ACIS Control Circuit: Description
WARNING: This page is about a different car, the 2009 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.
When the Intake Air Control Valve (IACV) opens and closes, the ACIS control circuit causes the engine load intake efficiency to increase. When the engine is running at 2450 to 4100 RPM and the throttle valve opening angle is 30° or more, current flows through the ACIS control circuit and the IACV closes. For all other situations, current does not flow through the ECM and the IACV is open.