System Operation

When engine RPM is less than 5750 RPM, a signal from ECM energizes IAB control solenoid valve. Intake air is directed through smaller intake air path. When engine speed is more than 5750 RPM, IAB solenoid valve is deactivated by ECM.

When IAB solenoid is deactivated, vacuum is cut to IAB control diaphragm causing spring loaded IAB control valves inside intake manifold to open. When IAB control valves open, intake air goes through short intake path, reducing airflow resistance and increasing engine torque. A malfunction in IAB control system will cause a low engine power condition.