What Is the Idle Air Control Valve?

An idle air control valve is contained within a vehicle's engine

Automotive engines are composed of many intricate parts. These parts must function with precision to ensure the engine functions properly. One crucial component in a car engine is the idle air control valve.

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.

References

• automedia.com: Sensor Troubleshooting: Idle Air Control Valve
• "Auto Upkeep: Basic Car Care, Maintenance, and Repair"; Michael E. Gray; Rolling Hills Publishing; 2007

Resources

• "How Cars Work"; Tom Newton; Black Apple Press; 1999