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What is a Throttle Position Sensor? A Comprehensive Guide!

What is a Throttle Position Sensor? A Comprehensive Guide!

What is a throttle position sensor? Many people might have asked this question since they are not familiar with how it works and what it does. The throttle position sensor is responsible for monitoring the position of the throttle valve. It makes sure that the engine will get the exact fuel and air mixture it needs. It works with other sensors installed in your car to ensure your engine can run at its optimal performance. It also helps enhance your car’s cruising speed, acceleration, and fuel economy.

Auto Repairs Are EXPENSIVE


When the TPS becomes faulty, it may cause some problems to occur such as difficulty in accelerating or loss of power. Your car may also surge or stall, since your engine will not be getting the right fuel and air mixture, which can compromise your safety . What is a throttle position sensor and how does it work? To know more about it, read on! We’ll tell you everything you need to know!


What is a Throttle Position Sensor: How Does it Work?



What is a throttle position sensor? How does it work and why is it important? Many car owners are probably asking these questions, especially when their vehicles are having some throttle position sensor issues.


A car is equipped with a lot of different sensors. Sensors that have various functions or tasks. They are used to monitor the conditions throughout the car’s different systems. They send the collected information to the car’s onboard computer so it can adjust the performance specifications of the car and the throttle position sensor is one of them.


What is a throttle position sensor? A throttle position sensor or TPS is responsible for keeping an eye on the throttle valve position in internal combustion engines. It helps the fuel system get the right amount of fuel and air mixture, depending on the throttle’s position and the other data sent by the other sensors placed throughout the car.


A throttle position sensor can be usually found on the throttle valve spindle, making it easier to have access to and monitor its position. Many throttle position sensors equipped in vehicles are 3 wire potentiometers. This type of TPS has a power supply, usually of 5 volts, a ground, and a signal return wire. A potentiometer TPS sensor can provide a variable resistance which can vary depending on the throttle valve’s position.


The throttle position sensor sends data to the car’s onboard computer about the rate of acceleration, deceleration, idling, and the fully open throttle valve state. Like mentioned earlier, cars usually have a throttle position sensor that is a 3 wire potentiometer. The first wire has a +5 voltage applied to the sensor resistive layer. The +5v  is the reference signal sent by the onboard computer which enters the throttle position sensor. The second wire is the one that closes the sensor circuit to the ground. The third wire is used for the output. It is the reference signal going through a variable resistance that decreases to a new voltage which will then be sent back to the car's computer.


The onboard computer, upon receiving the data or voltage, will be able to determine or identify the throttle position. The onboard computer is capable of calculating the idling or when the voltage received is below 0.7v, the full load or when the voltage received is about 4.5v, and the throttle valve opening speed.


When the voltage received reads a full load state, the onboard computer will adjust and allow further enrichment of the fuel mixture. When the TPS detects that the car is in deceleration mode since the throttle valve is closed and the engine speed is above certain RPM, the car’s computer will shut off the fuel injection. When the engine speed reaches its idle value or when the throttle valve is open, the fuel supply will then be resumed right after.


There are some cars that enable you to adjust these values. However, bear in mind that it is critical to have a proper adjustment. A throttle position sensor that is misadjusted can lead to stalling, poor idling, loss of power, and transmission shifting issues.


What is a throttle position sensor? Basically, the TPS  sends data to the car’s onboard computer. The car’s computer will then use the received data from the sensor as an input to its control system and will adjust or alter the ignition timing and fuel injection timing depending on the throttle valve position as well as the rate of change of that position.


What is a Throttle Position Sensor: What Will a Bad Throttle Position Sensor do?



What is a throttle position sensor? You may now have an idea what it is, what it’s for, and how it works. But what happens when it becomes bad or faulty? Since a throttle position sensor plays a very important role in the overall function and performance of a car, when it becomes bad, your car may suffer some consequences and experience some problems.


Issues with your car’s throttle position sensor can occur as your car ages or as it reaches certain mileage. The older the car gets, the more problems can occur, especially if it is not well-maintained. But when it comes with your throttle position sensor, the older your car gets, the less efficient it will become. This can happen since oil and carbon build ups can develop over time. It is for this reason why you need to have all your car’s sensors checked regularly.


You will know if your throttle position sensor has become faulty when you experience any of these symptoms:


  • Illuminating check engine light


Your car is installed with an onboard computer which means that it is capable of constantly receiving a lot of data or information from all the different components and sensors positioned throughout your car. If any of the sensors detect suspicious or unusual data, the computer will think that there is a problem and it will automatically set off your check engine light.


An illuminating check engine light can be caused by a bad TPS but it can also be caused by other problems. It is best that you take your car to a mechanic and have it checked so you will know what triggered it. You can also check for any stored diagnostic trouble codes by using a diagnostic scan tool.


  • Uneven idling


Uneven or irregular idling is one of the problems you may encounter when you have a bad throttle position sensor. This can happen when the TPS is sending wrong data to the car’s onboard computer which means that your system is not getting a constant level of fuel or air which is needed to maintain a steady idle. The moment you experience this problem, you need to have your car checked to correct the problem and to prevent further damage.


  • Lack of power


When you ask, “what is a throttle position sensor?”, you will know that it helps your engine run at its optimal performance by making sure that it gets the precise fuel and air mixture it needs. If the TPS becomes faulty, your engine may not be getting enough fuel or may be getting too much. When this happens, you will notice an obvious lack of power.


You may notice that your car is not accelerating like it’s supposed to. You may find it hard to speed up when you step on the accelerator pedal. A faulty TPS may be sending incorrect data to your car’s computer which confuses it, causing it to send too much or too little fuel or air to your engine. You want to accelerate so you step on the gas pedal, the engine is asking for more fuel, but it is not getting any.


  • Poor fuel economy


If you notice that you have to frequently make a trip to the gas station, you might be dealing with a faulty throttle position sensor. Increased fuel consumption is one of the most common symptoms of a faulty TPS. This can happen when the car is running too rich or is using too much fuel. Your engine doesn’t really need the excess fuel but since the TPS is sending wrong data to the car’s computer, it will deliver fuel to the engine based on the said data. Poor fuel economy can also be caused by other problems such as dirty or clogged fuel injectors and faulty spark plugs. To determine what really caused the problem, you will have to take your car to a mechanic and have it inspected.


  • Car speeding up on its own


Car speeding up on its own can be a dangerous symptom of a faulty throttle position sensor. Your car may accelerate on its own even if you have no intention to speed it up. The jerking can happen when your TPS is sending data readings that are over the place or when it's not sending data at the right time. It is important that the moment you experience this problem, take your car to a mechanic immediately since it can compromise your safety if left ignored.


  • Difficulty in shifting gears


This problem usually happens on cars with automatic transmissions. When you find it hard to shift gears or when it does not shift properly, it can be an indication that you have a faulty throttle position sensor. This can happen since the transmission and the engine should always be working together during gear shifts.


  • Car in limp mode


When you are driving and your throttle position sensor suddenly becomes faulty, your system can detect it and your car may go into limp mode. This is done since your car may not be safe to drive anymore and to prevent further damage. Many modern vehicles have this feature and it allows the drivers to drive their cars at very low performance. Just enough to get off a busy highway and find a safe spot or reach an auto repair shop to have it checked and repaired.




What is a Throttle Position Sensor: How Do You Fix a Throttle Position Sensor?



We have already discussed the answer to the question, “what is a throttle position sensor?”. We now know why it is important to have a good, working TPS. But what if it becomes faulty, how do you fix a throttle position sensor?


If you experience or notice any of the symptoms of a faulty throttle position sensor, you should have it repaired immediately. Mechanics may recommend a sensor replacement to prevent potential problems later on. However, there are some TPS issues that can easily be repaired by just doing some resetting or by repairing the sensor.


  • Resetting or reprogramming the TPS


Sometimes, resetting or reprogramming the TPS can fix some of its issues. Resetting can also be done when you have a newly-installed throttle position sensor. To reset a TPS, you just need to disconnect the battery’s negative cable for up to 5 minutes. You can also remove your engine control unit or ECU’s fuse to reset the TPS.


If you don’t know your way around cars or you are not comfortable working with electricity, just let a profession handle the resetting. If you try to do it yourself and you end up removing the wrong cable or fuse, it will be dangerous since it can harm you and your car. Resetting can help fix your sensor since code errors can sometimes cause your TPS to work incorrectly or erratically. But if resetting won’t fix the issues, you may have to reprogram your TPS.


  • Repairing the TPS


Repairing a faulty throttle position sensor usually involves checking and tightening loose connections or wirings. You just need to inspect your TPS for any signs of damage such as corrosion or bad connections. Replace or tighten them if needed.


  • Replacing the TPS


If your sensor has damages that can longer be repaired, you have no choice but to have it replaced.



What is a throttle position sensor? It is a very important component of your car’s fuel system. It ensures that your engine will be getting the right fuel and air mixture to make sure that it is always running and accelerating smoothly. If you experience any problems with your TPS, do not ignore it but have it checked immediately to avoid further damage.