4 Runner 4WD V6-180.5 2959cc 3.0L SOHC (3VZ-E) (1989)
Idle Up Control Valve: Description and Operation
Whenever the ECU senses activation of the air conditioning compressor, the Idle-up VSV is activated to increase base idle speed. The Idle-up VSV is
a calibrated air bleed around the throttle valve and feeds air to the engine through vacuum hoses. The Idle-up VSV inputs the ECU through terminal
ACV.