The idle air control valve sometimes known as an IAC, is an electrical actuating device designed to electromechanically control engine idle speed. The idle air control valve is an essential part of the vehicle engine management system, integrated into a bypass housing or located on or near the throttle body assembly. The idle air control valve allows a measured amount of air to bypass the throttle plate/butterfly when it is closed, enabling the ECU to accurately control the idle speed of the vehicle?s engine. The IAC position is adjusted quickly to compensate for engine load and is commonly required for or during engine start-up, cold start/engine warm up, additional electrical loads, deceleration, air conditioning and automatic transmission use. The IAC valve is controlled by an input signal from the ECU as required by the engine management system, the duration and frequency of the ECU input signal determines how long and how far the IAC valve opens, hence the amount of air that is allowed to bypass the throttle plate. The idle air control valve must be compatible with the vehicle engine management system; the Tridon idle air control valve range has been carefully researched and engineered to suit each specific application. As idle air control valve electrical circuits, technical specifications and appearance may vary; always refer to the Tridon vehicle application list to ensure correct part number selection.