Exhaust Gas Recirculation is an emissions control system that routes a metered portion of exhaust gases back into the engine's intake tract. Because exhaust gas is inert and displaces combustible oxygen, it lowers peak combustion temperatures, which prevents the formation of harmful nitrogen oxides.
Heard on the job
The customer has a rough idle and a check engine light, probably a carbon-clogged EGR valve sticking open.
Also heard as
- exhaust gas recirculation
Related terms
PCV
This emissions control system routes blow-by gases from the crankcase back into the intake manifold.
MIL
The dashboard warning light that indicates a fault detected by the engine control module.
Diesel particulate filter
An exhaust component that traps and periodically burns off soot from diesel emissions.