What is a Throttle Position Sensor(TPS)?

The Throttle Position Sensor moves with the throttle and sends a voltage signal to the computer indicating throttle angle and speed of movement data.

The computer uses this data to measure engine load, adjust timing, fuel delivery, EGR, and converter clutch operation, and clear flood mode.

What is a Throttle Position Sensor?

The throttle position sensor monitors how far open the throttle valve (or blade) is open, which is determined by how far down the accelerator pedal has been pushed.

The throttle position controls the amount of air that flows into an engine’s intake manifold; when it’s opened wide more air flows in; when it’s nearly closed, little air flows in.

The position of the throttle and how quickly it’s opening or closing is transmitted to the engine control module, and that information is among the factors the computer uses to decide how much fuel is injected into the engine and the spark timing.

The TPS is usually mounted on the throttle body (the housing that contains the throttle valve).

When a TPS malfunctions it can trigger a “check engine” warning light or cause the engine to idle roughly, surge, hesitate or stall because the engine control module doesn’t know what the throttle position is and can’t correctly set the fuel mixture or ignition timing.

Why Is the Throttle Position Sensor Important?

The throttle controls the engine’s air intake. It ensures that the right amount of air reaches the cylinders, mixing with the gasoline sprayed by the fuel injectors to make the optimal fuel-air mixture.

If the engine receives more air than it needs, it will run lean. Burning a lean fuel-air mixture will cause problems like poor fuel economy, reduced engine power, and hesitation during acceleration. Running lean can also cause engine pinging.

Conversely, the engine will run rich if it doesn’t get enough air. Running on a rich fuel-air mixture also causes issues, such as fuel wastage and rough idling.

Whether it runs lean or rich, an engine that doesn’t receive the correct fuel-air mixture will wear out faster. Critical components like the spark plugs can fail earlier, which might cause severe damage to the engine.

To avoid either scenario, the PCM relies on the throttle position sensor to gauge how much air enters the throttle. Based on the sensor’s readings, the computer module will release the appropriate amount of fuel to create the optimal blend.

How Throttle Position Sensors Work?

Throttle position sensors work by measuring the angle of the throttle plate or lever and transmitting this data to the ECU. There are two main types of TPS: potentiometer-based and Hall effect-based.

Potentiometer-based TPS: This type of TPS consists of a variable resistor that is connected to the throttle shaft. As the throttle is opened, the resistance across the potentiometer changes, which provides a voltage signal to the ECU. The ECU then uses this signal to determine the position of the throttle and adjust fuel injection accordingly.

Hall effect-based TPS: This type of TPS uses a magnetic field to detect the position of the throttle. A small magnet is mounted on the throttle shaft, and as the shaft rotates, it passes over a Hall effect sensor, which generates a voltage signal. The ECU then uses this signal to determine the position of the throttle and adjust fuel injection accordingly.

Common Problems with Throttle Position Sensors:

There are several issues that can arise with throttle position sensors, including:

• Erratic idle: If the TPS is faulty, the engine may idle erratically or even stall.
• Hesitation during acceleration: A faulty TPS can cause hesitation or jerk during acceleration.
• Poor fuel economy: Incorrect signals from the TPS can lead to poor fuel economy due to improper fuel injection.
• Check Engine Light: A malfunctioning TPS can trigger the check engine light to come on.

Symptoms Of A Bad Throttle Position Sensor

There are many symptoms of a failed throttle position sensor. While some of these symptoms could also be signs of other engine issues, watch out for these symptoms of bad TPS, or throttle position sensor.

The most common symptom is your check engine light. This indicator is a vague symptom, as it could also point to a variety of issues, but you can expect to see it if there’s any issue with your throttle position sensor.

Next, any unusual changes in your acceleration could be linked to this sensor. During your normal driving, consider inspecting your sensor if you experience any of these throttle position sensor symptoms:

• Hesitations during acceleration
• Difficulty and/or delay in gear shifting
• Unusual surges while accelerating
• An unexplainable bucking and jerking in the vehicle
• Sudden idle surges
• Sudden engine stalling without any apparent reason
• Sudden surges in speed while driving on the highway
• Intermittently flashing of check engine light for no apparent reason
• A drastic drop in fuel economy
• Poor power

Each of these could be a sign that your throttle position sensor isn’t working correctly. Too much airflow or too little could cause poor acceleration performance, but it could also be linked with other engine issues.

If you notice your fuel economy has dropped dramatically, it could be a result of an improper fuel and air mixture.

Similarly, if your engine struggles to idle efficiently, it could also be a result of a damaged throttle position sensor. Stalling, surging, or hesitating while idling all can be caused by this unassuming sensor.

The best way to determine if these issues are caused by your throttle position sensor is to go to the source. By using a multimeter, you can determine if the sensor has an electrical connection issue.

Check the engine control module for the trouble code that resulted in your illuminated check engine light to see if it is linked to your throttle position sensor.

How to Reset a Throttle Position Sensor?

There is no “one size fits all” method to reset a throttle position sensor. Years ago, resetting a TPS involved using a multimeter to read the sensor output while loosening the sensor itself and turning it slightly on its mounting pad to reach a certain output value.

The easiest way to reset your throttle position sensor is to unhook the negative cable from your battery for up to five minutes or to remove the fuse for your engine control module.

Don’t attempt this if you’re uncomfortable working with electricity, as removing the wrong fuse or cable from your battery could be dangerous.

Resetting is sometimes all that is required to restore your sensor. Code errors can cause your throttle position sensor to work erratically or incorrectly. Otherwise, you’ll need professional software to reprogram your sensor. A professional mechanic best does this job.

Most modern methods involve turning the ignition key off and on while pushing the gas pedal to the floor in a certain sequence. Others require specific diagnostic equipment to interface with the onboard computer.

Some of these techniques are technically a throttle recalibration, but many people refer to it as a throttle position sensor reset anyway.

How To Replace Your Throttle Position Sensor?

#1. Removing Your Sensor.

Follow these steps to replace your sensor. First, find the sensor. It should be mounted to your throttle body, which is on top of your engine.

You should disconnect your negative battery cable before removing the sensor. This helps you avoid the risk of electrical shock or causing an error code on your engine control module.

Your throttle position sensor should be attached using electrical connectors. These connectors are easy to remove using the tab on the side.

Once the electrical connectors are removed, look for the mounting screws on your sensor. Carefully unscrew and remove your throttle position sensor.

Be sure to read your owner’s manual and compare it with your current sensor when shopping for a new one. Shop at your local auto parts store to find a quality brand or exact OEM match.

#2. Installing a New Throttle Position Sensor.

Install your new sensor by working backward through the removal steps. Start by installing the sensor using the mounting screws.

Next, connect your sensor to your vehicle electrical system using a convenient electrical connector. You should be able to easily push it together and hear a distinct click. Check to ensure a firm connection.

Connect your battery and prepare to double-check your work. Start your car and test the idle and acceleration. Depending on your vehicle and the sensor you’ve installed, you may need to manually adjust the sensor.

Other options automatically adjust to offer your car the optimal levels of air and fuel for a smooth idle and powerful acceleration.

FAQs.