Bad Throttle Position Sensor Causes & Symptoms

You and your vehicle have traveled many miles together. She’s always run smoothly and gotten where you need to go safely. That is, until now. Over the past few weeks, you’ve noticed that something’s not quite right. Could it be your throttle position sensor?

In this guide, we’ll take a look at bad throttle position sensor causes and symptoms. How do you know when you should visit a mechanic? What are the signs that you may be having TPS issues? 

What is a Throttle Position Sensor?

Before we dive into potential problems with your throttle position sensor, let’s get a clearer picture of what this engine component does. 

Put simply, the throttle position sensor is exactly what its name implies. It’s a sensor that relays information to your engine about where your throttle (your gas pedal in most cases) is positioned. 

Your TPS monitors the air intake of your vehicle, ensuring that the right combination of air and fuel is in your engine. The computers in your car communicate with your engine control module to determine just how much fuel should be delivered at any point in time.   

In other words, it’s literally the job of the throttle position sensor to ensure that your car runs smoothly.

Bad Throttle Position Sensor Symptoms

There are several “symptoms” that your throttle position sensor is going bad, and they’re relatively easy to spot. These symptoms can be intermittent, only occurring every few times you drive your vehicle. However, it’s important not to ignore the signs of a bad throttle position sensor, as doing so could leave you stranded on the highway. 

Your Vehicle Is Slow To Accelerate

Imagine you’re driving up the onramp to the freeway. Your vehicle will accelerate, but you can’t seem to get the car past a certain speed. This could be a sign of a bad throttle position sensor. 

Your Car Isn’t Smoothly Idling

When you’re idling at a stoplight and your engine speed is uneven, that could be a sign that your TPS is failing. 

Too Little Or Too Much Power

Your throttle position sensor indicates how much fuel should be sent to your engine. If your TPS is beginning to fail, you may notice changes in the power of your vehicle. For instance, you may be trying to accelerate but can’t. Conversely, you may be driving at a steady pace and your car suddenly lurches forward. Both are signs that your throttle position sensor is failing. 

Sudden, Drastic Changes In Fuel Efficiency

If you’ve noticed that you’re filling up your tank more frequently lately, that could be a bad throttle position sensor symptom. While anything from spark plugs to underinflated tires can impact your fuel economy, it’s worth a look. When lowered fuel efficiency happens in conjunction with other symptoms, your TPS may be to blame. 

Bad Throttle Position Sensor Causes

As is the case with just about everything, your car will age. Your throttle position sensor is just one component of your vehicle, and it’s possible that it’s simply time to have some maintenance done on your TPS. 

There are other bad throttle position sensor causes, though. Faulty wiring can cause your TPS to behave poorly. A short in your electrical system can, as well. Even vibration caused by a vehicle that needs alignment can affect your throttle position sensor and cause it to fail. 

The truth of the matter, however, is that it’s uncommon for a TPS to go bad. If you feel that your throttle position sensor is the cause of your car’s malfunction, it’s best to take your vehicle in for service. A larger, underlying issue could be present, and you’ll want to get it fixed as soon as possible. 

Repair costs for a bad throttle position sensor will vary, but the price is most directly related to how accessible your TPS is. If your sensor is conveniently located and accessible, you can expect the repairs to cost as little as a few hundred dollars, including labor. If it’s necessary for a mechanic to disassemble parts of your car to access the TPS, your estimate may be more likely in the thousands. 

Conclusion: Bad Throttle Position Sensor Fails

Bad throttle position sensor causes and symptoms are relatively cheap to fix and also fairly easy to diagnose. If you notice any of the symptoms of a bad TPS as you drive, bring your car to a technician right away. Failure to fix your TPS sooner than later can lead to much bigger problems down the road.