Throttle/Accelerator Pedal Position Sensor
Accelerator Pedal Position Sensor
The accelerator pedal position (APP) sensor allows smooth acceleration while utilizing minimal energy. The APP sensor on the ‘electronic throttle control system with intelligence’ (ETCSi) detects the pedal position. The AAP sensor also converts pedal movement into an electronic signal that opens or closes the throttle body.
The accelerator location data is sent to the TAC and PCM modules (PCM). The accelerator position sensor is made up of two separate sensors, each with its own sensor return wiring. Each sensor’s voltage range varies.
The PCM system receives and interprets inputs from the ACC sensors, as well as the DC motor that adjusts the throttle plate through a throttle cable. When the driver depresses the accelerator pedal, it rotates the throttle plate inside the throttle body, allowing airflow. The airflow sensors activate the engine control unit and force gasoline into the fluid injector system as it passes through the throttle path.
The APP sensor system gives information to the engine control module systems regarding the accelerator pedal position, pressure, and speed. As shown in the video below, the APP sensor is linked to various automated actions, one of which is reverse. In reverse, the PCM modifies the vehicle’s acceleration pattern.
The APP sensor unit contains a potentiometer (mounted on the accelerator pedal). In some sensors, the APP sensor unit consists of two or three sensors. In a hierarchical system, the first sensor is the main input. If the output voltage signal from the potentiometers monitoring the pedal position or the sensor itself differs, the PCM unit will lower the vehicle’s performance, putting the APP unit in ‘limp-home mode’.
The potentiometers generate distinct signals. To help ensure that the PCM unit is aware of the pedal position, the second and third sensors act as backup units. During vehicle movement, the PCM unit continually compares the output of all three APP sensor potentiometers.
Due to its location on the floorboard, near to the car firewall, the APP sensor is frequently damaged by excessive heat. Although APP sensors usually last the life of the vehicle, they may need to be updated. Resistive, magnetic, and inductive sensors have been found to have similar features and functions.
Throttle Position Sensor
The APP and TPS sensors have the same electrical circuitry. This sensor, like the APP sensor, is located on the throttle body and translates the throttle body butterfly valve angle into a voltage signal for the PCM. The TPS monitors whether the throttle valve or blade is open, which is indicated by how far the accelerator pedal is pressed.
The TBS also controls how much air enters an engine. For example, an open intake manifold allows more air into the system than a closed intake manifold. The engine control unit uses a voltage signal from the TPS to identify the throttle valve position and regulate the air-fuel ratio. The TPS unit, like the APP unit, has three wire-like components.
The TPS circuitry receives 5 volts from the PCM unit. The signal provided to the TPS during vehicle movement is 3.5–4.7 volts, indicating that the throttle valve is open.
This signal signifies that the driver has removed their foot from the pedal device, indicating a closed-throttle position switch.
Is there a difference between a throttle position sensor and a pedal position sensor?
Both the APP and TPS sensors have the same electrical architecture. The TPS sensor unit is located on the throttle body, same like the APP sensor, and translates the throttle body butterfly valve angle position into a voltage signal that is sent to the PCM unit. To identify the throttle valve position and allow for air-fuel ratio adjustment and fuel cut control, the engine control unit receives information from the TPS in the form of a voltage signal from the TPS.
Is it possible to drive without TPS?
The TPS, or Throttle Position Sensor, informs the ECU about how wide the throttle is opened and consequently how much gasoline is required. Without a TPS, you will be able to drive, but not very efficiently. When you open the throttle, the ECU detects a lean situation in the o2 and attempts to richen it up.
Symptoms of a faulty or failed throttle position sensor include:
1. Car won’t accelerate, doesn’t have enough power to accelerate, or accelerates by itself
It may appear that the vehicle is not accelerating as quickly as it should. It has a nice acceleration but lacks power. On the other hand, even if you haven’t hit the accelerator, your automobile may abruptly accelerate while you’re driving. If you experience these symptoms, there’s a good likelihood you’re dealing with a TPS issue.
2. The engine won’t idle smoothly, or it will idle too slowly, or it will stall.
When the car is stopped and you start to notice engine misfires, stalling, or harsh idling, it could be an indication of a failing TPS. You don’t want to put off getting this looked out any longer!
3. The car accelerates but does not exceed a low speed or shift up.
This is another TPS failure mode, indicating that the TPS is incorrectly restricting the power requested with your accelerator pedal foot. Your car may accelerate, but only to a top speed of 20 to 30 miles per hour. This symptom frequently occurs in conjunction with loss-of-power behavior.
4. The Check Engine Light illuminates, accompanied by any of the aforementioned symptoms.
If your TPS is malfunctioning, the Check Engine Light may illuminate. However, this isn’t always the case, so don’t wait until the Check Engine Light comes on to get it looked out. If you’re experiencing any of the symptoms listed above, get your vehicle’s trouble codes evaluated to determine the source of the problem.
How do I go about relearning the throttle body?
Some vehicles may require a throttle/idle relearn after the throttle body has been cleaned. Throttle retraining can also be accomplished without the use of a scan tool, by just allowing the vehicle to idle in park for several minutes while the ECM learns.
1. Turn on the engine and let it idle for three minutes in park. The idle may be higher than usual during that time.
2) Turn off the engine after 3 minutes and wait 60 seconds before starting it again.
3) Restart the engine and let it idle for another three minutes in park.
Sensor for throttle position and Accelerator Position Sensor:
TPS and APS are sensors that monitor an engine’s air intake. The sensor is commonly mounted on the butterfly spindle/shaft, allowing it to monitor the throttle position directly.
How do you use a multimeter to test a throttle position sensor?
Connect the multimeter’s negative probe to the TPS’s negative wire tab and the positive probe to the positive tab. If the TPS is working properly, the multimeter will read around 5 volts. Check the voltage of the signal. The positive probe should be connected to the signal wire tab, and the ground probe should be connected to the car’s frame.
14 DTC OBD Codes Related to APS and TPS Problem
- P0229 Throttle/Petal Position Sensor/Switch C Circuit Intermittent
- P0228 Throttle/Petal Position Sensor/Switch C Circuit High Input
- P0227 Throttle/Petal Position Sensor/Switch C Circuit Low Input
- P0226 Throttle/Petal Position Sensor/Switch C Circuit Range/Performance Problem
- P0225 Throttle/Petal Position Sensor/Switch C Circuit Malfunction
- P0224 Throttle/Petal Position Sensor/Switch B Circuit Intermittent
- P0223 Throttle/Petal Position Sensor/Switch B Circuit High Input
- P0222 Throttle/Petal Position Sensor/Switch B Circuit Low Input
- P0221 Throttle/Petal Position Sensor/Switch B Circuit Range/Performance Problem
- P0220 Throttle/Petal Position Sensor/Switch B Circuit Malfunction
- P0124 Throttle/Petal Position Sensor/Switch A Circuit Intermittent
- P0123 Throttle/Petal Position Sensor/Switch A Circuit High Input
- P0122 Throttle/Petal Position Sensor/Switch A Circuit Low Input
- P0121 Throttle/Petal Position Sensor/Switch A Circuit Range/Performance Problem
TOP 3 Common APS and TPS OBD DTC Codes
P0121 – Throttle/Pedal Position Sensor A Circuit Range/Performance
P0122 – Throttle/Pedal Position Sensor A Circuit Low
P0123 – Throttle/Pedal Position Sensor A Circuit High
Thank you very much! This tutorial is humbly made and researched by Erwin Salarda.