. The DEF system has had issues not only in Mercedes but in other brands of diesel as well. This is understandable, as the technology has only been prevalent in the U.S. for a few years.

As with any new technology, reliability will increase over time. In this article, we will examine the symptoms and reasons for a malfunctioning DEF system heater and discuss what to do if you experience this problem.

The Function of the DEF

A Diesel Exhaust Fluid system or DEF system is standard on Mercedes Sprinter vans that run off diesel fuel. The purpose of the DEF system is to mix its contained fluid into your exhaust, which creates a chemical reaction. This turns harmful emissions into benign nitrogen and water. This system has been required in the U.S. since 2010 and has kept tons of harmful diesel exhaust from entering the environment.

The Purpose of a DEF Heater

Cold temperatures starting at 12 degrees Fahrenheit and below will cause the fluid to freeze and not be able to be sprayed into the exhaust. Each DEF unit has a heater installed to heat the fluid back to a liquid temperature to operate as designed and keep emission at a safe level.

Symptoms of a Faulty DEF Heater

A DEF system is required by law and has been designed in a particular way to notify you if your DEF system or heater malfunctions. The only symptoms you will see if your DEF heater is faulty is either it does not turn on and melt frozen fluid, or you get a notification by your Sprinter van.

A Mercedes Sprinter will only allow you so many starts before it will go into limp mode or shut down completely. When this warning indicator turns on, do not ignore it. Bring your Sprinter to a certified Mercedes diesel mechanic before your vehicle shuts down. A professional mechanic will be able to get you back on the road with a quick fix.

Caring For a DEF System

Your DEF system can be costly if it needs to be replaced. Here are some things to maintain to keep your system and heater running:

  • Use the proper concentration of fluid in your system.
  • Never store your extra fluid in anything that is not sealed to the elements. Any contamination is detrimental to your system.
  • Never store DEF in containers that ever held other fluids.
  • As with keeping your storage DEF free of debris, you need to make sure the fill area is clean before adding fluid. A small amount of contamination falling in can cause harm.
  • Never try and bypass your DEF heater or overall system. Not only can you ruin the unit entirely, it is illegal to try.

Replacing a Bad DEF Heater

A DEF heater or system failure will result in their respective replacements. As noted, these components are tied mandatory and will shut down your Sprinter van. Knowing the consequences of a malfunctioning DEF heater, we recommend you not take this on as a do it yourself project. If your vehicle is still under emissions warranty, the cost is not an issue, but if not and you take it to a dealership, you will find it a costly endeavor.

Escondido German Auto: Your DEF Heater Solution

At Escondido German Auto, we can have your Mercedes Sprinter up and running from any DEF system issues, Sprinter DEF Heater Failure Fix including a malfunctioning DEF heater.

We have served Escondido, Rancho Bernardo, and Valley Center, CA, and are the preferred German auto repair and service center in Escondido. We specialize in German vehicles such as Audi, BMW, Mercedes-Benz, MINI, Porsche, and Volkswagen.

We have over 20 years of experience in automotive repair and service. Our ASE-certified technicians will provide reliable service to you and your vehicle. Contact us today to bring in your car for servicing or repair.

* Mercedes-Benz Sprinter image credit goes to: DarthArt.

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