Glossary / General

DEF

9 Episode Mentions

Too Afraid to Ask

DEF is a special liquid that you have to add to some diesel cars to help them pollute less. It helps clean up the exhaust gases so they are safer for the environment.

Technical Definition

DEF stands for Diesel Exhaust Fluid, a solution used in diesel engines to reduce harmful emissions. It is injected into the exhaust system and helps convert nitrogen oxides into harmless nitrogen and water vapor.

Hear It Discussed

"...you have to put this stuff called DEF and the all of the diesel cars that is essentially the Urea stuff you have to put in the off-subbiteration?"
983: The “New” Nissans, The One Dollar Car, The Wrong Song Everyday Driver Car Debate 11:42

"leaning something towards the def system ... unless it's been reprogrammed to compensate for that ... removed the def. Go into limp mode."
Under The Hood - LIVE Show Automotive Experts Giving You Advice Under The Hood show 34:19

"...if you don't know DEF, which is an additive that's used to clean up the exhaust system, it's an EPA mandated..."
#335 Trucking’s Underbelly Exposed: Illegal Labor, Fake Repairs, and Failing Oversight Wrench Nation 31:01