How To Bypass Idle Air Control Valve

How To Bypass Idle Air Control Valve – All The Right Methods…

Are you having problems with the idle air control valve and you are looking for ways how to bypass idle air control valve? Well, if that is the case, then you are at the right place because there will be a lot to cover on this topic where we are going to learn how this work is done on the car.

Doing some modifications on your car like the idle air control valve bypassing sometimes can be necessary. Mainly because an idle air control valve stuck open or stuck closed can occur and you will struggle to run your vehicle.

So, a simple bypass should do the trick right? Or maybe not. Since every modification that you make can have an impact on the performance of the vehicle. You should keep this in mind and it is often advised that you replace the factory parts with other OEM components than modifying them or simply deleting them. But more on this, we are going to cover later on when we are going to learn about bypassing this component.

First, we will learn what is the idle air control system and what it does. Then we will cover the location of this valve as well as the diagram. We will also cover the bad IAC symptoms as well as the replacement and the costs involved. And lastly, we will cover how to bypass idle air control valve on your car. So, if you want to learn more about this topic, follow along.

Idle Air Control Valve

Now before we delve into learning how to bypass idle air control valve. Let’s take a look at what is an idle air control valve in general. I bet that there are a ton of folks reading this article that have similar issues such as this, and this is why we need to do some explaining first to introduce them to the topic.

So, what is an idle air control valve? Well, an IAC valve is something that was a thing back in the day but not anymore. Few modern vehicles have an IAC valve. All these old-fashioned devices were later replaced by electronic throttle bodies.

The IAC valve is simply a valve-like device that is installed on the throttle body that opens up at the engine startup to bypass the throttle body butterfly valve and allow air to enter the intake and that’s it.

Since the throttle body is fully closed at startup, an IAC valve is necessary to get air into the engine in cold weather conditions. Once the engine is nice and warm, the IAC valve will reduce the airflow in order for the engine to run at idle RPM.

Thus the name idle air control valve. So, you get the idea. Nowadays the electronic throttle bodies have greatly replaced these IAC valves on cars. Mainly because sometimes these IAC valves can fail and cause some problems that we are going to elaborate on later.

You can find these idle air control valves on vehicles that are from the 90s era or the early 00s. Later on, we are going to learn more about this where we will cover the location and then how to bypass idle air control valve.

Why Is The Idle Air Control Valve So Important

What is important for you to know before we dive into how to bypass idle air control valve is that this valve if not in good condition can create problems running the engine.

And there could be some serious issues, trust me. Inside this valve, there is a spring that often can get clogged up with gunk.

So, when this happens, the IAC valve will not deliver a proper idle on your car and your car will basically struggle to run properly.

How To Bypass Idle Air Control Valve

But what is interesting to know about IAC valves is that they have a fuse in the fusebox. The fuse works as a safety switch. So, what a lot of people don’t know is that the fuse can die.

So, instead of replacing the IAC valve outright from the get-go, check the fusebox first and see if there is some fuse that is blown. If there is, then just replace it.

Some people though are really annoyed by these valves and they are looking for ways how to bypass idle air control valve. And if you are one of those, I completely understand you. But you should try some tricks first before you decide that you want to completely bypass the IAC.

So, first, we will focus on solving the problem and then on how to bypass idle air control valve. Now let’s dive into the location of this valve and learn more about it.

Idle Control Valve Location

Now before we dive into how to bypass idle air control valve, let’s discuss the location of this valve. Why is this necessary?

Well, now all people are experienced and have the know-how to find this component. So, we decided to help you out find it and make sure that you locate it correctly. And the location greatly depends on the engine layout.

For example, if the car has a rear-wheel-drive layout, the front of the engine is always in front of you when you open the hood.

The next thing you will need is to locate the airbox that contains the air filter. And then follow the air filter hose that goes to the intake. And right before the intake starts, the throttle body and the IAC valve should be located.

The IAC valve is usually mounted on the top of the throttle body. But in some applications, it can be mounted on the side. On the rear, it has an electric plug that goes to the wiring harness. While on the other side is mounted on the throttle body with two bolts.

On front-wheel-drive cars, on the other hand, the layout can be different. And in this case, the intake is always on the left side of the engine when you open the hood. And this means that the throttle body is placed diagonally.

Same story here. Just track the air filter and follow this hose till the intake. Right before the intake, the throttle body should be located and on top of the throttle body, the IAC valve should be mounted. But how to bypass idle air control valve? More on that we will cover in a bit.

Idle Air Control Valve Diagram

Another topic that we would like to cover before we start discussing more about how to bypass idle air control valve is the idle air control valve diagram. Let’s cover more on the diagram of this system.

As you are probably aware, the IAC control valve is mounted on the side or on the top of the throttle body.

This valve is held by two screws on the inside and on the other side there is a plug that is connected to the wiring harness and the ECU. So, the computer is able to constantly monitor the work of the IAC valve and tell it when to open and close.

Inside the valve, there is a small piston and a spring that moves in and out based on the input from the computer. So, if the computer says, hey I need more air into the engine, then, in this case, the IAC valve will open and allow more air to enter.

Then when the computer says, hey, enough air, for now. The IAC valve will close and there will be no more air passing through the valve. Simple as that.

You can also check online for more information on how this IAC valve works. But overall, this is the main principle of work. Now before we dive into how to bypass idle air control valve, let’s cover some of the symptoms that this valve produces.

Idle Air Control Valve Symptoms

Now before we start digging deeper into the IAC control valve and how to bypass idle air control valve. Let’s first take a look at the symptoms of this component.

As you are probably aware, each component when it fails it starts to develop symptoms. And so is the case with the idle air control valve. This is why we think that covering all these symptoms is really essential for people who are not familiar with them.

Knowing the symptoms will really help you out when it comes to diagnosing the problem and making sure that the problem is caused by the IAC valve. So, let’s cover them briefly.

1. Check Engine Light

Let’s cover the first symptom before we start discussing more on how to bypass idle air control valve. And the first symptom is the check engine light.

As you probably know, this component is connected with the ECU. So, it gets input from the ECU about when to activate.

And when the IAC valve has failed and the solenoid internal circuit has shorted out or possibly the IAC valve has been blocked, it will trigger a check engine light and a code.

How To Bypass Idle Air Control Valve

The most common code concerning the IAC valve is the P0505 code. This code definition is “Idle Control System Malfunction”.

Basically, the code is trying to tell you that your IAC valve has malfunctioned and needs to be checked. Because of symptoms like this, it is often advised to have an OBD2 scanner.

You will be able to tell that the IAC valve is bad in a few minutes. This is why we encourage you to get one of these tools. Now let’s continue with the symptoms.

2. High Engine Idle

Now let’s dive into the second most common symptom before we dive into how to bypass idle air control valve and this is the high engine idle.

Having bad idle is understandable when you are having an issue like this with the IAC valve. If the IAC valve is stuck in an open position. It will drive too much air into the intake.

And more air than necessary can only mean one thing, and that is abnormally high idle. Remember that the idle needs to be just a tiny bit open when the engine starts at cold temperatures. That’s the whole purpose of this device.

But if the valve is constantly open, it means that you will constantly have this situation. And the engine RPM will be constantly high at 1,000 RPM or something similar. Which is not a good thing.

This means that the engine needs to have proper airflow. More air will do nothing good to the air-to-fuel mixture. But more on this we will cover in a bit. Now let’s move on to the next symptom.

3. Low Engine Idle

The next symptom that we are going to cover before we dive into how to bypass idle air control valve is the low engine valve. So, why is this the case? Why the engine idle is low?

Well, if the valve of the IAC unit is closed and does not like to open. Your engine will struggle to run when you do a cold start. The engine RPM will be the same in this case as when the engine is warmed up.

So, a cold engine with a low amount of fuel and a lean air-to-fuel mixture will not do anything good to the work of the engine. So, if the RPM is low when you start the engine and the engine is cold. It could mean that there is a problem with the IAC valve.

Now let’s move on to the next symptom in our list of symptoms of a bad IAC valve before we start discussing more about how to bypass idle air control valve.

4. Engine Stalls

The next symptom that we are going to cover before we learn more about how to bypass idle air control valve is the situation when the engine stalls. So, why is this the case? Why your engine is stalling on you?

Well, the engine will be stalling as we said, the IAC valve will not like to open, and in cold temperatures, starting the engine will be a complete nightmare.

The air-to-fuel mixture will be always lean and not enough to sustain combustion at these temperatures.

So, the engine could continue running. But most likely it will stall on you a few seconds after you start it. This is a clear indication of a bad IAC valve. Unless you have some other problem with the ignition and the battery. Now let’s move on to the next symptom before we discuss how to diagnose a bad valve and also how to bypass idle air control valve.

5. Rich Air To Fuel Mixture

And the last symptom that we are going to cover before we dive into how to bypass idle air control valve is the rich air to fuel mixture. So, what is a rich air-to-fuel mixture?

A rich air-to-fuel mixture is a condition when the car is running more on fuel than on air. So, at the startup of the engine, every car is running rich.

And if the IAC valve does not close, your car air to fuel mixture will still be rich and this could lead to a situation when you have backfires in the exhaust. Exhaust backfire is a situation when the gasoline ignites inside of the exhaust and creates strong audible bangs.

You could also smell the unburnt gasoline, as well as black smoke coming from the exhaust, and this is not ideal. In this case, you need to learn how to diagnose the idle air control valve. And that’s what we are going to discuss next.

Diagnosing A Bad Idle Air Control Valve

Now before we dive into the topic of how to bypass idle air control valve. Let’s take a look at how you can diagnose one.

So, the first thing you would want to do is to grab an OBD2 scanner and plug it into the car. A code that indicates a problem with the IAC valve is often the P0505 code or something similar. On pre-OBD2 vehicles, code 11 indicates a problem with this valve.

So, if you have a code, then you are on a good track. In this case, you want to do is to grab a multimeter and test the idle air control valve with a multimeter.

You can test the harness first and see if you get power if the signal is good and also if the ground connection is all right.

Then you would want to test the IAC control valve. More specifically to test for resistance. Usually, a good IAC valve should deliver 30 Ohms.

And the last test you can do is to remove the IAC valve and leave it plugged in the harness. Then turn the key on the ignition and monitor if the valve opens when the engine starts. This is a really straightforward test that anyone can do with a second person.

More on all these methods and how they are done, you can check in the video above. Now let’s take a look at how to bypass idle air control valve.

How To Bypass Idle Air Control Valve

So, we learned how you can diagnose a bad IAC valve. Now let’s take a look at how to bypass idle air control valve. In other words how to do an IAC valve delete.

You can do this task with a block-off plate. For this purpose, you will need to fabricate a plate to cover the place where the IAC valve is mounted on the throttle body itself.

So, you need to step up your game and improve your fabricating skills. Then block off the IAC valve and you will be good to go.

Still, you might face some running issues if you do this and we would not recommend this practice if you live in a relatively cold environment because the engine could run quite poorly.

Not to mention that if you delete the IAC valve, you will be constantly greeted with the check engine light. So, take these things into consideration before you learn how to bypass idle air control valve. How the procedure is done, can check in the video above.

Idle Air Control Valve Replacement Cost

When it comes to the idle air control valve replacement cost, we can say that this part is on the more expensive side.

How To Bypass Idle Air Control Valve

On average the part cost about $100 to $200. But in some instances, these parts can be even more expensive. Mainly because they are not easy to come by since many carmakers ditched this design a long time ago. The labor will also cost you $100 to $150 to replace it.

Conclusion

In this article, we have covered quite a bit when it comes to the topic of idle air control valve. First, we learned what this valve does and how it works, its mounting location, and a basic diagram.

Then we covered the main symptoms and how you can diagnose this component. Lastly, we learned how to bypass idle air control valve.

F.A.Q

Now let’s answer some frequently asked questions.

What Is IAC Valve

The idle air control valve is a special valve that is mounted on top of the throttle body. This valve engages when you put the key in the ignition and allows more air to enter the intake by bypassing the throttle body butterfly flap.

Where Is The Idle Air Control Valve Located

The IAC valve is located on top of the throttle body or on the side of the throttle body. It is relatively easy to find. It has a wire connector on it that goes to the wiring harness.

Can A Bad Idle Air Control Valve Cause Hard Starting

Yes, it definitely can, especially in extremely cold temperatures. And that is the whole purpose of the idle air control valve to enrich the air to fuel mixture so the car starts quicker and warms up better.

How Do I Reset My Idle Air Control Valve

You cannot reset the valve if it’s not working. The only way around is to replace it. If you want the check engine light to disappear, you can delete the codes with an OBD2 device, or try to remove the positive terminal from the battery and then plug it back in.

How To Test Idle Air Control Valve

You can do a simple test. Just remove the IAC from the car and turn the key on the ignition. In this case, the valve should activate. If it doesn’t activate, then the IAC valve is bad. You can also test the resistance of the IAC valve. Good reading should be 30 ohms on all of the pins.

Approved Tools

These tools have been tried and tested by our team, they are ideal for fixing your car at home.

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