Idle Air System Operation
WARNING: This page is about a different car, the 2006 Suzuki Verona. However, it is still accessible from the selected car via links, so may be relevant.
The idle air system operation is controlled by the base idle setting of the throttle body and the Idle Air Control (IAC) valve. The Engine Control Module (ECM) uses the IAC valve to set the idle speed dependent on conditions. The ECM uses information from various inputs, such as coolant temperature, manifold vacuum, etc., for the effective control of the idle speed.