Definition

• An idle air control valve is an electronic motor within the car engine, typically mounted on the throttle body.
  
  

Function

• Idle air control valves control idle RPM (revolutions per minute) speed via commands from the engine-control computer of the car. The idle air control valve adjusts the amount of air that bypasses the throttle plate of the fuel-injection system by opening and closing an air bypass passage inside the throttle body.
  
  

Process

• Idle air control valves contain a sense wire, which is used by the computer to determine the steps, or the current in or out position, of the valve. The computer detects the steps and compares them to the engine's current idle speed. The engine computer uses this information to determine how much to increase or decrease the idle speed.