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Idle Air Control Valve Symptoms – Keep An Eye Out For The Check Engine Light! 

Idle Air Control Valve Symptoms

What is the idle air control valve?

The idle air control valve is connected to the throttle body of your intake manifold. The engine control unit is in charge of monitoring all of the valve’s functions within your vehicle. 

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  • The intake manifold ensures that air is evenly distributed to all of the cylinders within your vehicle. The air is then used during the first stroke of the engine combustion process, helping cool down the cylinders to prevent the engine from overheating. 
  • The throttle body is located between the air intake and engine manifold, helping distribute the fresh air into the combustion process engine.
  • The engine control unit is a type of unit that controls a series of actuators that control the timing and the rate of internal combustion within the engine. 

What is the purpose of the idle air control valve?

The idle air control valve aims to monitor and regulate the idle speed, increasing and lowering the speed to keep up with the engine’s demands by the driver and road conditions.


To analyze and recognize the faulty idle air control valve symptoms, drives need to know the purpose of this part within their vehicle. This engine management component is found in almost all cars that are on the road today. 


Most idle air control valves are motorized valves or motor located on the vehicle’s intake manifold. The engine control module controls the valve or motor, adjusting the idle speed according to the temperature within the car and the system load. 

Most Common Idle Air Control Valve Problems

There are two most common issues that can cause faulty idle air control valve symptoms in cars today.

Clogged Idle Air Control Valve

Due to the amount of air flowing in and out of the idle air control valve, contaminants, dirt, and debris can enter the valve chamber during this exchange. These particles or contaminants could result in a clogged valve, jammed system, or damage to the internal parts. 

Failing Idle Air Control Valve

The second most common problem when addressing the idle air control valve symptoms is the valve no longer receiving an electrical signal or seals wearing down, resulting in the valve completely failing and preventing the car from starting. 

Faulty idle air control valve symptoms

When you notice the idle air control valve symptoms, this typically requires some type of repairs or replacement to keep your car operating at a smooth level. If the valve fails, it can cause all types of issues with the car, sometimes rendering it useless for the future. Usually, you will notice the idle air control valve symptoms almost as soon as they start occurring. 

  • Irregular Idle Speed

One of the most noticeable and frequent symptoms associated with the idle air control valve symptoms is irregular idle speed. The idle air control valve is designed to maintain the idle speed consistently throughout the entire time you drive your car. 


If the valve fails or has issues, it can cause the engine idle speed to be altered without meaning to. This change in the idle speed can result in an unusually high or low engine idle, causing a surge that results in a decline in engine performance. 


An irregular idle speed may be too high at one moment and then suddenly drop too low at other moments. Drivers will notice this idle speed altering by looking at the tachometer on the dashboard. 

  • Check Engine Light

One of the most noticeable idle air control valve symptoms is the check engine light flashing on the dashboard or appearing for a long period of time. If the engine control module notices an issue with the idle air control valve or signal, it can turn on the check engine light to alert the driver to any performance issue. 


Various issues can also set off the check engine light, so you should use a diagnostic tool to scan for trouble codes that could be stored in the engine. 

  • Engine Stalling

One of the more serious idle air control valve symptoms is engine stalling. If you find this occurs, it can sometimes lead to high crash risk, since your car would stall while driving at high speeds. If the idle valve control fails completely, it can leave the vehicle without any power source. 


Without any power source to the engine, it can result in the engine stalling or having a rough idle. 

What happens when your engine stalls?

  • If the car engine stalls while driving, your power steering will be the first thing you notice because it will not be working anymore. Power steering system helps the drivers steer the vehicle by changing the steering effort needed to turn the steering wheel, making it easier for the vehicle to turn or maneuver in specific conditions. 
  • When the power steering dies in your car, the wheels can still move, but it will be much harder to turn. In addition, the power brakes and the pedal may no longer be responsive and slow down your car, making it hard to control the car. 
  • Depending on when your car stalls while driving, this can affect what precautions you should take. If the car stalls while driving when you are at a red light, put on your hazard lights and slowly maneuver your car to the side of the road. If you can’t move your car, then you will need to dial for help and have someone help push your car to the side of the road. 
  • Rough Idling

One of the next most common idle air control valve symptoms is your car having a rough idle. A healthy idle will not cause any vibrations or bumps, but a rough idle will cause intense vibrations from the origin of the problem to the passengers and drivers. With less air going into the engine, the car reacts by profusely shaking. 

  • You can tell your vehicle is having a rough idle if there are shaking and bouncing sensation in the vehicle, and you feel like the car is vibrating too much while your car is not moving. Although some cases are less severe than others, the rough idle is usually pretty identifiable by both the driver and passengers.
  • You might also notice strange sounds when the car has a rough idle in addition to the vibrations. Along with the strange sounds, there might be an inconsistent engine RPM. Typically, a healthy vehicle will have a smooth RPM that stays at a consistent level of around 1,000 revolutions. If your vehicle is going too far below this line or moving too far above, then you might be dealing with a rough idling issue. 
  • Stalling Under Heavy Loads

Sometimes the engine stalling can happen on its own – however, it can only happen when the engine is under increased loads, whether it is towing heavy weights or going uphill constantly. For example, if you turn on your heater or air conditioner to the highest setting, your engine could potentially stall due to the idle air control valve symptoms. 

Steps to Fixing the Idle Air Control Valve Symptoms 

To fix the idle air control valve symptoms that cause engine stalling, rough idle, the check engine light, and irregular idle speed, drivers may need to clean the idle air control valve once they notice issues. One common problem that can cause the signs of a faulty idle air control valve is the carbon buildup of deposits in the valve. 


The best method to fix the idle air control valve is to clean the mechanism by following these instructions.

  1. First, you need to locate the idle air control valve. Fortunately for new car DIY owners, this step is easier than you may think. The idle air control valve is located between the throttle body and the intake manifold. 
  2. Next, disconnect the car battery to turn off the electrical components in the area where you will be working. Failing to do so can result in you being electrocuted or harming other electrical parts, increasing the overall replacement cost. 
  3. Once the battery is off, access the idle air control valve by removing any other parts restricting your access. 
  4. Disconnect the air intake ductwork from the throttle body. As we know, the throttle body is located between the air intake and the manifold. 
  5. Disconnect the electrical sensor on the backside of the idle air control valve. You can usually remove these connectors by hand, but sometimes you may require a tool if they get stuck or jammed in the palace. 
  6. Start your car's engine. Slowly increase and hold the idle speed consistently at between 1,000 and 1,500 RPM on the tachometer.
  7. Spray the throttle body cleaner or the engine cleaner into the main compartment of the throttle body. If you have not done this before, locate the idle air bypass port and spray most of the cleaner into this area. 
  8. Turn the engine off to let the cleaner soak into the passageway without getting too hot. 
  9. Wait between 3-5 minutes for the cleaner to take effect.
  10. Restart your car’s engine. Rev the engine and hold the RPMs at between 1,000 and 1,500. 
  11. Now repeat the entire cleaning process (steps 1-6 in order).
  12. Turn the engine off and reattach the air intake duct to the throttle body. 
  13. Start your car’s engine and increase the idle speed to between 1,500 and 2,000 RPM. During this step, drivers have to take note of any white smoke coming from the exhaust pipe. Continue revving the car until there is no more white smoke emitting from the car.
  14. Lastly, if the idle speed continues to surge, this is one of the most common idle air control able symptoms. In this case, you need to replace this part before driving your car. 

Idle Air Control Valve Replacement Cost

If you find the idle air control valve symptoms are too severe to fix on your own, you may need to replace this part before it causes any further damage. If a voltmeter shows a too high or too low reading, you need to purchase a new part. We recommend bringing your vehicle to a local mechanic or professional to do the replacement job. 


The average replacement price for the idle control valve is between $120 and $500. The cost of the parts is between $45 and $400, while the labor is around $70 for between 45 minutes and 1 hour of work at most shops. 

Can you drive with a faulty idle air control valve?

Sometimes you can drive with a broken idle air control valve, but this depends on the specific situation and type of car. Other times, driving with a faulty idle air control valve can lead to further idle air control valve symptoms, resulting in increased engine damage and reduced performance. Due to this risk, drivers shouldn't drive with a faulty control valve.


Although drivers may think they can avoid this problem by preventing idling in their car, every time you stop at a stop sign, roundabout, red light, or another road stop can cause your vehicle to idle. In this case, you will experience idle air control valve symptoms. 

The Bottom Line

There is nothing worse than seeing the check engine light appear on your dashboard when you feel like your car has been running at a high level. It kind of feels like nothing can go right in your car, and it results in you stressing about the durability, longevity, and performance of your vehicle. 


Fortunately, the idle air control valve is quite a cheap replacement and repair cost compared to other engine components. If you do this job yourself, you can remedy the idle air control valve symptoms and keep the repair costs at an all-time low by skipping the high labor prices. 


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