How to Clean an Idle Air Control Valve

A man looks under the hood of a car.
What You'll Need
Socket set
Choke/carburetor cleaner
Cleaning rag

An understanding of your car's idle air control valve can prevent a rough ride and save you time and money. As automobile electronics became more sophisticated, a small motor called the idle air control valve or IAC appeared under the hood. The idle air control valve is a component that interacts between an automobile’s computer and the throttle body. It can be cleaned using these steps.

Step 1 - Finding the IAC

To correct an uneven idle or stalling engine, you may need to clean or replace the idle air control valve. It is a part of the electrical system on most modern cars and is located next to the throttle body. Trace the air cleaner hose across the top of the engine to where it connects to the engine. Remove the hose using a screwdriver or the proper socket to expose the throttle body. The idle air control valve will be adjacent to the throttle intake.

Step 2 - Removing the IAC

Before doing any work on the electronic system of an automobile, disconnect the battery cables. This should prevent any danger of shock or damage to components. The IAC valve is attached to the engine with four bolts or screws. A cone-shaped tip protruding from the valve is called the pintle, and it extends through an opening into the throttle body after the butterfly valve. As the pintle moves in and out of the IAC valve, it regulates the amount of air coming into the throttle body when throttle butterfly is closed, thereby increasing or decreasing the car’s idle speed. Movement of the valve is activated by the auto’s electronic computer. Three wires are connected to the component: one for current, one for a ground, and the other one leads to the computer. Remove the four retaining bolts or screws, as well as the wire assembly, and carefully pull the valve away from the engine. Mark the wires to assure proper reassembly.

Step 3 - Cleaning the Valve

Spray the unit with choke/carburetor cleaner and use a cleaning rag to remove all carbon buildup from the idle air control valve. Work the spindle back and forth to clean away all deposits found there. Also clean the throttle body while the butterfly valve is exposed.

Step 4 - Reassembling the Unit

After cleaning the IAC and throttle body, replace the valve to its original position on the engine. Make sure that the pintle fits again into the throttle’s airspace. Replace the bolts and screws and secure them tight. Reattach the wires to the proper terminals. Visually inspect the unit to ensure it is properly assembled and replace the air cleaner hose to the throttle body. Tighten all screws and bolts using a wrench, then reconnect the battery cables.

With a clean idle air control valve, your car should run smoothly. It is best if you test drive it before embarking on any long road trips.