EGR System: Description

Purpose of the Exhaust Gas Recirculation (EGR) system is to limit formation of Oxides of Nitrogen (NOx) emissions. This is done by reducing peak combustion temperatures at which NOx is formed. By reintroducing some exhaust gas back into the combustion chamber, high combustion temperatures are avoided.

The system used on 2.5L and 4.0L engines consist of an EGR valve, vacuum transducer, EGR solenoid, and connecting hoses.

The system used on 4.2L engine consists of an EGR valve, Coolant Temperature Override (CTO) valve, Thermal Vacuum Switch (TVS), and connecting hoses.

The system used on 5.9L engine consists of an EGR valve, Coolant Temperature Override (CTO) valve, Thermal Vacuum Switch (TVS), forward delay valve, and connecting hoses.