Throttle Position Sensor: How it Works?

There are so many components that work in tandem to make a car run like a machine that it is; one of such components is the throttle position sensor. The throttle position sensor is an important component of a car; it plays an important role in the performance of the car. Although the throttle position sensor is a very important component of a car, it is often overlooked.

Our focus in this article will be to help you understand the throttle position sensor. We will present to you every important detail you need to have about this important component of your car. Make sure you read till the end as you’ll be learning a lot from this piece.

Throttle position sensor - How it works

What is a Throttle Position Sensor?

The throttle position sensor is a component of your car engine that serves the purpose of monitoring the air intake of the engine. This sensor is normally mounted on the throttle body. The throttle body can be located between your engine’s air cleaner and the intake manifold.

Based on its construction, we can have three different types of TPS. They are the potentiometer throttle position sensor, the closed throttle position sensor, and the combination of both these types. The second one has built-in end switches.

The performance of your vehicle is optimized by its engine control unit (ECU) based on data it collects from the throttle position sensor. The TPS is an important component of your car and so, you must pay attention to it. You can learn more about this here.

Working Principle of the TPS

Working Principle of the TPS

To monitor your car engine air intake, this part of the car monitors the position of your butterfly valve or throttle valve and sends the information to the engine control unit. The TPS monitors the length at which the accelerometer pedal has been pushed and gives the output current that determines the position of the pedal. The airflow of the engine is controlled by the position of the pedal. Make sure to check out this video, it is super helpful.

A large amount of air will be supplied to the engine if the valve is wide opened, but if the valve is nearly closed, the air that flows in will be very little. The output given by the TPS as well as other sensors are transmitted to the engine control unit; the engine control unit then decides the amount of fuel that will be injected into the engine. However, before you proceed with anything else make sure to clean your throttle body, you can learn how you can do that in our other blog post here.

Signs of a Faulty Throttle Position Sensor

faulty TPS

The malfunctioning of the TPS can lead to flashing of the "check engine" signal. It can also cause the engine to surge, idle roughly, hesitate or stall. The engine experiences these problems because the engine control module could not determine the throttle position and so, does not accurately set the fuel mixture or the ignition timing. Below are the signs of a faulty TPS.

The panel light activates: Once your throttle position sensor goes bad, the engine control unit will display a warning on the instrument panel. You can determine what the “check engine” light is signaling using a diagnostic tool.

Acceleration issues: A faulty throttle position sensor can cause different power issues. One such issue is that your engine may start up but will have very little power and so, it will shut off. Another possible issue may be spontaneous accelerations of your car even when you did not step on the gas.

The unstable engine idle: A faulty throttle position will cause fluctuating airflow and this may lead to sporadic idle conditions. When you observe your car misfiring, stalling out, or idling rough while you drive, you may need to contact a professional to check it out for you. These are signs that it may be faulty.

Unusual fuel consumption: This part of the car works in tandem with other sensors to ensure your car is driving smoothly and efficiently. When it is bad, other sensors begin to work differently to compensate for abundance or lack of airflow. One of the results of the inappropriate work of these sensors is that your vehicle will consume more fuel than it usually does. Car shakes and quakes: A faulty throttle sensor can result in your car shaking or quaking like it has an engine knock.

How to Troubleshoot It?

Troubleshoot throttle position sensor

A TPS can be tested using a scan tool, a digital multimeter (DMM), or an oscilloscope. Most DIYers prefer testing using a DMM. Check out some of these products on Amazon: To test it, you can follow any of the listed methods below. Check for diagnostic trouble codes (DTCs)Perform a visual inspection Test the TPS circuit with a DMM. You should consult your vehicle's factory manual for its recommended safety procedures.

There you may find some specific repair instructions before proceeding to troubleshoot your throttle position sensor. Also make sure to learn more about the throttle body and how you can repair it. Here you will find our article that covers that topic in more detail.

Fixing a Faulty TPS

Fix faulty TPS

If your car has a bad throttle sensor, you should make efforts to fix it. Failure to fix it may result in more damage to your car. Although you can easily replace the faulty sensor with a new one by yourself, you should consult the services of a professional mechanic. A professional mechanic will be able to provide you with a diagnosis and will also recommend or install a good replacement part.

Here on Amazon, you can get good replacement throttle position sensors. When your TPS is replaced or repaired, the trouble codes will have to be cleared and the minimum idle speed will have to be reset to factory specifications. Also, the new one placed in the vehicle should be checked for software updates. To learn more about this, check out our other blog post about throttle body here.


Drivers who have no understanding of engines and their parts may not even recognize this part of the car. The TPS, is integral for engine efficiency, safety, and fuel economy. It plays a major role in your car’s performance and so, you need to understand this component.

To enjoy a smooth ride and maintain your vehicle's optimal fuel economy, you need to ensure that your throttle position sensor is working perfectly. This sensor is key to getting your vehicle's desired power and fuel efficiency in any driving situation. Failure of the throttle position sensor will pose some safety challenge; therefore, you must make efforts to fix the sensor once you notice any of the signs mentioned above.

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