Throttle Position Sensor Test – Quick Check with Multimeter

Throttle Position Sensor Test

Throttle Position Sensor is an essential electrical part of your car. It keeps track of an engine’s air intake. TPS is usually positioned on the throttle body’s butterfly spindle, commonly referred to as the butterfly shaft. It feeds the data to your car ECU despite your throttle valve openings. The fuel management system of the car depends on the throttle position sensor (TPS). So, if it fails, the automobile won’t have enough power and may shut off on its own.

So, you should check and perform the throttle position sensor test continuously to address any malfunctioning in the early stage.

Step By Step: Throttle Position Sensor Test

how to test throttle position sensor

The key role of the TPS is to maintain the proper amount of air passage to the engine. When the driver presses the gas pedal, the throttle valve opens. Here TPS comes into play. The engine intake manifolds adjust themselves with the help of TPS. This vital sensor mixes the air and fuel in the right proportions. TPS is connected to ECU and helps in achieving smooth acceleration.

The following is the process of carrying out a throttle position sensor test with a multimeter.

Locate the TPS

The housing will be the starting location of the fuel line’s branch. There will be a device with cables connecting to the engine control unit and fastened to the throttle body (ECU). Here, you can find the sensor for the throttle position.

Since all cars use the same color or wires, finding the power, ground, and signal cables come next.

Clean the Carbon

After opening the hood and locating the sensor, the next thing you should do is clean the housing. Inspect the throttle plate and walls for carbon build-up. Lastly, inspect the throttle position sensor on the side of the throttle body.

Ground Connected TPS

If your TPS is in a ground connection, you must unplug the electrical connector first. Must remove any sort of contamination.

  • Set the digital multimeter to around 20 volts on the voltage scale.
  • Turn the ignition key to the ON position after the voltage has been established.
  • Connect the lead to the positive battery terminal.
  • After this, verify the throttle position sensor by connecting the black test lead to the three electrical connections.
  • The wiring is defective if the terminals do not read 1 volt.

TPS in Connection with Reference Voltage

You must follow different procedures while learning how to conduct the throttle position sensor test. So, if your TPS is linked to the reference voltage rather than to the ground, here are the steps to carry out the throttle position sensor test.

  • You must first attach the black lead of the digital multimeter to the ground terminal of the throttle position sensor.
  • Next, switch the ignition to the ON position without switching ON the engine.
  • Now, join the red test lead to the other two terminals.
  • The throttle position sensor is in good operating condition if one of the terminals displays 5 volts.

Evaluate the Signal Voltage

If the throttle position sensor test was successful with the reference voltage technique, you should carry out a few more steps to confirm it.

  • Re-check the connector’s ground and signal terminals.
  • Connect the multimeter’s red lead to the signal wire, and its black test lead to the ground wire.
  • Make sure the throttle is closed all the way before turning the key on without starting the engine.
  • The TPS is operational if the digital multimeter registers between .2 and 1.5 volts.
  • The digital multimeter’s reading should rise to 5 volts when you open the throttle plate.
  • You should replace it if the test for the throttle position sensor fails to reach 5 volts.

How to Test Adjustable Throttle Position Sensor?

Adjustable throttle position sensors are those which can be loosened and set by turning them to the left or right to get the right readings. So, here are quick steps.

  • Firstly, loosen the mounting bolts that secure it to the throttle’s body.
  • Re-check the terminal while the sensor is still in connection with the throttle.
  • Connect the positive lead of the multimeter to the signal terminal and the negative lead to the ground TPS terminal.
  • In the next step, turn the TPS right or left until it gives the correct readings. Ensure that the ignition is in the “ON” position. Also, close the throttle plate.
  • When you achieve the right reading, place the TPS in that position and tighten the bolts. When your TPS isn’t giving the desired reading even after multiple position checks, then it is time to replace it.

TPS Diagnostic Trouble Codes

Knowing what are the various throttle position sensor DTC will help you avoid wasting time and, more significantly, changing unnecessary parts. Here are some common TPS DTCs.

P0123Sensor ground open. The sensor is incapable of a 5V voltage.High voltage TPS problem
P0122Circuit open. Ground shorted circuit.Low voltage TPS problem
P0121Defective speed sensor signal. Defective MAP sensor. Defective TPS.TPS signal conflicts with MAP signals

What Are the Symptoms of Bad TPS?

Symptoms of Bad TPS

Here are a few basic symptoms that indicate that the TPS isn’t performing at an optimal level.

Check Engine Light

The first indication that there is a problem with the TPS sensor is typically the check engine light. When the check engine light on your car dashboard is ON, take it seriously.

Unsteady Idle

It might be time to replace the transmission position sensor if your car can’t idle at a constant speed.


One of the most apparent symptoms of a bad TPS sensor is jerking. When the engine control module isn’t receiving accurate information regarding the air intake, it does not send the correct amount of fuel, causing jerkiness.

Having trouble changing gears

Whether you’re operating an automatic or stick-shift vehicle, your vehicle must switch gears correctly. Your shifting will have certain issues if your TPS sensor is broken.

A defective TPS sensor will cause poor mixing of the air and fuel and ultimately deteriorate your car engine, leading to the replacement of your car engine.

How to Reset Throttle Position Sensor?

If you are looking to reset the TPS, then no need to worry, as it is an easy process. In most automobiles, the reset button is beneath the steering wheel.

  • Don’t start the vehicle and turn the key in the ON position.
  • Press the TPMS until the light near the tire pressure indicator blinks three times.
  • Start the engine and wait for 20 minutes. It will be reset.

Throttle Position Sensor- FAQs

How to test the Throttle Position Sensor?

Here are four easy steps to test TPS with a multimeter.
➢Firstly, inspect for carbon buildup.
➢Connect the TPS to the ground wire and evaluate the reading.
➢If your car TPS is connected to reference voltage, check it is giving 5V volt reading.
➢Check and confirm that the TPS is generating a proper signal voltage when the engine is ON and OFF.

What are the signs of a failing Throttle Position Sensor?

Here are some signs which indicate that your car has a defective TPS.
➢It won’t idle smoothly
➢Lack of power
➢Fail shifting of gears.
➢Check Engine Light ON.
➢The car will have uneven acceleration.
➢Reduced fuel economy

Do throttle position sensors generate error codes?

If the voltage value is absent, irregular, or slow, a defective TPS can produce a trouble code in the odometer. The ECU will turn on your check engine light in case of a defective TPS.

Can we repair the faulty TPS?

Sometimes your TPS requires only reprogramming or resetting to fix the problem. However, when your TPS is broken and, even after multiple resetting, it isn’t responding, then it is best to replace it. It is not worth repairing a broken sensor.

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