The Idle Air Control (IAC) valve is a component of the engine's air intake system. It regulates the amount of air entering the engine when the accelerator pedal is not being pressed.
Main functions:
Controls engine idle speed.
Maintains stable engine RPM when the vehicle is stationary.
Helps prevent the engine from stalling at idle.
Adjusts airflow when electrical or air-conditioning loads change.
Supports smooth engine operation.
Common signs of a faulty IAC valve:
Engine RPM goes up and down.
Engine stalls when idling.
Difficult cold starting.
Engine idles too high or too low.
Engine struggles when the air conditioner is switched on.
Check Engine light may come on.