What is an Accelerator Pedal Position Sensor?
The accelerator pedal position (APP) sensor system provides information to the powertrain control module (PCM) about the position of the accelerator pedal and the speed and pressure of the accelerator pedal. It is also known as a ‘drive-by wire’ system.
In simple words, the accelerator pedal sensor informs your throttle body how far to open. The accelerator pedal position sensor is located near the accelerator pedal. It informs the PCM how hard the accelerator pedal is pushed.
As the driver presses or lets off the gas pedal, the accelerator sensor gets that data and delivers it to your car’s PCM.
The accelerator pedal sensor and the throttle position sensor observe the motion of the accelerator pedal and send a signal to the PCM. The PCM then uses this information to regulate the fuel-air mixture and throttle valves based on accelerator pedal position, RPM, temperature, MAF sensor reading, and current speed.
Some vehicle models contain the accelerator sensor in the pedal and the throttle position sensor in the throttle body, while few models only contain the throttle position sensor in the throttle body.
The importance of the throttle position sensor can be stressed as it affects fuel economy and engine performance.
How does Accelerator Pedal Position Sensor Work?
The accelerator pedal position sensor uses a Hall Effect sensor that uses a magnetic field to measure the position of the pedal. It generates a variation in the charge based on changes in pedal position.
The gas pedal of your vehicle is linked to a throttle body that controls the air flow entering the engine. A servo motor is used to control the throttle body. An accelerator pedal sensor uses to drive this motor.
As the driver presses or lets off the gas pedal, the accelerator sensor sends a signal to PCM, which tells how far the accelerator has depressed. The PCM then uses this information to regulate the fuel-air mixture and controls the servo motors accordingly.
When the accelerator sensor goes bad, your vehicle may face different drivability issues, such as poor acceleration, poor fuel economy, check engine light illumination, and engine stalling.
Accelerator pedal sensors have a simple design and generally do not fail on their own. Most often, these sensors may fail due to impurities. Water and dirt getting into the sensor may cause it to fail over time. The simplest method to fix a bad accelerator pedal sensor is to replace it.
Symptoms Of a Bad Accelerator Pedal Position Sensor
The efficient working of the accelerator pedal sensor is very important for the optimum performance of the engine. When the accelerator pedal position sensor goes bad, it produces one or more of the below-given symptoms:
- Car hesitates to move when the gas pedal is pressed
- Check engine light illumination
- Acceleration problems
- Shifting problems
- A reduction in engine power
- Rough idling
- Poor fuel economy
1) Car hesitates to move when the gas pedal is pressed
One of the most common symptoms of a bad accelerator pedal position sensor is car acceleration problems. Your accelerator sensors are responsible for ensuring the proper acceleration of your vehicle.
If your vehicle is not running properly, you should stop it and immediately contact a professional to fix the problem.
2) Check Engine Light Illumination
The check engine light illumination is a clear symptom of a bad accelerator sensor. The accelerator pedal position sensor is an electrical element. This sensor sends information to the PCM, and if something goes bad, it triggers an error code. You may notice a logged error when the check engine light comes on.
In order for a PCM to function properly, all of the car’s electronic sensors must function properly. A faulty accelerator sensor will log a P2135 diagnostic trouble code.
There are many other causes of the check engine light illumination. Therefore, you may need a certified mechanic to diagnose the true cause of the code.
3) Acceleration Problems
As the driver presses the accelerator pedal and the vehicle engine must respond instantly. However, when the accelerator pedal sensor goes bad, the vehicle’s capability to decelerate or accelerate immediately after the driver presses the accelerator pedal will be greatly reduced. This may create hazards on the road as the driver doesn’t have full control of the car.
If you are driving on the road and your car suddenly stops moving, this situation is very hazardous and may cause an accident.
If you observe uneven acceleration, you should stop driving. If you experience uneven acceleration, ensure the vehicle is parked safely and immediately contact your professional technician to diagnose and fix the issue.
4) Shifting Problems
The shifting problem is one of the clear symptoms of a bad accelerator pedal position sensor.
When the gas pedal sensor doesn’t work efficiently, it sends the wrong information to the powertrain control module (PCM). In such conditions, as you press the gas pedal, you may face shifting or parking problems.
5) A reduction in Engine Power
A faulty accelerator pedal position sensor may lead to poor engine performance. Fuel economy can also be an issue if the APP sensor is not working properly. It not only monitors throttle pressure and applies it to the throttle body but also assists in stabilizing throttle control.
This sensor stabilizes fuel pressure while also delivering data from the PCM to the vehicle’s throttle body. If the sensor isn’t properly transmitting this data to the PCM due to damaged, frayed, or corroded wiring, you’ll see a significant reduction in engine performance.
6) Rough Idling
A bad accelerator sensor may lead to rough idling. A good working accelerator sensor ensures the proper supply of fuel and smooth idling. As the sensor goes bad, it doesn’t properly supply fuel, leading to rough idling.
Read More: Why Car Shakes at Idle?
7) Poor Fuel Economy
Poor fuel economy is one of the common symptoms of a bad acceleration pedal sensor. However, there are many other causes of poor fuel economy, such as a bad throttle position sensor or a dirty throttle body.
Read More: How to Clean a Dirty Throttle Body
Causes of a bad Accelerator Pedal Sensor
- Damaged or corroded wiring of the accelerator sensor
- Bad or faulty sensor
- Contamination inside the accelerator sensor
- A bad connection between the PCM and the sensor
Accelerator Pedal Position Sensor Location
The accelerator pedal position sensor is most commonly located within the accelerator pedal. In the case of some vehicle models, when your sensor goes bad, you need to replace it, but in the case of some vehicles, it is necessary to replace the entire accelerator pedal.
Replacing the accelerator pedal may be tricky, but it’s easy on most models.
How to fix bad Accelerator Pedal Sensor
Follow the below-given steps to replace a faulty accelerator pedal sensor:
1) Disconnect the negative battery terminal
First of all, disconnect the negative battery terminal before working on the electrical parts. This prevents you from electrical shock and damage to other electrical parts.
2) Remove the old APP sensor
Find the accelerator pedal sensor and remove the wire harness that transfers the electrical signal to the PCM. Press the knob and unplug the sensor.
3) Remove installation screws
After disconnecting the wiring harness, remove the mounting screw that secures the sensor. If you plan to reuse the screws to reinstall the new sensors, keep them in a safe location.
4) Remove the old APP sensor
Carefully remove the old sensor and inspect it properly. Be careful not to interfere with local rules.
5) Compare both Sensors
We recommend that you compare the old and new sensors before installing the new ones. This is vital when replacing components with aftermarket parts. Don’t forget to test the new sensor before installing it.
6) Install the new accelerator pedal sensor
Reverse the steps to install the new sensor in the place where you removed the faulty sensor.
7) Re-plug the electrical connectors
Carefully re-plug the electrical connectors back into the new accelerator sensor. Perform a proper inspection of the connectors and align them for proper installation.
8) Reconnect the negative battery terminal
Connect the negative cable back into the battery and tighten it with a fairly large wrench set. Now perform a test drive of your vehicle.
How to Replace an Accelerator Pedal Position Sensor
Accelerator Pedal Position Sensor Replacement Cost
The replacement cost of the accelerator pedal sensor varies according to your living area and vehicle model.
The average replacement cost of the accelerator pedal sensor is from $80 to $320. In this cost, the accelerator pedal sensor usually costs from $40 to $210, while the labor cost is from $40 to $110.
What happens when the accelerator pedal position sensor fails?
When your accelerator pedal sensor goes bad, it produces one of the below-given symptoms:
Can you drive with a bad accelerator pedal position sensor?
Yes, you can drive with a bad accelerator pedal position sensor, but it is not recommended. Driving with a bad accelerator sensor may lead to different drivability issues, such as poor acceleration or engine stalling. When the sensor goes bad completely, the car may go into limp mode. When your car goes into limp mode, it moves at a very low speed. Now you can return home safely without damaging your car. The sensor can degrade over time and fail.
How do I reset my accelerator pedal sensor?
The method to reset the accelerator pedal position sensor varies according to your vehicle model. Follow the below-given steps to reset the accelerator pedal sensor:
- Disconnect the battery and reconnect it after a few minutes.
- Turn on the ignition switch and fully press and release the accelerator pedal.
- Now turn the ignition switch off again and calibrate the sensor.
Is it safe to drive with a bad accelerator pedal position sensor?
It is very dangerous to drive with a faulty accelerator pedal sensor. This sensor notices the acceleration pedal position and transfers this data to the PCM. The PCM sends this data to the throttle body. A faulty sensor sends wrong information to the PCM, which may lead to various drivability issues.
What is the most common cause of a stuck accelerator?
The following are the major causes of stuck acceleration:
- The components in the engine-management system
- Damaged accelerator links
- Faulty vacuum hose
How long should an accelerator last?
The service life of your vehicle accelerator depends on its maintenance. The average service life of the accelerator is from 2 months to 6 months. The aim is to prepare the company to act independently and build a strong position to gain a foothold in the target market.
What would make a car struggle to accelerate?
Poor acceleration is caused by a clogged fuel injector, insufficient fuel supply, or insufficient fuel pressure. Clogged fuel injectors may lead to poor vehicle performance, slow vehicle acceleration, and a feeling of being underpowered.