Idle Up Control Valve: Description and Operation

On vehicles equipped with air conditioning, an additional air circuit is located in the throttle plate assembly and compensates for drop in idle speed when the compressor is operated. A solenoid valve, which receives an electrical signal from the compressor feed circuit, opens a vacuum circuit located behind the throttle plate. Vacuum is applied to a capsule which opens the additional air circuit at the throttle plate. On vehicles equipped with manual transmission, the maximum diameter of the additional air circuit orifice is .118 inch (3 mm), or .138 inch (3.5 mm) on vehicles with automatic transmission.