When the engine is running but the vehicle is not moving, it means that the engine is idling. During this period, the revolutions per minute (RPM) in the engine will change.

The idle air control valve is responsible for managing the idle speed of the engine. The valve is the main management component of the engine, it will reduce or increase the number of revolutions per minute according to the current operating conditions.

The valve is connected to the throttle body near the intake manifold. The engine control unit is responsible for managing the function of the valve. Based on the information it receives, such as engine load and temperature, it will change the idle speed accordingly.

How an Idle Air Control Valve Works

Engine speed refers to the number of revolutions per minute. This is commonly referred to as RPM. The current operating conditions of your vehicle will cause the idle air control valve to increase or decrease the engine RPM.

For example, if your vehicle is heavily loaded or heats up too fast, the idle air control valve will adjust the RPM by increasing or decreasing the RPM; respectively. This will allow the engine to handle heavier loads or cooling in every situation.

The engine control unit is responsible for managing the idle air control valve. When this central computer receives information about engine temperature and load, it will use this information to make appropriate adjustments to the idle air control valve.

In this way, the valve will correctly adjust the engine RPM based on the information transmitted by the computer.

Bad Idle Air Control Valve Symptoms

When your car's idle air control valve is damaged, some problems and symptoms will appear. If you do not replace the valve immediately, your car will not be able to drive.

The following are 5 major symptoms of a bad idle air control valve that you can easily notice.

1. Intermittent Idle Speed

Since the idle air control valve should manage the idle speed of the engine, a bad valve will definitely make it abnormal. It will cause the idle speed to randomly fluctuate to different speeds instead of maintaining a constant speed.

The idle speed may be too high at one moment and then too low at other moments. Just look at the tachometer on the dashboard and you will clearly notice this idling speed change.

2. Check Engine Warning Light

Whenever there is a minimal problem or problem with anything connected to the engine, it will cause the central computer to activate the check engine warning light on the dashboard. A bad idle air control valve may of course be a reason for this.

If the number of revolutions per minute seems to be unique to the engine control unit, it will notify you by activating the warning light.

Of course, there may be many reasons for the warning light to turn on. In any case, you should immediately take the vehicle to an auto repair shop for inspection.

3. Rough Idling

A normal idle air control valve will make your vehicle idle smoothly. But if the valve breaks for any reason, the idle speed will change from smooth to rough.

Whenever your vehicle stops with the engine running, a rough idle speed will cause strong vibrations. Since there is less air entering the engine when idling, the car will react through violent shaking.

4. Engine Stalling

If you stall the engine due to a malfunction of the idle air control valve, you will not be able to drive the vehicle at all. Once you start the car, the idle air control valve will fail immediately.

If you happen to be away from home and this happens, there will be a pause every few minutes at the beginning. You should be able to get to the nearest mechanic in time before the engine is completely shut down.

5. Load Causes Stalling

Sometimes the engine stalls will happen on their own, and sometimes, increasing the engine load will cause it to stall.

For example, if you turn on the heater or air conditioner when the idle air control valve fails, your engine may turn off immediately afterward. The steering wheel may also feel it has been dragged to the side.

To temporarily solve this problem, just turn off the heater or air conditioner to reduce the load. Then let the engine cool for a few minutes.

Idle Air Control Valve Replacement Cost

If the reading displayed by the voltmeter is out of the normal range, you need to purchase a new idle air control valve. Unless you know a lot about car maintenance, you need to pay a mechanic to perform the replacement work. This means you need to pay for parts and labor costs.

The average idle air control valve replacement cost is between US$120 and US$500. The cost of these parts may range from US$45 to more than US$400, while the labor cost is only about US$70.

Of course, labor costs really depend on the hourly wage of the mechanic. Since the execution time of this work should not exceed 1 hour, don't expect the cost to be too high.