Glossary

DPF – Diesel Particulate Filter

This is the First Filter in the exhaust system that catches the carbon being produced from the engine.

SCR – Selective Catalytic Reduction

This is the part of the exhaust that mixes the NH3 (Ammonia or DEF) with the NOx (Nitrous Oxide) coming from the engine to produce H2O (Water) and Nitrogen.

DEF – Diesel Exhaust Fluid

A fluid which is introduced into the exhaust system through a dosing valve. This occurs after the diesel particulate filter and just before the selective catalytic reducer.

EGR – Exhaust Gas Recirculation

This is a mini tailpipe installed to trap a small amount of exhaust coming from the engine. It sends this dirty exhaust back into the engine to mix with a clean air/fuel mixture to be re-ignited by the pistons.

NOx – Nitrous Oxide

A gas which is created when the exhaust system is not working efficiently.

Re-gen –Engine Regenerating

This is when the engine idles up to create a hotter than normal exhaust, causing the diesel particulate matter (soot) to burn off.

Limp Mode

This is when the truck computer goes into a protection mode and begins shutting the truck down in order to protect the engine. Once the truck is in limp mode, a technician is required to clear the computer codes and put the truck back into regular use.