Description - EGR Air Flow Control Valve: Operation

The Exhaust Gas Recirculation (EGR) Air Flow Control Valve adjusts the flow of fresh air into the engine during EGR operation. A signal from the Powertrain Control Module (PCM) controls the operation of the EGR throttle valve. The position at which the PCM will set the valve depends on the blended quantity of exhaust gas that needs to be recirculated into the engine in order for the exhaust gas to remain within the target emission level, which the PCM calculates based on input received from the oxygen sensors. When not actuated, the EGR throttle valve is in the open position.