6 Signs of a Bad Accelerator Pedal Sensor (Replacement Cost)
In old cars, there was a cable between the throttle body and the accelerator pedal. Nowadays it is handled with electronics. Here’s how to tell if your accelerator pedal position sensor is bad.
- By Magnus Sellén
- Updated: July 26, 2022
Modern vehicles are equipped with many sensors and computers to automatically and precisely manage basic car controls.
They help to achieve better gas mileage and a smoother, comfortable, and safe drive.
Almost every modern car now has a sensor called the TPS and an accelerator pedal position sensor. As the name implies, these sensors are precision devices that determine the position of the accelerator pedal.
In this article, you will find the most common symptoms of a bad accelerator pedal position sensor, its location, and replacement cost. Let’s begin with a quick overview of the signs to look for:
Bad Accelerator Pedal Position Sensor Symptoms
The most common symptom of a bad accelerator pedal position sensor is an unresponsive accelerator pedal, often together with a check engine light on your dashboard. You may also notice symptoms like shifting issues, rough idle, or high fuel consumption.
A failing accelerator pedal sensor’s impact is pretty much obvious as it directly affects how the car drives and responds to the pedal and gas mileage.
If any of these symptoms occur or your car isn’t responding accurately when you press the gas pedal, you should pull over immediately and call a mechanic.
Here is a more detailed list of the most common symptoms of a bad accelerator pedal position sensor.
1. Your car hesitates to move when the gas pedal is pressed
This symptom is easy to detect as every owner eventually gets familiar with how their car responds to pressing the gas pedal. If you feel that your car is hesitating to move, your accelerator pedal sensor could be failing.
In such a case, it is advised to pull over immediately and call a mechanic since bad pedal timing can prove to be fatal.
2. Rough Idle
The optimal RPM of a car engine is around 600 to 700 rotations per minute. At these RPMs, the engine idles smoothly without shaking and consumes little fuel. If your car is unable to idle smoothly, a bad accelerator pedal sensor could be the reason besides the fuel mixture.
3. Your car doesn’t accelerate over a specific limit
If your car is only able to accelerate up to a point and won’t go faster beyond that speed, your accelerator pedal sensor is not able to send positioning signals accurately, which causes your car not to speed up beyond a point of pressing the gas pedal.
4. Your car won’t shift up or jerks upon depressing the pedal
If the accelerator pedal sensor isn’t working as it should, it will give out incorrect reading to the car’s automatic transmission computer. In such cases, because the sensor is bad.
Depressing it would sometimes give out delayed signals or a burst of varying signals, which your car’s computer tries to accumulate and use to adjust the mixture.
5. You experience low gas mileage
Your car’s throttle position sensor is often at its failing stage, but the effects aren’t obvious to you. You may not be noticing a delayed response from the pedal, but if you see low gas mileage, it could mean that the car’s throttle position sensor is working but not as accurate as it should be.
6. Check Engine Light
Modern cars have a monitoring system over all the sensors in the car engine. If the engine control unit suspects that one of these sensors is broken and sending out a wrong signal – it will light up the check engine light.
If your check engine light is on, you should definitely check the trouble codes with an automotive scan tool.
What is an Accelerator Pedal Position Sensor?
Modern cars do not have a wire between the accelerator and throttle body; instead, they use an electronic system.
A driver continually depresses the accelerator pedal giving it a varying amount of pressure, which determines how the car moves forward.
The TPS sensor and the accelerator pedal sensor tracks the gas pedal’s movement, which sends signals to the car’s computer. The computer then uses that information to adjust the air-fuel mixture and the throttle body valve according to the gas pedal position, current speed, the air temperature, MAF reading, and RPM. The result is a smooth and responsive drive.
Some cars use both an accelerator pedal position sensor on the pedal and one TPS sensor on the throttle body, while some cars only have a TPS sensor on the throttle body.
A TPS sensor’s importance can be emphasized as it can affect the gas mileage and engine response.
Accelerator Pedal Position Sensor Location
The accelerator pedal position sensor is located inside the accelerator pedal. In some cases, it is possible to replace just the sensor – but on other car models, you have to replace the whole accelerator pedal.
Removing the accelerator pedal can sometimes be challenging, but it is pretty straightforward on most car models.
Accelerator Pedal Position Sensor Replacement Cost
The average accelerator pedal sensor replacement cost is between $100 and $300, depending on the car model and labor costs. The accelerator pedal sensor usually costs between $50 and $200. The labor cost can range from $50 to $100 at a workshop.
The cost differs a lot depending on if you can replace just the position sensor or, like in some car models – you have to replace the whole accelerator pedal, which makes it much more expensive.
Remember that you sometimes have to calibrate the new accelerator pedal position sensor, which can only be done with a diagnostic tool.
How do I reset my accelerator pedal sensor?
How to reset the accelerator pedal position sensor depends on your car model. However, on most car models you will need to disconnect and reconnect the car battery. Then you turn on the ignition and fully depress the gas pedal, then release it. Then turn off the ignition again and after this the sensor should be calibrated.
How do I test the accelerator pedal position sensor?
The easiest way to test an accelerator pedal position sensor is to use a diagnostic computer. Read the voltage going through the position sensor and make sure it gives the correct values when you depress the accelerator pedal position sensor fully. The values are often shown as percentages.
Is a throttle position sensor the same as an accelerator pedal position sensor?
No, they are not the same. The throttle position sensor is located inside or on the throttle body of the engine. The accelerator pedal position sensor is located on the accelerator pedal inside the car.
Is it safe to drive with a bad accelerator pedal position sensor?
No, it is not safe to drive with a bad accelerator pedal position sensor. The pedal sensor sends information to the engine control module about how much you want to accelerate the engine, which then sends this information to the throttle. The last thing you want is for the ECM to send the wrong information about this.