Idle Air Control Valve
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2002 Mazda Tribute, 2002 Mazda Protege5, 2002 Mazda Protege, 2002 Mazda Millenia, and 2002 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.
Idle Air Control (IAC) valve is an electromechanical device controlled by the PCM. The IAC valve is mounted on the throttle body and allows air to by-pass the throttle plate. The amount of air allowed to by-pass the throttle plate is determined by the PCM and is controlled by a duty signal.
During cold engine operation, the IAC valve opens, raising idle speed to a predetermined RPM. The IAC valve also compensates for all engine loads during warm engine operation to maintain a preset idle RPM.