Circuit Description
WARNING: This page is about a different car, the 2003 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.
The rotary solenoid type IAC valve is located in front of the intake air chamber and intake air bypassing the throttle valve is directed to the IAC valve through a passage. In this way the intake air volume bypassing the throttle valve is regulated, controlling the engine speed. The ECM operates only the IAC valve to perform idle-up and provide feedback for the target idling speed.