How To Know Your Throttle Position Sensor Is Failing

Your car has about a million systems and sensors associated with and running its ten million processes—at least if you … Continued

Your car has about a million systems and sensors associated with and running its ten million processes—at least if you have anything manufactured between 1990 to today. And due to these parts’ fragile nature, wear, tear, and time can muck them up and cause them to fail. Of those sensors, the throttle position sensor is vitally important to your car’s continued functionality. 

Better understanding your car’s systems and sensors, including the throttle position sensor, will help you diagnose it when something fails or the car begins to malfunction. Allow Car Bibles’ editors to take you by the hand and walk you through exactly what a throttle position sensor is, what it does, and symptoms of its failure. 

What Is a Throttle Position Sensor?

A throttle position sensor is an electronic device that monitors the airflow coming into the engine as controlled by the throttle. 

How Does the Throttle Position Sensor Work?

Most throttle position sensors are located between the car’s air intake and throttle body. This placement allows the throttle position sensor to help the car’s electronic control unit (ECU) determine the correct air-to-fuel ratio as related to throttle input. 

Failing Throttle Position Sensor Symptoms

Here are some of the most common symptoms of a failing throttle position sensor.

Lacking Power

If your throttle position sensor is failing or has somehow tripped, your car’s ECU might limit the amount of power offered when you hit the gas pedal. 

Unintended Acceleration

A failing sensor could cause unintended acceleration, meaning your foot is off the accelerator pedal but the car still accelerates.

Unintended Stalling

Likewise, the car could stall due to a lack of power delivery when your foot is on the accelerator pedal. 

Check Engine Light

A check engine light is the most common and easily identifiable symptom. If you see it illuminated on your dashboard, you can plug in an OBDII scanner and determine the precise issue or verify it’s your throttle position sensor. 

Car Bible’s Glossary Related to Your Throttle Position Sensor

Welcome to Bible School!

Throttle

The throttle, also known as the gas pedal, is the right pedal in your footwell. It controls the power delivery of your car. 

Brake

Brakes are the friction devices used to halt your car’s momentum. Most modern cars use disc brakes that are actuated by the pedal directly to the left of your gas pedal.

Left-Foot Braking

Some cars can throw throttle position sensor codes and trigger the system if the driver uses the left foot to actuate the brake, i.e. any new Alfa Romeo. 

Your Questions, Our Answers on Throttle Position Sensors 

Car Bibles answers all your burning questions!

Q: What Happens If You Disconnect the Throttle Position Sensor?

A: Your car most likely won’t work. The throttle position sensor tells your car’s ECU the throttle input, and if that isn’t coming in, it will likely dole out limited power or no power at all. 

Q: Can I Clean the Throttle Position Sensor?

A: You can, though you’ll need to locate it first. You can thumb through your car’s dusty old manual to find its exact position. Once located, a little cleaning solution and a clean rag is all you’ll need. 

Q: What Is the Code for the Throttle Position Sensor?

A: P0122.

Q: How Much Does a Throttle Position Sensor Cost to Replace?

A: That’ll depend on your car’s make and model, but on average, throttle position sensor replacements cost between $170-$220 with parts and labor. 

Video on Throttle Position Sensor 

Car Bibles’ editors understand that not everyone is a text-based learner. For those kinesthetic people out there, we have your back with a video showing you exactly how throttle position sensors can fail and what to expect. We pulled it from one of our favorite, and most trusted, sources and it’s a great additional resource.

Car Bible’s Favorite Throttle Position Sensor Related Products

You can buy tools for diagnosing a faulty Throttle Position Sensor at almost every auto parts and home improvement store. As well as online stores like Amazon. You have a sea of options to select from. That’s why we’ve already put together a list of the best OBDII scanners available. You’re welcome. 

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Jonathon Klein

Jonathon KleinJonathon has jumped Aston Martins for Automobile Magazine, clocked 200 mph in a McLaren 720S for Playboy, and sampled his best life behind the wheel of a Ferrari Dino Evo for Road & Track. He’s hopelessly addicted to the strongest coffee he can brew. Please send him more. Contact the author here.