System Operation

When engine RPM is less than 5750 RPM, a signal from the ECM energizes the by-pass control solenoid valve to direct intake air through the long intake path. When engine speed is more than 5750 RPM, the by-pass solenoid valve is deactivated by the ECM. When solenoid deactivates, vacuum is cut to IAB control diaphragm causing spring loaded IAB control valves inside the intake manifold to open. When IAB control valves are open, intake air goes through both short and long intake paths.