How to Fix the Electronic Throttle Control of a 5.7L Hemi (DIY Method)

A common problem encountered by owners of Hemi 5.7L trucks is the sudden flashing of the ETC light. When this problem occurs, it's a clear indication that the electronic throttle control (ETC) is either broken or malfunctioning. Therefore, you need to consider repairing it.

Learning how you can repair a 5.7L Hemi with electronic throttle control isn't the easiest of tasks. And there are many reasons for ETC failure. The problem can be manifested in many different ways, so you must proceed accordingly.

However, you don't need to worry if you don't know where to start. We will show you exactly how to fix the electronic throttle control 5.7L Hemi. Below, we will cover the most common fixes so that you can properly resolve the issue on your own. So let's have a look by starting with an explanation of the electronic throttle control.

What is an Electronic Throttle Control?

Before you can effectively know how to fix the electronic throttle control 5.7L Hemi, it's important to first understand the ETC (Electronic Throttle Control). This is the "fly-by-wire" system in the automotive industry.

In the ETC system, the vehicle's electronic control unit uses information from the following:

  • Accelerator pedal position sensor (APP sensor)
  • Throttle position sensor (TPS)
  • Vehicle speed sensor
  • Wheel speed sensor

There are various other sensors to determine how to adjust only the throttle body.

So let's take a look at the two main sensors that make up "Fly by Wire":

  • Accelerator pedal position sensor
  • Throttle position sensor

Although many people think that car sensors are small plastic clips with all kinds of complexities, what actually happens inside is really quite simple. First, both sensors work together to change your input to the movement of the throttle plate.

Until now, these sensors used potentiometers that acted as dividers for voltage. This divider uses resistive elements and wiper arms to "divide" the input voltage (known as the reference voltage). Then they transfer this voltage to your Hemi's computer, which then adjusts the throttle's position.

Now, let's examine how the APP sensor serves as a divider. Any time you step on your accelerator pedal, you cause the wiper arm to move closer to the reference voltage terminal of the resistance element (Vref).

In doing so, you can reduce the resistance that the current needs to flow through until it can reach the wiper arm. As such, this will increase the ECU voltage output. The exact relationship between output voltage, reference voltage, and wiper arm position can be written as an equation:

Determining this equation is actually quite easy. It requires using Ohm's law and Kirchhoff's voltage law. Let's ignore this derivation because the key is understanding the concept. ECU provides the reference voltage for the APP sensor.

The physical pedal movement moves the wiper to the resistive element and changes the voltage output of the ECU. Then, the ECU receives a signal and directs it to the proper signal to the throttle's actuator, which then works to move your throttle plate.

Furthermore, the throttle's position sensor functions similarly. The potentiometer's wiper is joined to the main shaft of the butterfly valve. When this valve opens or closes, it will change the voltage output from 0 to voltage reference. This voltage output gets sent to ECU, which is how it knows which position to align your throttle plate.

A common issue with potentiometer sensors is when the resistive element and wiper arm come into contact with each other. If this happens enough, they will ultimately wear out.

Fortunately, newer accelerators and throttle sensors do not have this issue because they use the Hall Effect. This serves as their fundamental working principle. These types of sensors include transducers that change an external magnetic field into voltage.

So with magnets on the throttle shaft and pedal serving as reference points, Hall sensors will output different voltages according to the magnetic field's strength. When the throttle or accelerator moves, the magnet also moves. This movement alters the strength of the field, thereby changing the voltage output from your sensor to your ECU.

We can now examine how these sensors interact with each other. The ETC system is closed loop. The throttle is opened according to user input. This is transmitted to the electronic throttle control through the accelerator sensor. It is adjusted according to the reading of the TPS, which measures the butterfly valve's position.

Check out this feedback loop pictured above. If you have to suddenly step on your accelerator for any reason, the position sensor for the accelerator will provide a "reference input" to the ECU. This is simply a voltage range of 0 to Vref.

The input reference shows you where you really want the throttle. The ECU, on the other hand, serves to interpret the signal and then activates the motor to open or close your vehicle's butterfly valve.

The calculated output is the location point of the throttle valve after the initial movement of the actuator. This position is communicated to your Hemi's computer through the output voltage of the throttle position sensor.

The difference between the position where you want the throttle as shown by the APP sensor and the current position of the throttle as shown by the TPS is the measurement error.

Moreover, the computer examines this error and then sends a suitable new signal to the throttle motor to make the throttle reach the driver's desired position. The new position then gets read by the throttle position's sensor. This results in the process cycle continuing.

One of the main advantages of this system is it can easily integrate systems such as brake override, adaptive cruise control, and electronic stability.

Today's Fly-by-Wire systems come with multiple TPS and APP sensors, and if there is a difference between the redundant sensors, a fault code will be thrown.

Symptoms of a Bad Electronic Throttle Control on 5.7L Hemi

At this point, you should have a pretty good understanding of the electronic throttle control. As you can imagine, there are a number of potential issues that can arise from the ETC in your Hemi. So let's start with some of the most common and explore ways to resolve them. From the dash warning lights to mileage problems, you have many ways to determine if something is wrong with the ETC.

Lighted ETC Danger

Your Hemi 5.7L has a check engine light for the ETC that will flash when it is not working properly. The ETC light is the most accurate way to know what your truck needs to be inspected. However, this check engine light may not occur all the time.

Or the engine light may eventually happen too late, which is often the case. Therefore, it is always important to understand other ways to check this check engine light, which we will explain below.

Less Power

A great way to know if ETC is not working right is to check if you are receiving the same power by pressing the pedal. If there is a slight drop in power every time you depress the pedal, your ETC is likely to malfunction.

This occurs because ETC fails to calculate how much air is entering the engine. In some instances, however, this happens due to the throttle body automatically reducing how much air is entering your Hemi's engine when it wears off.

Slow Acceleration

Similar to the loss of engine power, there may be problems when accelerating. In some instances, you might not be able to exit the idle state. This occurs whenever the throttle system limits the speed of air entering the engine automatically.

To stop further damage, the engine works as slow as possible. This means that the idle speed is accelerated. When this occurs, if you pedal hard enough, you can still drive the truck and get a certain acceleration. But this is risky, as it shows that the throttle body isn't working properly and will stop soon.

Less Mileage

Controlling the amount of air entering the engine is a big part of how to fix the electronic throttle control 5.7L Hemi. The ETC accounts for the amount of air entering. Therefore, when it starts failing, you will lose acceleration, overall power, and MPG efficiency.

If you feel the vehicle rushing through the fuel tank quicker than usual, it indicates that the ETC is allowing too much fuel in your engine. If it is not repaired quickly, this can be very expensive.

Another possible reason this might happen is that your ETC does not allow you to accelerate fast. As such, the engine still consumes a lot of gasoline. However, it consumes the same speed as it is. So it feels as if your vehicle is consuming too much gasoline.

Poor Idling

Another typical symptom of ETC failure is abnormal idling speed. This is easy to detect even if you turn on the engine. Although the car may start without a problem, leaving it idle either suddenly stops working, or it starts to feel almost like it shuts down automatically.

This symptom is a direct way to know that the ETC is about to stop working because it means that the damage is sufficient to affect the performance of the car without even accelerating.

Pedal or Engine Stoppage

When ETC corruption is almost irreversible (in most cases), what you encounter is close to the maximum risk. As such, not only will you experience idling, acceleration, and power issues, but the pedals may stop working, as well.

In most cases, this can be very dangerous. What's more, the engine might suddenly stall. It will start to decelerate automatically even when stepping on the pedal. Therefore, you should repair any electric throttle system errors immediately.

What Causes a Bad Electronic Throttle System?

Knowing how to fix the electronic throttle control 5.7L Hemi is not easy without first knowing the cause of its failure. This is why you must always check for any of the following common issues:

  • The throttle body is rusty
  • Vacuum or air filter leak
  • Loose sensor or electrical connection
  • Serious physical damage to the throttle system

Fortunately, you can fix some of these issues. But others aren't fixable, so you have to replace the ETC and other possible parts. But don't despair, as we have the answers to these problems and can help you get back up and running.

How to Fix the Electronic Throttle Control of a 5.7L Hemi (DIY Method)

Knowing how to fix the electronic throttle control 5.7L Hemi is essential. Here, we will show you how to fix the electronic throttle control on your Dodge Ram.

After understanding the causes and various symptoms, it is much easier to see the solutions. However, if you have a different truck or engine, don't worry. You may still find these techniques worth trying. Remember to follow our recommendations. So let's jump right into it.

Clean the Throttle Body

As stated, rust is one of the most common causes of throttle body failure. solution? Remove rust completely. Any time rust covers the throttle body, the valve will not move normally. And as a result, air will not enter the engine as intended. This obviously causes problems.

It is usually recommended to use throttle body cleaner or rust remover spray.

Reconnect Everything

In some cases, there is no need to worry about physical rust or damage. But if the sensor or cable is loose, you need to address it. The answer is to reconnect it and look to see if the system is functioning as normal. You can normally find the sensor located near the throttle body. It is necessary to check if everything is properly connected and connected.

One way to do this job better is to first disconnect the sensor, as well as the throttle body. Then you need to clean and reconnect them. Make sure there is no looseness. This may solve the problem.

Change the Hose

If you checked the throttle body and sensor, but everything seems to be fine, then you might also check for those problems. This pipeline connects the engine computer to the throttle system. When it fails, throttling will be affected.

First, it is enough to check if it is properly connected (you may find it loose). But in most cases, the hose has broken and leaked. So you must replace it. If you are a beginner, this may be a bit difficult. However, once you have a replacement hose, it usually takes no more than 10 to 20 minutes.

Reset the Throttle System

In the end, it may not even be a physical problem, but an error in the computer system. When this happens, the ETC may start to malfunction even if everything seems to be connected correctly and in pristine condition.

What is the solution to this situation? Quite simply, resetting the entire throttle system and computer may solve the problem. Why is it effective? Because the problem may be related to the code problem on the electronic system. In short, ETC mistakenly sensed that there was a problem and started to malfunction.

The following is a solution to this problem:

The gentle method is to turn the ignition key without starting the engine. After a few seconds, start depressing the pedal and press your feet on the pedal for 5 seconds. Then release and press again for 20 seconds. This should reset the ETC system.

If the previous method does not work, another thing you can do is to remove the ETC and sensor from the truck. Then disconnect the battery for a few minutes (at least 10 minutes). Then start the engine and see how it performs.

If none of these methods seem to solve the problem, then you may need to manually replace the throttle system.

How to Replace the Throttle System

When the problem does not seem to be solved after you have tried all the methods, there is nothing more effective than replacing the entire throttle assembly.

Replacing this part is not something that beginners will find easy. But it is not too difficult. Therefore, anyone with good mechanical experience can complete the work in less than an hour.

Here are some steps to follow:

Find the Throttle Control

If you are just starting to repair things in a truck, you will not know where the throttle body is. Don't worry, it looks like a pump, directly connected to the throttle sensor and air filter. You can find it on or near the top of the engine.

In most Hemis, it is covered with plastic or metal. Therefore, although the cables and pipes will come out from the inside, it looks like a small box.

Take the Throttle Cover Out

Simply use a screwdriver to remove the throttle cover. Sometimes, a wrench is needed, as well. Disconnecting the cover will loosen the throttle body.

Unplug Everything

Then continue to disconnect all connections. This includes the hose at the connection of the air filter and the wire from the sensor on the other side. Then continue to disconnect the rest of the body by removing the bolts. For this, you may need a wrench. Finally, remove the throttle body.

Install the New Body

With the free space that the new throttle body enters, setting it shouldn't be a big problem. If you have the correct throttle body, this should take 5 to 10 minutes to set. Just follow the same deletion process, but backwards. Then screw in the bolts, reconnect the hoses and wires, and then put the cover back in place. Then you are done.


Frequently Asked Questions (FAQs)


How much to fix electronic throttle control system?

This is a pretty expensive fix. You're looking at around $650 to $700.

Should I take my Dodge RAM to a repair shop?

If you are unable to resolve the issue on your own, then yes. You can save a lot of money by fixing the throttle body and other issues by yourself, however. So if you are able to work on your Hemi, you should attempt to do so before taking it to the shop.

How do I reset my electronic throttle control manually?

Manually resetting the ETC (electronic throttle control) can be difficult. First, you need to make sure that you have the accelerator pedal completely depressed. Then, turn on the ignition switch, then switch it off. Wait ten seconds. While you’re waiting, make sure that the throttle is moving. You can do this by listening to the operation sound.

How do I fix my electronic throttle control system?

If you can connect your truck to a computer, you can get a diagnostic of the main throttle body issue. If not, you may need to have your vehicle towed to the nearest repair shop.

What happens when the electronic throttle control goes bad?

Your throttle body won't work correctly, thus preventing you from driving your vehicle. If it won't shut and stays stuck open, you could be looking at a serious issue.

How do you reset the throttle body on a 5.7 Hemi?

If you wish to reset your Dodge Ram’s TPS (throttle position sensor), first switch on your ignition without applying the brakes. This ensures that the engine will not start. Press in on the accelerator for approximately 15 seconds. Lastly, let off of the accelerator and turn off the engine. Now just restart the engine. You are safe to drive with a reset throttle body.


Your Hemi's throttle body is an essential component of your vehicle. If it isn't functioning properly, you could be looking at an expensive fix. Knowing how to fix the electronic throttle control 5.7L Hemi is your best bet. In doing so, you can save a substantial amount of money.

Taking your Hemi to the repair shop to have the throttle body fixed can be a costly endeavor that is best avoided when possible. However, you may have no other options but to do just that. It's best that you act quickly, too. Putting the problem off can lead to even more damage and costly repairs. As such, you may just need to get a new throttle body.

The sooner you take your truck in and have the throttle body problem resolved, the safer your vehicle will be. It will be pricey, but the repairs will be worth it in the end.

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