A: The throttle position sensor is usually on the throttle valve spindle where it monitors throttle angle, speed of throttle opening and closing, and closed throttle position at idle.
The throttle position sensor is in the throttle body assembly. In many cases, two throttle position sensors are used to provide accurate signals to the powertrain control module (PCM).
In an electronic throttle control (ETC) system, which is the most prevalent type of throttle control on todays’ vehicles, there are basically two types of TP sensors: potentiometer and Hall-effect. The potentiometer is a three-terminal resistor where a wiper contact delivers a variable voltage output, while the Hall-effect sensor monitors the magnetic field around wires with an electrical current.
Throttle position sensors and accelerator position sensors on ETC systems are always redundant, with two or three sensors in both places reading the same position but on slightly different scales that must agree with one another. This is to prevent uncontrolled acceleration due to the failure of one or more sensors. The ECM/PCM algorithms are written with potential sensor failure in mind.
Throttle position sensors and accelerator position sensors on ETC systems are always redundant, with two or three sensors in both places reading the same position but on slightly different scales that must agree with one another.
– Richard McCuistian, ASE Certified Master Automobile Technician
Some shop manual procedures say to disconnect the negative battery terminal before doing anything with the TP sensor, but there are many other manuals that never mention disconnecting the battery for TP sensor service. Most professionals won’t disconnect the battery for this because the TP sensor only operates on 5 volts anyway and very little current.
To access the sensors, disconnect the sensor connector (look for the tab or tabs to squeeze and release). You can then unscrew the sensor from its mounting point. Be aware that the TP sensor screws probably have thread locking compounds on them and the screws might be very difficult to remove. Typically, they’ll be a Torx type head or Posidriv, which looks like a Phillips head but is slightly different. New TP sensors usually come with new screws.
Keep in mind that these tips are generic steps for removing the throttle position sensor. It’s always a good idea to have a vehicle-specific repair guide or manual when working on repair and replacement tasks.
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