Home Diagnosis and TroubleshootingProcesses, Mechanics, and Repairs What Does A Throttle Body Do – Everything You Need To Know!

What Does A Throttle Body Do – Everything You Need To Know!

by Jordan Harris
What Does A Throttle Body Do

Have you started noticing some weird symptoms on your car such as the check engine light and poor idle? 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 will learn what does a throttle body do and how you can diagnose and replace this component.

Having a problem with the throttle body is a frustrating thing to deal with. Why I’m saying this? Well, mainly because it is true, throttle bodies can be a real pain to get sorted out and in most cases, people end up replacing them altogether because cleaning them is close to impossible if the debris is too much accumulated on them.

This is why you need to learn first what does a throttle body do in order to understand the component and how it functions. Knowing how a component works is key in order to understand the symptoms that it will produce whenever it fails. And this is why we are going to help you out in the following chapters.

First, we will learn what is a throttle body and what does a throttle body do, then we will learn the diagram and we will elaborate more on the TPS sensor. After that, we will learn the bad throttle body symptoms and how you can diagnose and fix a bad throttle body easily. So, if you want to learn more about sorting this problem follow along.

What Is A Throttle Body?

Now before we dive into more complex topics and understand what does a throttle body do, let’s first learn what is this component in general. Knowing how this component looks and where it is located is key in learning where to find it in order to sort out this problem promptly, so let’s get into it.

As you probably know, cars in the past were using carburetors. The carburetor had flaps inside that opened and closed whenever you applied the throttle. Once the flap opened, fuel was sprayed into the barrels of the carburetor and this fuel was pushed into the cylinders.

But nowadays we live in modern times. So, the work of the carburetor was separated into two different components. One of these components is the injector that injects the fuel into the cylinder. And the other most important component for our article is the throttle body. The early throttle bodies were mechanical but modern ones are all electronic in other words drive-by-wire systems.

The throttle body is that flap that we mentioned that opens and closes. But where this component is located? The throttle body is located in front of the engine.

This component is mounted at the start of the intake manifold. And on one side is connected to the manifold itself, while the other side is connected to the intake hose that runs from the airbox.

The butterfly flap of the throttle body is not visible. So, in order for you to check this component and its condition, you will have to remove the intake hose and see the condition of this component. But what does a throttle body do? More on this we are going to cover next.

What Does A Throttle Body Do

Now let’s get to business and learn more about the throttle body and its function on the car. So, what does a throttle body do?

Well, the throttle body has a really important role in the internal combustion engine. Even though this is just a flap it regulates the airflow that enters the intake manifold. This throttle body reacts whenever you apply your foot on the throttle pedal and opens up depending on your input.

Allowing air to enter the combustion process. If this throttle body is not functioning as it should and the flap does not open correctly, you will have a ton of problems performance-wise.

The car will not be happy at all and you will face the bad throttle body symptoms. Something which is not ideal. We’ll elaborate more on the symptoms later on in this article.

Another thing to add is that this throttle body in most cars is drive by wire. Which means that it is electronically regulated.

Back in the early days when carburetors were the thing and also in the early days of throttle bodies, these components were regulated mechanically by a steel wire that moved once you pressed on the throttle.

The early throttle bodies also implement a component that is known as an idler air control valve. Which regulates the idle.

Nowadays everything is computerized and controlled by the ECM/PCM which is the car computer. But enough on what does a throttle body do. Let’s now cover another topic and that is what does a throttle body spacer do.

What Does A Throttle Body Spacer Do

Now as we learned what does a throttle body do, we can move on and talk about the throttle body spacers. What the spacers are and what is their main task?

This is sort of a mod that a ton of car guys are using. This mod basically allows you to have more airflow. This spacer increases the capacity of your intake manifold.

This spacer will give you more air into the combustion. Thus, better performance of the vehicle and increased horsepower. So, if you are one of those guys who want to do some mods, this is the mod you are looking for. It is really cheap and affordable in my opinion. It is definitely worth the cost to get a couple more horsepower.

Throttle Body Diagram

Now let’s discuss more on the diagram and learn the throttle body parts. From what parts are this component made?

Well, this component is fairly simple in design. There is a metal housing that houses everything and in the center, there is the butterfly flap that opens and closes.

On electronically controlled bodies, the flap is controlled by a special DC motor that is mounted on the body itself that helps open and close the flap.

There is also the TPS sensor that monitors the position of the flap. This is a really important sensor that we are going to explain in the following chapter.

What Does A TPS Sensor Do

We learned what does a throttle body do, now let’s learn what does a TPS sensor do. When it comes to throttle bodies, this sensor is probably one of your top priorities.

So, what is a TPS sensor? Well, this is a sensor that monitors the position of the butterfly flap of the component.

Without this sensor, your computer will never get the right data that it needs in order to determine the correct air to fuel ratio.

So, you understand why it is so important and this component should be one of your top priorities to check if the flap inside of the body is good and doesn’t have any debris on it.

Sometimes these TPS sensors fail and cause problems. What is worth noting is that this sensor has a small potentiometer inside. This potentiometer moves as you apply the throttle.

Then this sensor sends this data to the PCM and informs the PCM about the throttle body position. Whenever this sensor is working, it produces a voltage between 0 and 5v.

In most cases, this is a three-pin sensor. One wire is for the 5v supply, one wire is ground, and the last wire is the signal wire that returns the signal from the sensor to the PCM. And diagnosing these components is dead easy. You only need a multimeter. But more on this later on in the article. Now let’s learn more about the symptoms.

Bad Throttle Body Symptoms

Since we covered what does a throttle body do, let’s learn more about the symptoms that this component produces whenever it fails.

As we all know, every component when it fails it starts to produce symptoms. And so is the case with this component. So, what are the main symptoms of this component? Let’s elaborate on them thoroughly in the following chapters.

1. Check Engine Light

We learned what does a throttle body do, let’s now cover the first symptom that you will face when you are dealing with problems on this component. And that is the check engine light.

The check engine light is probably one of the most common symptoms that are associated with this component. But you can never know what this check engine light means unless you do proper diagnostics with a special tool also known as an OBD2 scanner.

What Does A Throttle Body Do

If this component or the TPS sensor is damaged you will get codes like P0300 that indicates random misfires. Codes concerning the actuator of the throttle body such as the P2119 or P0638.

Or codes that are associated with the TPS sensor, for example, P0121 or P0122. All these codes are associated with this component and need further investigation.

2. Rough Idle Or High RPM At Idle

Since we learned what does a throttle body do, let’s now cover the second most common symptom of a bad throttle body and that is the rough idle. Or high RPM at idle.

As you probably know when the engine is working at idle speeds, the RPM should be at about 800 when the engine is warmed up. If the idle is too high or too low, it could mean a problem with the TPS sensor potentiometer. Or possibly problems with dirt on the butterfly flap of the throttle body. Now let’s move to the next symptoms.

3. Rough Acceleration

Since we learned what does a throttle body do, now let’s cover the next symptom that is fairly common when this component fails. And that is the rough acceleration.

Whenever the butterfly flap of the throttle body is not working as it should, this component will result in producing symptoms such as rough acceleration.

What Does A Throttle Body Do

The car’s acceleration will not be smooth by any means. If you notice hesitation or jerking when accelerating, it could possibly mean that you have issues with this component. This is why you need to dive further into diagnosing and sorting out the matter. But more on that in a bit.

4. Engine Keeps Stalling

Now let’s cover another fairly common symptom that is associated with a bad throttle body and that is the situation with the engine stalling.

We learned what does a throttle body do and determined that this component is regulating the throttle response as well as the idle on more modern cars.

Modern cars do not use idler control valves as older vehicles do. So, if the body itself fails, meaning that the electric motor stops working. The throttle body will not be able to deliver the minimum air intake and the engine will stall immediately after start. The RPM will drop below 600 and the engine will shut off. So, beware of this symptom.

5. Poor Engine Performance

The next symptom that is associated with a bad throttle body that we are going to cover is the poor engine performance.

We learned what does a throttle body do and learned how crucial this component is when it comes to delivering enough air into the intake manifold.

What Does A Throttle Body Do

So, whenever this component fails, it will start to produce a ton of symptoms and the overall poor engine performance will be one of them. Whenever this component is bad, there will be a significant loss of power and this will be noticeable.

You will press on the throttle and nothing will happen or press on the throttle and nothing happens and suddenly the car lurches forward. A clear symptom is that something is going on with the fuel system or the throttle body.

6. Increased Fuel Consumption

And the last symptom that we would like to cover is the increased fuel consumption. The fuel consumption will increase quite significantly when this component fails.

We learned what does a throttle body do and learned that this component is crucial when it comes to the proper power delivery.

If the butterfly flap is open all the time, there will be too much air that will enter the combustion. The more air enters, the more fuel will be dumped into the combustion. And as we all know, more fuel burnt means increased fuel consumption and a really big gas bill. But how you can diagnose a bad body? Let’s learn more about that next.

How To Diagnose A Bad Throttle Body?

We learned what does a throttle body do and the symptoms associated with this component. Now it is time to move on and start diagnosing stuff. How we can diagnose this component?

Well, actually it is quite easy to do. The first thing you will need to do is to remove the intake hose and see the condition of the throttle body.

If it has a ton of carbon buildup around it, then it probably has some problems opening and closing. And you will definitely need to do some cleaning. If the debris is too much, you will have to replace the whole unit, unfortunately.

Also, you need to observe the flap and see if it opens and closes correctly. Tell someone to press on the throttle while the car engine is on and see how the flap works. If it doesn’t open or it opens slowly, it could be an issue with debris or the electric motor that is in charge of this component has failed and is not working.

It is also useful to grab an OBD2 scanner if you want to computer diagnose this problem. And frankly, this will be essential if you want to fix this problem.

There could be codes that are concerned with the actuator motor that opens and closes the throttle body. Or codes that are associated with the TPS sensor and also if you have an older car there could be codes concerning the idler air control valve. Then move on from there. Grab a multimeter and bench test the TPS sensor and the idler air control valve if you have one. And that’s how you address these issues.

Throttle Body Cleaner

Now let’s assume that your throttle body is clogged up with carbon deposits. How can you clean this component and make sure that there is no more carbon on it so it functions the way it should?

Well, for this purpose you can use carburetor cleaner. The carburetor cleaner is a solution that is designed to tackle these problems and clean carburetors, injectors, and throttle bodies. The throttle body cleaning cost if you do this work at home it will not cost you more than $10. Or if you do it at a shop you will pay about $100 for this service (if you don’t want to learn how to clean throttle body).

What you need to be aware of is that this fluid is highly flammable. Which means that it could burst into flames really fast.

So, remove the component from the car and give it a good cleaning. Scrub it really nice and make sure that you remove every piece of dirt on it.

If the dirt is too much and doesn’t want to come off, you might need to replace the throttle body. And that’s what we are going to discuss next.

Throttle Body Replacement

We learned what does a throttle body do, and how to diagnose and clean this component. But what if this component cannot be cleaned with a carb cleaner? What are the other options?

Well, the other options on the table include replacing this component. And in order to do this replacement, you need to find the right part for your car.

Not every component can fit your vehicle. This is why you need to search it by the part number. Also, the replacement is fairly straightforward. In the end, you might need to do a re-learning procedure in order so the new TPS sensor calibrates with the engine. So, if you don’t know how this is done, better leave this work to professionals.

Throttle Body Replacement Cost

Now let’s see what is the replacement cost, how much money can you expect to pay to replace this component on your vehicle?

Engine performance tuning specifications replacement cost diagnosis

Well, it is not that cheap. These components could easily cost between $200 and $600. The more exotic the car, the more expensive they become.

The labor on the other hand is quite cheap, it will not going to cost you more than $100 to replace it.

Throttle Body Cleaning Facts:

  1. Throttle body cleaning is necessary maintenance for a vehicle to run smoothly as it controls the engine’s air intake.
  2. Built-up grime and carbon deposits in the throttle body can affect vehicle performance and cause rough idling, sluggish acceleration, poor fuel economy, and stalling.
  3. Throttle body cleaning products are available in the market, such as Berryman’s B-12 Chemtool aerosol cleaner, CRC Throttle Body and Air-Intake Cleaner, WD-40 Specialist Cleaner, and Johnsen’s Throttle Body and Air Intake Cleaner.
  4. Throttle body cleaning products contain poisonous chemicals and are highly flammable and volatile, requiring safety measures when using the product.
  5. To use a throttle body cleaner, wear rubber gloves and eye protection, disconnect the ground terminal from the battery, remove enough air ducting to access the throttle body, apply the spray cleaner, use a small brush to loosen dirt and other deposits, remove the gunk with paper towels, place a small drop of general-purpose oil on the throttle shaft, clean the area around the throttle body and engine, reconnect the ducts, and reconnect the battery.
  6. Before attempting repairs, consult the owner’s manual or repair guide specific to the vehicle.
  7. If the air ducts cannot be removed, it is best to take the vehicle to a trained mechanic to handle the job.
  8. The level of change in performance after throttle body cleaning depends on how much residue was removed from the throttle body.
  9. Throttle body cleaning products are usable on all vehicles, but verify that the one selected is specifically designed for cleaning the throttle body and says so on the label or in the directions for use.
  10. Throttle body cleaning is a viable course of action to prevent problems due to a dirty throttle body and keep the vehicle operating at a higher level of performance.


In this article, we have covered quite a bit when it comes to the throttle body. First, we learned what this component is and what does throttle body do.

Then we covered the main symptoms associated with this problem and how you can diagnose and sort out the problem cheaply by cleaning the component.


Now let’s answer some frequently asked questions.

What Is A Throttle Body

This is a component that regulates the flow of air that enters the intake manifold. This is a component that has an electronic actuator and a butterfly flap that opens and closes whenever there is input by the driver. Meaning when the driver presses the gas pedal the flap opens and when depresses the pedal the flap closes.

What Does A Throttle Body Do On A Car

The throttle body regulates the flow of air that enters the intake manifold of the car. This component has a flap that opens and closes based on the input from the gas pedal. When the gas pedal is pressed, the air gets in, when it is depressed airflow is stopped.

What Does A Throttle Body Spacer Do

The spacer is an aftermarket component that is designed to increase the capacity of the intake manifold and deliver a bit more power. It is mounted between the body and the intake manifold. And is about an inch thick.

How To Clean Throttle Body

You can clean this component by removing it from the vehicle. Then get carburetor cleaner and spray the component really well. Then scrub until the carbon deposits are removed completely.

How To Clean Throttle Body Without Removing It

Unfortunately, you cannot effectively clean this component without removing it completely. The debris is really sticky and difficult to remove. So, removal of the component is essential if you want to successfully clean the debris out of it.

What Does A Throttle Position Sensor Do

The TPS sensor basically monitors the position of the flap. Then this sensor sends the data to the PCM and the PCM adjusts the air to fuel ratio based on this input.

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