Symptoms of Bad Throttle Position Sensor | How to Reset Throttle Position Sensor

The throttle position sensor, also known as the TP sensor, is an integral component of your car’s fuel management system, playing a vital role in delivering the precise air-fuel mixture to the vehicle engine. By measuring the throttle valve position, the TPS helps in accurately calculating the ideal fuel delivery for the best engine performance. A bad throttle position sensor produces different signs. This article mainly explains the bad throttle body sensor symptoms, its causes, and how to reset it. 

What is a Throttle Position Sensor?

The throttle position sensor (TPS) is an electronic sensor used to measure the position of the throttle valve or throttle plate and transmits this information to the electronic control module (ECM).

It is usually mounted on the throttle body, which is the engine part responsible for regulating the amount of air entering the engine.

Throttle Position Sensor

The TPS calculates the position or angle of the throttle valve and sends this data to the engine control module (ECM). The ECM utilizes the information from the throttle sensor to measure the best suitable fuel injection rate and ignition timing for the best engine performance.

The throttle position sensor is operated through a potentiometer or a variable resistor that controls its electrical resistance according to the position of the throttle valve.

Symptoms of a Bad Throttle Position Sensor

 A bad throttle position sensor produces one or more of the following symptoms:

  • Poor Acceleration
  • Check Engine Light
  • Idle Surging
  • Sudden Surge while Driving at a High Speed
  • Misfires
  • Gear Shifting Issues
  • Poor Fuel Economy

1) Poor Acceleration

A sluggish or poor acceleration is one of the clear symptoms of a bad throttle position sensor. Poor acceleration is where there is a notable time gap between pressing the accelerator pedal and the actual increase in speed.

Poor Acceleration

Additionally, if your vehicle judders or experiences jerky movements during acceleration, it may also indicate a problem with the TPS.

2) Check Engine Light

When a vehicle’s sensors malfunction, the check engine light is typically triggered as a warning indicator. While there are multiple causes of the check engine light illumination, it is prudent to investigate the throttle position sensor if you experience symptoms such as idle surging and poor acceleration.

Check engine light

If the illuminated check engine light is specifically associated with the throttle sensor, it usually corresponds to an error code stored in the engine control module (ECM). To retrieve this code, an OBD-II scanner can be utilized for diagnosis.

Read More: How to reset Check Engine Light

3) Idle Surging

Another clear sign of a defective throttle position sensor is engine fluctuation while idling, causing an irregular air/fuel mixture. The idling indicates the engine operation when the car is not actually moving.

Engine Idle, symptoms of bad throttle body sensor

When the engine control module (ECM) receives inaccurate data from the faulty throttle sensor, it can result in erratic idle surges as the throttle fails to operate efficiently.

4) Sudden Surge while Driving at a High Speed

sudden surge

In the case of an electric throttle body, a faulty TPS may lead to a potentially hazardous situation: an abrupt increase in speed while driving at high speeds on the road. This occurs when the throttle valve of your vehicle unexpectedly closes, and if you press the accelerator pedal firmly, the valve abruptly reopens, providing a brief surge in speed.

Such incidents arise from a damaged throttle position sensor transmitting wrong signals to the throttle valve, leading to sudden and unexpected changes in its position.

5) Misfires

The engine misfiring or stalling while the vehicle is stationary is one of the clear symptoms of a faulty throttle position sensor (TPS). It’s crucial not to delay getting it checked by a professional.

Engine Misfiring

When the TPS malfunctions, the ECM of your car may struggle to detect when the throttle is fully closed, resulting in abnormal idling and potential engine stalls.

Read More: Engine Misfiring Symptoms and Causes

6) Gear Shifting Issues

A faulty TPS can disrupt acceleration, which, in turn, affects the performance of the automatic transmission.

Gear Shifting issues, signs of bad throttle position sensor

In addition to its impact on engine operation, the throttle position sensor also communicates vital data to the automatic transmission control unit. If this data is compromised due to a bad sensor, it can lead to shifting problems with your automatic transmission.

7) Poor Fuel Economy

A contaminated or faulty throttle sensor can provide inaccurate information to the ECM, causing the engine to consume more fuel than necessary. Consequently, this reduces your car’s overall fuel efficiency.

Poor Fuel Economy

Similarly, if debris accumulates around the throttle opening, obstructing airflow, unburned fuel may pass through the exhaust system, leading to performance issues and reduced fuel efficiency.

Causes of a Bad Throttle Position Sensor

  • Wear and Tear
  • Contaminants on the throttle position sensor
  • Damaged wiring or loose connections in the electrical circuitry of the throttle position sensor may disturb its function.
  • Exposure to extreme conditions
  • Manufacturer defects

Throttle Position Sensor Location

The throttle position sensor is typically located on the throttle body itself, as its primary function is to measure the angle or position of the throttle valve.

Throttle Position Sensor Location

To find the throttle position sensor, you can look for a sensor positioned parallel to the axle of the throttle body, with wires connected to it. This configuration is a strong indication that you have located the throttle sensor.

In modern vehicles equipped with electric throttle bodies, the throttle position sensor is commonly installed into the throttle body assembly. Consequently, it cannot be replaced as a separate component, and the entire throttle body unit will require to be replaced if your sensor becomes faulty.

How to Reset a Throttle Position Sensor

Follow one of the below-given methods to reset your throttle position sensor:

1) Use an OBD2 Scanner

One of the most famous methods to reset and calibrate a throttle position sensor in the latest vehicles is by utilizing an OBD-II scan tool. But it is crucial to ensure that the scan tool you purchase must be compatible with your specific car engine and has the necessary throttle sensor reset feature for your particular vehicle.

Thorough research should be conducted before making a buying decision to avoid compatibility issues. It is worth noting that for certain cars, a manual throttle sensor reset may be the only option available.

2) Remove the Fuse

The throttle sensor, being an electronic component of your car, can be manually reset by manipulating the corresponding fuse. To perform this reset, locate the fuse box, which is typically detailed in the vehicle’s manual. Identify the specific fuse associated with the throttle sensor.

Carefully remove the fuse and allow it to remain out of the fuse box for a duration of 8-10 minutes. After the allotted time, reinsert the fuse back into its original position. It’s important to note that while this resets the throttle body sensor, it will also reset any other system or component connected to that particular fuse.

3) Push Accelerator

In some cases, resetting the sensor can be a straightforward process. To begin, switch on your car without starting the engine and leave the ignition key in the ON position.

To initiate the keyless start system, simply press the button once without cranking the engine. Next, press and hold the accelerator pedal for approximately 20 seconds, ensuring that you push it as close to the floor as possible. Gradually release the pedal and proceed to switch off the vehicle.

Finally, turn on the engine using the usual method and take the car for a drive to check the engine performance.

4) Drive the Vehicle

In certain conditions, resetting the sensor may require driving the car. Turn on your car’s engine and drive for a few minutes, maintaining speeds above 40 mph constantly.

While driving, gradually accelerate and decelerate in small increments, allowing a few minutes between each session. This process can help to reset your sensor, resulting in improved performance.

5) Disconnect Battery

To reset an electronic component, one common approach is to disconnect the battery.

  • Begin by disconnecting the negative terminal of your vehicle’s battery.
  • It is recommended to wait approximately 5 minutes before rewiring the terminal.
  • It is important to note that disconnecting the battery will reset all electrical systems in the vehicle, including the stereo presets and clock. Therefore, most owners prefer to explore alternative approaches before resorting to this step.

6) Drain Vehicle Power

Keep in mind that even after disconnecting the battery, certain components in your vehicle may hold power. If other methods have been ineffective, draining power from all parts of the vehicle becomes necessary to reset the sensor.

  • To perform a thorough power drain, disconnect both the negative and positive cables from the battery.
  • After disconnecting the battery cables, sit in the vehicle and switch on the ignition switch while simultaneously pressing the brake pedal.
  • It is advisable to wait for approximately 8 to 32 minutes during this method to ensure complete power drainage from the car.
  • After waiting a few minutes, connect the battery cables again and start your engine. Your throttle sensor must be successfully reset.

7) Idle Engine

To reset your throttle position sensor, start by cranking the engine and allowing the car to idle for about 4 minutes. After 4 minutes, switch off the vehicle.

Repeat these steps once more. It’s worth noting that in certain car models, you may achieve the same results by turning the key to the ON position without starting the engine.

Consult the service manual specific to your vehicle to determine the ideal method for your vehicle model.

Throttle Position Sensor Replacement Cost

The throttle sensor replacement cost depends on the labor cost and the vehicle model. The average throttle position sensor replacement cost is from $60 to $330. A throttle sensor costs between $40 and $130. The labor costs are usually between $20 and $200.

FAQ Section

How to Fix Throttle Position Sensor?

For safety and to ensure the ECM is offline during the process, begin by disconnecting the negative terminal of the battery. This not only prevents electric shocks but also keeps the ECM offline. Allow a five-minute interval to reset your throttle position sensor. Alternatively, you can remove the ECM fuse for approximately five minutes to reset the sensor. After the reset period, your sensor should work fine after reconnecting all parts.

Can a bad throttle body sensor cause transmission problems?

In vehicles with an automatic transmission, multiple sensors play a role in determining gear shifts while driving. One of these sensors is the throttle position sensor, which communicates to the ECM when the accelerator pedal is utilized, regulating the air and fuel supply to the engine. Additionally, the throttle sensor informs the transmission when it is necessary to change gears. Consequently, a bad throttle position sensor may lead to transmission-related issues.

Can I replace my Throttle Position Sensor on my own?

Replacing the throttle position sensor is a task that is typically best left to a professional mechanic unless you possess sufficient mechanical knowledge and experience. It is worth noting that a throttle position sensor replacement may sometimes require additional repairs, such as inspecting or replacing the fuel tank. This complexity makes it challenging to perform the replacement as a DIY project.

Can I drive with a bad throttle position sensor?

While it is technically possible to drive with a faulty throttle position sensor, but it is strongly discouraged to do so. The throttle sensor plays a crucial role in measuring the airflow entering the engine. If the sensor malfunctions, it can negatively impact the performance of various engine components. Driving with a faulty throttle position sensor puts you and road passengers at risk of accidents due to compromised engine performance.

Can a bad throttle position sensor prevent the car from starting?

A defective throttle sensor can indeed prevent a car from starting. When the throttle position sensor is faulty, it can lead to improper functioning of the throttle body. This can manifest in two ways: either the throttle body fails to close properly, or it remains stuck in the closed position, inhibiting the normal starting process of the engine.

What controls the throttle position sensor?

In the engine of a vehicle, there exists a throttle valve that opens as you press the accelerator pedal. The purpose of a throttle position sensor is to gauge the degree to which the throttle valve is open, thereby regulating the amount of airflow entering the intake manifold of the engine.

Can the throttle position sensor cause a misfire?

When the throttle position sensor begins to deteriorate, it can manifest in various warning signs. These include rough idling, stalling, or engine misfires when the vehicle is stationary.

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