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Summary
  • Diagnostic Trouble Code (DTC) P0123 code stands for “Throttle/Pedal Position Sensor ‘A’ Circuit High.”
  • The powertrain control module (PCM) will trigger the P0123 code if the throttle position sensor sends a signal that exceeds a certain threshold for a specific amount of time.
  • The P0123 code can be caused by a defective throttle position sensor or pedal position sensor, wiring issues, a dirty throttle body, or PCM issues.
  • The common symptoms of the P0123 code include an illuminated check engine light, hesitating during acceleration, or a rough-running engine.

The throttle position (TP) sensor is a device that helps the engine computer determine optimal ignition spark timing and fuel injection. It does this by determining how far open the throttle valve is. Vehicles with electronic throttle control (ETC) use two throttle position sensors as a fail-safe measure.

See also  Bad Throttle Position Sensor Symptoms: What You Need to Know

If the engine computer receives a signal from the TP sensor that exceeds the maximum limit for a set period, a P0123 code may get registered by on-board diagnostics.

throttle position sensor
Code P0123 may be triggered when your car computer receives a signal from the TP sensor that exceeds the maximum limit for a set period.

What Does the P0123 Code Mean?

Diagnostic Trouble Code (DTC) P0123 code stands for “Throttle/Pedal Position Sensor “A” Circuit High.”

The throttle position (TP) sensor “A” is a potentiometer that is mounted on the throttle body and shaft that determines the throttle valve position. It monitors the throttle blade angle and relays this information to the throttle actuator module or powertrain control module (PCM).

A signal that exceeds a certain threshold for a specific amount of time will cause the PCM to log a throttle position sensor code.

It’s worth noting that vehicles with ETC also use a pair of accelerator pedal position (APP) sensors to measure how far the gas pedal is being depressed. On some vehicles, code P0123 may also be set if there’s a problem with the APP sensor, rather than the TP sensor.

If you’re planning to resolve P0123 yourself, you can find more useful information in our technical discussion about throttle position sensors.

See also  P0332 Code: Knock Sensor 2 Circuit Low Input (Bank 2)

Note: The definition of code P0123 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

cleaning throttle body
A dirty throttle body is one of the possible causes of the P0123 code.

What are the Possible Causes of the P0123 Code?

What are the Common Symptoms of the P0123 Code?

How to Diagnose the P0123 Code

A DTC P0123 is a generic trouble code that may be logged in vehicles from different auto manufacturers. While these vehicles may exhibit similar triggers and symptoms, the steps for diagnosis and repair may vary between different makes and models.

If you’re not confident about conducting diagnostic tests on your vehicle, it’s a good idea to bring it to a professional mechanic. Otherwise, you may go ahead and diagnose the issue yourself. To help you get started, here are some videos that may give you an idea of what the process might involve:

See also  P0121 Code: Throttle/Pedal Position Sensor "A" Circuit Range/Performance Problem

How to Fix the P0123 Code

Attempting to fix a P0123 code may become a frustrating task if you don’t have the right tools and know-how to test the sensor circuit. In most cases, it’s best to leave the job to professionals.

For DIYers with advanced technical knowledge and hands-on experience who prefer to test and replace their TP sensor on their own, it will be helpful to rely on repair manuals. Guides like those from Chilton or an ALLDATA subscription provide vehicle-specific repair information.

Producrs Mentioned in this Guide

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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