Idle Up Control Valve: Description and Operation

The idle speed boost valve maintains the idle speed within a 300 rpm range, compensating for various engine loads (cooling fan, etc.) while at idle. A second valve is fitted on cars with air conditioning to boost the idle speed when the A/C is turned on. The electrically operated solenoid valves, located on the right strut tower, allow additional air to bypass the throttle plate and increase the idle speed whenever it drops below 750 rpm. Above 1050 rpm, the valves close and the idle speed is reduced.