10 Bad Throttle Position Sensor Symptoms & Replacement Cost

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bad throttle position sensor symptoms

Being in power or control of your surroundings is usually an awesome experience. It doesn’t matter whether you’re at work, or somewhere doing tasks, or driving your automobile. However, in contemporary automobiles, control doesn’t always depend on your hands or feet. In other instances, your vehicle’s computer relies on data from the numerous sensors and system components installed to monitor how your car is driven.

One such thing is your engine’s throttle position sensor (TPS). The TPS is a component of your automobile’s fuel management system. It assists in delivering the proper air/fuel mixture to your engine. The throttle position sensor gives the most immediate feedback to the fuel injection system of your engine’s power requirements.

The throttle position sensor signal is continuously monitored and merged with various data points such as engine RPM, air temperature, mass air flow, and the rate at which your throttle position moves. The acquired data is used to accurately calculate the amount of fuel to pump into your engine at any particular time.

When your throttle position sensor and its other accompanying sensors perform their functions properly, your automobile runs smoothly and accelerates efficiently as expected while preserving optimal fuel efficiency. In this article, we’ll explore the several symptoms of a failing throttle position sensor and other details regarding this vital part of your car’s engine. Read on to learn more!

Bad Throttle Position Sensor Symptoms

  • Weak Acceleration
  • Rough or Unstable Idle
  • Unusual Car Jerking
  • Poor Fuel Economy
  • Engine Stalling
  • Acceleration Changes
  • Gear Shifting Problems
  • Hard Starting
  • Car Enters Limp Mode
  • Check Engine Light

What Is A Throttle Position Sensor?

This component is precisely what the name says when you think about it. Throttle position sensors communicate the position of your throttle to your automobile’s computer. Essentially, it informs the engine control module (ECM) of the force with which you are pushing your accelerator pedal.

This enables your car’s computer to maintain an adequate air/fuel ratio. The greater force applied to the gas pedal, the more significant air and fuel must be supplied. If the position of your gas pedal is determined, your automobile could adjust how much air is entering your intake manifold using its mass airflow sensor.

Additionally, the fuel injection system of your vehicle understands just how much fuel to pump into your engine cylinders. Since these measurements are incorrect, everything begins to go poorly. In early automobiles, this was accomplished mechanically by a wire connecting the gas pedal to the throttle body or carburetor.

When the accelerator pedal is pushed, the butterfly valve within the body will release open, allowing extra air to enter the fuel system. But, this is accomplished electrically in today’s sophisticated automobiles. As a result, modern cars are significantly more economical.

How Does The Throttle Position Sensor Operate?

Any automobile equipped with an internal combustion engine features a throttle body, often known as the butterfly valve. This throttle valve is located between the engine’s intake manifold and air filter housing.

Your throttle position sensor’s function regulates the airflow entering your engine. As you hit your gas pedal, additional air is required in your engine’s internal combustion chamber. Additionally, extra fuel is pumped into your engine when more air reaches it. The ignition of this air/fuel mixture generates your engine’s power.

Your throttle position controls the proper amount of air that penetrates your engine. This position is detected by a component within your fuel management system termed the throttle position sensor or TPS. Its sensor transmits data about the throttle position to your engine control unit (ECU) whenever your car is accelerating.

Your ECU will then handle the throttle, allowing it to draw in whatever quantity of air your engine requires. The harder you press the accelerator pedal, the broader the throttle body opens, allowing increased airflow into your engine. Simultaneously, more fuel would be delivered into your engine cylinders to achieve a proper combustion ratio.

Bad Throttle Position Sensor Symptoms

So, how would you determine if you have a faulty throttle position sensor? There are various indicators to keep an eye out for. As you might think, most of them have to do with your engine idle and your vehicle’s acceleration.

If your car computer can’t detect the position of your throttle, this might have a significant detrimental influence on your engine’s efficiency. Once you detect any of the symptoms of a bad TPS listed below, you must get your automobile inspected immediately. Any bad throttle sensor might lead your vehicle to stall or accelerate unexpectedly, putting you in danger of crashing.

Weak Acceleration

Regardless of how hard you push the throttle pedal, your automobile would accelerate weakly, or worst, won’t accelerate at all. In uncommon instances, your vehicle could suddenly accelerate by itself, which could be very risky.

This situation is quite frightening for rookie automobile owners. However, your automobile won’t accelerate above 30 up to 50 kilometers per hour in most cases. To handle this, maintain your composure and shift to neutral. If you can’t do so, attempt to switch off your engine.

Whenever this occurs on a busy street, please activate your hazard lights. Additionally, avoid pulling the keys out since this may cause your steering wheel to lock. Bear in mind that incorrect driver input might also result in this condition.

Rough or Unstable Idle

Not merely could a defective throttle position sensor create issues during acceleration, yet it could also create difficulties when your vehicle is idling. Even if you don’t hit the throttle pedal during idle, your TPS sensor might continue to provide erroneous data.

Once your sensor malfunctions severely enough, your vehicle might not even start. This could cause your ignition timing to go wrong, resulting in misfiring and an exceedingly unpleasant ride.

Unusual Car Jerking

Once you detect your automobile jerking or bucking, immediately contact your trusted mechanic. This is frequently a sign of a bad throttle position sensor since your car is trying to accelerate by itself.

The surging sensation is caused by your sensor’s measurements not staying steady. As it begins to jump about, your automobile begins to accelerate or decelerate erratically. If this occurs, your vehicle could potentially stall. This isn’t acceptable and must be corrected immediately.

Poor Fuel Economy

This is a widespread indicator of a bad throttle position sensor. You might realize that you’re refueling up your vehicle more frequently than usual. This could be because your automobile is running too rich, consuming too much fuel than necessary.

When your throttle position sensor is defective and consistently reads excessively high, extra fuel is injected into your cylinders, resulting in waste. Decreased fuel economy might also indicate other issues, such as bad fuel injectors or faulty spark plugs; therefore, it’s advisable to get your automobile inspected by a mechanic to ascertain the root of the trouble.

Engine Stalling

Abnormal stalling is a telltale indicator that your car’s throttle position sensor is failing. While stalling could be a symptom of any underlying automotive issue, this might be the primary cause if it occurs often.

Therefore, don’t disregard the matter. Additionally, to prevent any serious issues on the road, equip yourself with some essential information and auto maintenance recommendations for your vehicle.

Acceleration Changes

Rapid acceleration without even pushing on the throttle pedal is a very peculiar acceleration issue that could occur. You could be traveling down the road when your automobile suddenly accelerates on its own.

Clearly, this could be pretty deadly. Among the several acceleration issues that might arise, this one is a dead giveaway that your throttle position sensor is the culprit.

Gear Shifting Problems

You might observe that your car’s automatic transmission isn’t shifting correctly, which may be a sign of a bad throttle position sensor. Automatic transmissions are incredibly complex, and your engine and its gearbox must function in unison when the vehicle changes gears.

If your engine RPMs don’t remain constant while switching gears, the shifts might be sluggish or seem to lag among gears. It would be best to examine this as soon as possible, as it might indicate transmission difficulties.

Hard Starting

Starting a vehicle with an internal combustion engine frequently needs more air and fuel than during idle or even running speed.

For that reason, one potential sign of a bad throttle position sensor is difficulties starting your automobile due to your engine not receiving the proper quantity of fuel. When the problem is severe enough, your automobile might not start at all.

Car Enters Limp Mode

Certain contemporary automobiles feature a specific limp mode that enables your car to operate at a minimal speed or performance once your engine has problems. This assists in preventing additional harm until the problem is solved.

Once your vehicle enters limp mode, it might result from a bad throttle position sensor. This is another indication that requires prompt attention since running your vehicle while on limp mode for a more extended period might be unsafe for you and those on your road.

Check Engine Light

Your throttle position sensor is a critical component of your internal combustion engine’s general operation. If your TPS fails, your engine would eventually be unable to create enough power to meet your acceleration requirements.

Once this issue occurs, your engine control unit will recognize it and illuminate your Check Engine light on your dash. This way, you’ll be informed that your engine suffers from an issue that requires attention.

How To Replace A Throttle Position Sensor

If you possess an acceptable level of automotive skills, you can replace your car’s TPS sensor on your own. However, if you have a minimum automotive skill but want to DIY the task, below is a list of step-by-step approaches that might help you replace your bad throttle position sensor. Let’s get it done!

Disconnect the Battery Cable

As you begin, detach the negative terminal connection from your battery. This would protect you from receiving undesired shocks and causing harm to other engine components.

Unplug the Faulty Sensor

After your sensor’s location has been identified, you must unplug the cable connection that links it to your engine’s software system. Unplug it gently to avoid damage to any clips or connections.

Disconnect Mounting Screws

After disconnecting your sensor, remove any screws that secure it in position. Maintain a record of everything in case they need to be reused to set up the new sensor.

Remove the Bad Sensor

Pull and dispose of your old broken sensor, discard it properly or keep it in case you need a sample in the future.

Install Your New Sensor

Reversing the procedure, screw in your new sensor into its correct position.

Re-Connect the Wiring Harness

Reconnect the wire harness to your new sensor gently and firmly, paying close attention to any snaps or connections that must be positioned for correct fitting.

Reattach your Battery Cables

Reconnect your negative battery cable to its terminal. Cheers! The task has been accomplished! Start your car, run it and observe.

Throttle Position Sensor Replacement Cost

The typical cost of replacing your throttle position sensor is around $80 up to $300, based on your vehicle type, labor expenses, and location. The throttle position sensor ranges in price from $30 up to $100. Labor expenditures for a session are typically around $50 to $200.

If your vehicle is equipped with an electronic throttle body, it’s likely that you can’t replace your throttle sensor alone; instead, you must replace your entire throttle body, which could run between $100 and $900.


Defective throttle position sensors might create chaos with your car’s functioning and could even make it hazardous to drive. Remember that a bad throttle sensor isn’t the sole source of these issues. Various components within your car that regulate air quantity and fuel injectors might exhibit similar problems.

This might be your MAF sensor or air filter. Therefore, carefully pay attention to such indications, as some of those might be possibly life-threatening. Once you see any of the signs and symptoms indicated above, schedule an appointment to get your automobile fixed soon!


What is the procedure for resetting a throttle position sensor?

Rebooting your throttle position sensor is as simple as disconnecting the engine control fuse for five minutes or disconnecting your negative battery connector.

Is it possible for a throttle position sensor to create gearbox issues?

Your throttle position sensor continuously analyzes its throttle position set mechanically through your throttle pedal. Your pedal is utilized to assess engine load, and failure to do so might result in a difficult-to-shift automatic transmission.

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