Exhaust Gas Recirculation: Description and Operation

EGR System Components:

The EGR system returns a portion of the exhaust gas to the intake manifold to reduce the combustion temperature. This reduces the oxides of Nitrogen (NOx) in the exhaust emissions.

The PCM controls the EGR vacuum regulator solenoid. The EGR vacuum regulator solenoid controls the vacuum to the EGR valve. When the EGR valve opens, exhaust gas flows to the intake manifold. The differential pressure feedback EGR sensor measures the flow through the EGR valve to exhaust manifold tube and sends a signal to the PCM. A metering orifice in the EGR valve to exhaust manifold tube restricts the flow rate when the EGR valve is open.