What Electronic Throttle Control Light Means And How To Fix It

All modern vehicles nowadays have electronic throttle control units. This means that your gas pedal is not mechanically attached to the throttle.

It is all electronically controlled and if something happens with your throttle control unit(ETC), it will most likely drop a warning light on your dashboard.

But you are probably wondering:

• What does it mean?
• How to fix it?
• Is it possible to drive?

Today, I will answer all these questions and give you enough information to prepare if your ETC system goes bad.

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Often times the electronic throttle control warning light is underestimated and can lead to much bigger problems than you can expect.

So keep reading!

What Does Electronic Throttle Control Light Mean?

As you already know, your car is a network of a lot of different components, which serve different purposes. That’s especially true when speaking about the throttle system.

In the past, vehicles used to operate with a mechanical throttle which means that the harder you press the pedal the more acceleration you’ve got. To be honest, the principle of acceleration stays the same these days, but how it operates has completely changed.

How Does The Electronic Throttle Control System Works In Modern Vehicles?

Nowadays, the ETC system is used to electronically connect the accelerator pedal to the throttle body, which completely replaces the need for a mechanical linkage. 

The electronic throttle control’s main purpose is to regulate the flow of air and fuel that goes into the combustion chamber. This is a device that’s built into your accelerator pedal and helps to reduce any potential power loss caused by air resistance, especially at higher speeds.

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Simply put, the throttle position is measured by a sensor that regulates how much power goes to your vehicle.

Oftentimes, the first question that comes to your mind is “Doesn’t this limit the power of my vehicle?”. Yes and no. Manufacturers are doing this for a variety of reasons:

• Increased Fuel Efficiency: The ETC system can optimize the throttle response based on driving conditions and drive style which leads to better fuel economy.
• Reduced Emissions: Manufacturers use the ETC system as a part of their emission optimization. The precision that you get with an electronic throttle unit is a lot better compared to a standard mechanical linkage. This means that you are using exactly the amount of gas needed to keep your vehicle running at different RPMs.
• Improved Safety: In some situations, the ETC is designed to limit the throttle opening to prevent unintentional acceleration. This is often integrated with the ADAS systems like adaptive cruise control and lane-keeping assist.
• Elimination of Mechanical Linkages: Traditional throttle systems rely on mechanical linkages (like cables) between the accelerator pedal and the throttle. These can wear out over time and require maintenance. This doesn’t mean that you won’t have issues with the throttle but certainly reduces the maintenance cost by a lot.

Fun Fact – The so-called “Remap” of a vehicle is based on changing the values in the “Maps” in your ECU like the amount of air and fuel that goes to your engine, how much PSI your turbo is operating at and etc. Usually, there’s also a “Map” about the ETC where you can change the responsiveness of the throttle making the car a lot more responsive when you press the accelerator pedal.

Why Do You Need An Electronic Throttle Unit?

If you look at it from the maintenance aspect an electronic control unit is much more cost-efficient compared to all the mechanical parts that were needed in the past. In the days we live in today we’ve completely forgotten that in the past people used to maintain their throttle system because it used to wear out.

Another thing worth mentioning is the fact that the ETC system is far more precise and accurate. 

For example in the past, the heavier load you put in your car, the harder you need to press the pedal. Imagine that on a long road where you constantly need to press the accelerator pedal, in the end, you are far more exhausted from the long trip. With the electronic control module, this is no longer an issue. It doesn’t matter how much load you put in your car, the pressure stays the same.

The third thing worth mentioning is the fact that the ETC like a lot of the technologies nowadays, is just more convenient. The integration of the ADAS systems like cruise control and lane keeping assist is integrated with the ETC unit which gives you the chance to control the throttle from the onboard computer.

What Happens If The Electronic Throttle Control Light Comes On?

Now that you know how the ETC unit works, let’s discuss what happens when the electronic throttle light comes on.

Usually, you will easily understand when you have an electronic throttle control problem because the warning light comes immediately on your dashboard.

But what this means? Well, you are going to have a hard time driving your vehicle.

Let’s discuss some of the issues that you will encounter when there’s a problem with the throttle unit.

Higher Fuel Consumption

As I mentioned above, the ETC unit is designed to operate efficiently. This means that it sends the exact amount of fuel and air into your engine based on the current driving conditions and the input it receives from other sensors in the vehicle.

This on the other hand helps the vehicle to operate efficiently and therefore reduce fuel consumption. 

However, if there’s a problem with the throttle position sensor, this monitoring becomes impossible and your vehicle won’t operate the way it should, increasing the amount of fuel your engine gets therefore increasing fuel consumption.

Limp Mode

The so-called “Limp Mode” means that your engine is not operating at maximum performance, which can be caused by a variety of reasons and the ETC is certainly one of them. If there’s a problem with the throttle control the ECU may limit the vehicle’s speed and acceleration might feel sluggish or non-responsive.

As I said the Limp Mode can occur for a variety of reasons and oftentimes the ETC light won’t come on. So the only way to make sure that there’s a problem with the throttle control you will have to use a good OBD2 scanner to clear the codes and can access this module. 

Rough Idle

When any component in the ETC system goes bad, you can feel rough idling. This can be caused by a sensor or any other component that is related to the throttle control system.

Rough idle means that your engine may operate at either higher or lower RPMs. You can easily feel that when your car is not moving while the engine is running.

Check Engine Light

Along with the ETC light, the check engine light might also illuminate. This usually means the engine control module (ECU) has detected a problem that needs to be addressed.

This happens because your ECU is directly related to the throttle control unit and any sudden changes will impact the vehicle’s normal operational values and therefore cause a CEL.

Possible Causes That Can Trigger The ETC Light

Now that you know what you will notice when there’s a problem with the throttle control unit, let’s find out what can be the reason for this.

As I’ve mentioned above the ETC is made of a lot of different components. But where exactly is the issue?

Let’s find out.

Faulty Throttle Body

The throttle body controls the amount of air flowing into the engine. It’s a crucial component of every vehicle. Oftentimes this module gets faulty and can disrupt the amount of air-fuel mixture that goes into the engine and it can lead to poor engine performance and triggering the ETC light.

This could be due to wear and tear, dirt or grime build-up, or mechanical failure.

Butterfly Valve Is Clogged

Usually, the Butterfly Valve is mistaken for the throttle valve itself, but they are completely different. The butterfly valve is a mechanism that pivots around an axis and this is what opens the path so the air can flow easily.

If this mechanism is clogged, it gets hard to open the throttle body and therefore no air can come through. That means the throttle body is stuck open.

Problem With Wires

Every electrical system uses a network of cables to transfer the signals between different components. Now imagine that if any of the wires between different sensors get damaged it becomes impossible to transfer the signal to the ETC control unit.

Earlier we said that the control unit is the main module that controls the ETC system and processes any necessary actions towards the valves. With damaged wires, the valves will fail to close or open leading to a malfunction in the throttle.

Faulty Accelerator Pedal Position Sensor

The Accelerator Pedal Position Sensor (APPS) is a type of sensor that detects the position of the accelerator pedal. This information is used by the ECU to control the throttle opening. If the APPS is faulty, it can send incorrect signals to the ECU, causing improper throttle control and triggering the ETC light.

Software Issues

The ECU uses software to control the operation of the ETC system. If there’s a bug or glitch in this software, it can cause the ETC system to behave erratically, triggering the ETC light. In some cases, this can be resolved by updating or resetting the software.

Keep in mind that updating or resetting the software may require professional tools and it’s better to consult with a mechanic if that’s your case.

How To Fix The Electronic Throttle Control?

Usually, the ETC system can last for the lifespan of a vehicle and it’s not a system that often goes bad. However, this doesn’t mean that it won’t.

Before we continue further, you will need an OBD2 scanner that can access the throttle unit. Not every OBD scanner has this function, so make sure to check our article on the best bidirectional scan tools. This is the easiest way to diagnose an ETC problem and will save you a lot of time.

Let’s dive into the steps.

Step 1: Diagnose the problem – How can you fix something if you don’t know where the problem is? Quickly hook up a diagnostic tool and scan the system for codes.

Step 2: Inspect the Throttle Body – Check the throttle body for any signs of damage or excessive dirt. If it’s dirty, it can be cleaned using a throttle body cleaner. If it’s damaged, it will need to be replaced. Oftentimes the diagnostic code P0121 means that you will have to change the throttle unit.

Step 3: Inspect the Wiring and Connections – Check the wiring and connections between the ETC system and the vehicle’s computer. Look for any loose connections, corroded wires, or signs of a short circuit. Any faulty wiring will need to be repaired or replaced. This will also cause the throttle control light to come on.

Step 4: Check the Throttle Position Sensor – Inspect the Throttle Position Sensor (TPS) for any signs of damage. If it’s faulty, it will need to be replaced.

Step 5: Check the Accelerator Pedal Sensor – Similarly, check the Accelerator Pedal Position Sensor (APPS) for any signs of damage. If it’s faulty, it will need to be replaced.

Keep in mind that if you are not confident with any of the steps above, it’s better to consult with a mechanic.

Electronic Throttle Control Light FAQs