Exhaust Gas Recirculation: Description and Operation

Exhaust Gas Recirculation (EGR) System
Refer to the System Diagram to see the functional layout of the system.

Exhaust Gas Recirculation (EGR) System Diagram




The EGR system reduces oxides of nitrogen (NOx) emissions by recirculating exhaust gas through the EGR valve and the intake manifold into the combustion chambers. The ECM/PCM memory includes the ideal EGR valve lift for varying operating conditions.

The EGR valve position sensor detects the amount of EGR valve lift and sends it to the ECM/PCM. The ECM/PCM then compares it with the ideal lift in its memory (based on signals sent from other sensors). If there is any difference between the two, the ECM/PCM controls current to the EGR valve.

EGR Valve

The EGR valve is designed to lower peak combustion temperatures and reduce oxides of nitrogen emissions (NOx) by recirculating exhaust gas through the intake manifold and into the combustion chambers.