Auxiliary Air Valve (Idle Speed): Description and Operation
IACV-AAC CONTROL SYSTEMOperation
When the air conditioner is OFF, the ECM detects the load applied to the engine, and controls the IACV-AAC valve to adjust the engine idling speed to the appropriate rpm by supplying additional air from the IACV-AAC valve.
When the air conditioner is ON (A/C relay is ON), refrigerant-pressure sensor converts refrigeration-pressure on the high pressure side into the voltage value, which is output to ECM which protects refrigeration cycle and control idle speed by the output voltage data, and additional air is supplied to the engine. If the appropriate engine speed is not reached, the IACV-AAC valve supplies the additional air required to increase the engine rpm.