Theory Of Operation
The Exhaust Gas Recirculation (EGR) Airflow Control Valve is controlled by the Powertrain Control Module (PCM) and is actuated by an electric motor. A spring internal to the actuator assembly attempts to drive the valve to the fully-open position. The electric motor works to overcome the spring force when the PCM commands the valve to close. Position feedback from the valve is sent to the PCM to allow for closed-loop control. Discrepancy in position feedback sent to the PCM, and commanded position sent to the EGR Airflow Control Valve by more than a prescribed amount will result in failure of device rationality diagnostics. Failure to properly actuate the EGR Airflow Control Valve can result in poor engine performance. This may cause active Exhaust Aftertreatment regenerations to last longer.