Why RVers Should Know What a DEF Head

While the term DEF heads may sound like fans of some new music style, that’s not exactly what we’re talking about today.

Starting in 2010, they became an important component in many newer RVs and trucks. So why should RVers know what a DEF head is? Let’s find out.

A DEF head monitors the entire Diesel Exhaust Fluid system. It communicates to the essential components the quality and quantity of DEF in the system and that everything runs as it should.

It gives the engine control module the green light to start the engine. If a vehicle’s DEF head isn’t working, it will not run correctly.

What Is a DEF Head?

Passenger vehicles, big 18-wheelers, and motorhomes made after 2010 with diesel engines will have DEF tanks that drivers need to keep filled with diesel exhaust fluid.

What Types of Vehicles Have DEF Heads?

Sadly, DEF head failures have become increasingly common, especially since 2017. The EPA made a major adjustment to measure the concentration of the DEF.

Are DEF Head Failures Common?

While the DEF sensors initially seemed to fail for no reason, it was later determined it was a heat issue.

Why Are DEF Sensors Failing?

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