EGR System - Diesel: Description

NOTE: California models with 6.2L diesel engines use an electronic EGR control system. See SELF-DIAGNOSTICS article.

Purpose of the Exhaust Gas Recirculation (EGR) system is to limit formation of oxides of nitrogen (NOx) emissions. This is done by reducing high peak combustion temperatures at which NOx is formed. By reintroducing a small amount of exhaust gas back into the combustion chamber, high temperatures are avoided and thus NOx emissions formation is reduced.

EGR system consists of, EGR valve, exhaust pressure regulator (EPR), EGR solenoid, EPR solenoid, throttle position switch (TPS) and vacuum pump.