Intake Control System (Prelude)

Intake control system consists of an intake control diaphragm, an intake control solenoid valve, an intake control vacuum tank and an intake control check valve. When engine speed is less than 3970 RPM and engine air requirements are reduced, the PCM activates (grounds) the intake control solenoid valve. This supplies intake manifold vacuum to intake control diaphragm. Intake control diaphragm closes off one of 2 air intakes passages, to reduce intake air noise.