How To Test a Ford Mustang TPS Sensor

How To Test a Ford Mustang TPS Sensor


The throttle position sensor in your Ford Mustang is designed to read how far your throttle has opened. By determining the angle of your throttle body opening, your Ford Powertrain Control Module or engine computer knows how much air is entering the engine. Based on these values from your Mustang TPS your PCM delivers the right amount of fuel.

Your Mustang TPS is basically just a potentiometer that is mounted opposite of your throttle blade. As you push down on your accelerator pedal, the metal wire pulls open on this throttle blade which opens your throttle body. When your Mustang TPS goes bad, or suffers an internal issue, your Mustang will not run right.

Today I’m going to show you how to test your Mustang TPS in a 1992 Ford Mustang GT. This generation of Mustang is also known as the fox body. It’s equipped with a HO 5.0 liter engine, and is a very popular modified chassis, despite it’s age.

How To Test a Ford Mustang TPS Sensor

This throttle sensor is connected by way of the Ford engine harnesses of this generation. These are easy to identify but also notoriously inconsistent. These “salt and pepper” engine harnesses should be tested carefully.

In order to complete this Mustang TPS wiring guide, you will need a digital multimeter. It’s always important to be gentle with your multimeter leads, and especially so in this generation of Ford Mustang.

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If you are looking for the next generation of Ford Mustang throttle position sensor, check here for our How To Test a Ford Mustang TPS.

Symptoms of a failed Ford Mustang TPS

You are going to have a lot of issues with your 5.0 liter engine when this sensor goes out. Many of these symptoms can range from poor throttle response, or uncontrollable engine RPM. When you have a faulty TPS, it’s best not to drive your Mustang until you’ve tested and replace it.

  • Engine revs on it’s own
  • Bad throttle response
  • No response from throttle
  • Poor idle

When you have any of these problems, you can use this Ford Mustang TPS tutorial to help you fix the issue. To test your throttle position sensor, you’ll use your multimeter to test the engine connectors with your key turned to the “ON” position.

Testing your Mustang TPS for Power

The first wire you’ll be checking in this How To DIY guide is check the throttle sensor for power. Make sure your key is turned to the “ON” position before starting. Locate your throttle position sensor and disconnect the harness.

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Once you’ve disconnected the throttle sensor, gently probe PIN A or the RED or ORANGE wire. This is the switched power that sends a 5 volt DC signal to your throttle body. Have power here? Good! Now check PIN C for a low reference ground signal, which is a GREEN or BLUE wire.

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If your Mustang TPS checks out and your multimeter has the capability to do so, you can test PIN B which is the signal wire. You can also try tapping lightly on the Mustang TPS to see if that will help matters.

Testing your Mustang TPS Signal

PIN B is a BLACK wire and it’s the signal wire that sends the voltage back to your Ford PCM. In order to test the signal from your throttle position sensor, you’ll need to reconnect the TPS.

Now using your multimeter, pierce the BLACK wire or PIN B from behind the engine connector. Remember that your Mustang TPS should be plugged in for this part of the test.

With the throttle blade closed and the key turned to the “ON” position, this wire should be sending out between .9 to 1.5 volts of DC signal. Now manually crank open your throttle blade to the WOT (Wide Open Throttle) position. At this position your signal should read between 4.5 to 5.0 volts.

Slowly modulate the throttle closed and open, and monitor your signal. It should be smooth and without gaps or spikes as you close or open the throttle body. If any of your Mustang TPS readings are outside of these parameters, it’s time for a throttle position sensor replacement.

Of course there’s always a case of your engine harness acting up, which as we said previously is a common issue. If this remains an issue use automotive dielectric grease to help matters. Remember that these salt and pepper style engine connectors are known for failure or intermittent wiring issues.

Using a silicone-based grease can prevent corrosion and help your engine connectors work properly. If all else fails you will need to replace your throttle sensor. Have any questions about this Mustang TPS DIY tutorial? Leave them for us below and let us know!