The RCV(Recirculation valve) solenoid is pulse width modulated by the ECM to control the pneumatically actuated RCV. The RCV solenoid supplies or vents vacuum to the pneumatically controlled RCV to open or close the RCV.

The RCV(Recirculation valve) prevents back flow through the turbocharger when the throttle is rapidly closed to avoid undesirable noise. The high pressure downstream of the turbocharger is vented back to the intake air upstream when the RCV is open reducing pressure in the system.