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Summary
  • DTC P2135 stands for “Throttle/Pedal Position Sensor/ Switch A/B Voltage Correlation.”
  • This code triggers when the PCM detects a problem with your vehicle’s throttle or pedal position sensors/switches.
  • Common symptoms include your vehicle entering Reduced Power Mode, decreased engine performance, and a lit check engine light.

You’re stopped at a stoplight, waiting for the light to turn green. Once the light changes, you suddenly notice that no matter how hard you step on the gas, engine power is significantly reduced. 

After you limp the vehicle home, you plug in your diagnostic tool and it reads P2135. What does this code mean and why are you experiencing these problems? 

Read on to find out.

replacement throttle position sensor
The throttle position sensor is located on the throttle body and once it fails, code P2135 may get triggered.

What Does the P2135 Code Mean?

Diagnostic trouble code (DTC) P2135 stands for “Throttle/Pedal Position Sensor/ Switch A/B Voltage Correlation.” This code appears when your car’s primary computer, which is often referred to as the powertrain control module (PCM), detects a problem with one of throttle and/or the pedal position sensors/switches. In most cases, the ECM will also force the vehicle into Reduced Power Mode.

How Code P2135 is Set

On an Electronic Throttle Control (ETC) system, the PCM keeps track of throttle plate position and uses input from two or in rare cases, three throttle position (TP) sensors mounted on the throttle body and a pair of accelerator pedal position (APP) sensors connected to the accelerator pedal.

Think of this as “throttle by wire,” because there’s always an electronic module receiving input from the APP sensors, driving the motor that opens the throttle plate, and reading throttle plate position from the throttle position sensors.

Redundant sensors are used on the accelerator pedal AND the throttle body as a solidly dependable way of detecting faults by comparing the sensor inputs to each other in real time.

See also  P0124 Code: Throttle / Pedal Position Sensor “A” Intermittent

And remember, unlike the redundant circuits and hydraulics in military aircraft, these sensors don’t come in pairs, so one sensor will still work if the other one fails. If one sensor fails the algorithms in the PCM or module are written to prevent accidents due to uncontrolled throttle events.

If one sensor doesn’t work or doesn’t agree with the other sensor as it should, fail-safe mode kicks in, reducing or eliminating throttle response for safety purposes. In some cases, the vehicle will only idle or it might only provide half-throttle, and it will usually turn on a warning light. Fords use a light shaped like a wrench, but other vehicles may use an ETC warning light shaped like inverted parentheses with a lightning bolt between them.

If one (redundant) sensor doesn’t work or doesn’t agree with the other (redundant) sensor as it should, fail-safe mode kicks in, reducing or eliminating throttle response for safety purposes.

Richard McCuistian, ASE Certified Master Automobile Technician

What are the Possible Causes of the P2135 Code?

Error code P2135  can have a lot of potential causes. Below are just some of the possible issues that may have resulted in the P2135 code:

  • Accelerator pedal position assembly failure
  • TPS failure
  • PCM issues (e.g., software is outdated)
  • Circuit problems (e.g., damaged wires and poor connections) 

What are the Common Symptoms of the P2135 Code?

You may notice one or more of the following symptoms when error code P2135 is set:

  • Decreased engine performance
  • Engine going into “limp home” (Reduced Power) mode
  • Frequent stalling or sudden stopping
  • Check engine light is on
See also  P0123 Code: Throttle / Pedal Position Sensor "A" Circuit High
driving on highway
A decrease in your car’s engine performance can be a sign of a logged P2135 code.

How to Diagnose the P2135 Code

Some very crucial reminders below if you plan to diagnose the code yourself:

  1. Don’t ever open the throttle body with your fingers, even with the engine switched off or with the throttle body removed. On some vehicles, this can ruin the throttle body mechanism so that it has to be replaced. Always have an assistant hold the throttle pedal down to open the throttle plate.
  2. NEVER clean the throttle body with your fingers or put your fingers into the throttle body for ANY REASON. Always use a brush, because if the throttle body plate is driven closed (like if the assistant releases the pedal) the throttle body will seriously injure your fingers. Keep your fingers out of the throttle body at all times.

Because many issues can trigger the P2135 code, you may have a hard time pinpointing its exact cause. Use these detailed video references as a guide to help you diagnose the code properly:

How to Fix the P2135 Code

If you are not confident with your automotive know-how and DIY skills, let your mechanic take care of the issue. Otherwise, you may address the P2135 code yourself. 

Identify what triggered the code, then figure out how to resolve it by doing your research on confirmed fixes that apply to your specific vehicle. You can also use these online auto repair resources and guides or get an ALLDATA subscription (for comprehensive factory repair information) in order to get more guidance.

Be sure to consult your owner’s manual before starting the repair process. What works for one vehicle might not work for another because different makes and models typically have their specific repair instructions. You don’t want to accidentally make the problem worse with an inappropriate fix. 

When in doubt, contact your mechanic. 

Other Notes About Code P2135

Other vehicle manufacturers will label this code differently, such as: “throttle position sensor circuit range/performance” on a Nissan Infiniti or “electronic throttle control system malfunction power management” on a Hyundai.

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

Where To Get Parts To Resolve the P2135 Code

DTC P2135 can be caused by a number of faulty parts, including the PCM and the throttle position sensor. If the P2135 code remains unresolved, you might continue to experience decreased engine performance and frequent stalling or sudden stopping. That’s why it’s important to address whatever’s causing the P2135 code as soon as possible. Fortunately, you can easily get the parts you need at CarParts.com.

If you’re looking to buy replacement parts without leaving the comforts of home, trust CarParts.com. Our easy-to-navigate website lets you choose from our wide variety of quality aftermarket parts. Our vehicle selector allows you to easily find parts that will surely fit your vehicle’s year, make, and model.

Place your order for a new throttle position sensor and other parts at CarParts.com today.

Products Mentioned in this Guide

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Replacement – Throttle Position Sensor
, P2135 Code: Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation
$10.49 Price and rating may change from the time content is published.
Replacement – Accelerator Pedal Position Sensor – Direct Fit, Sold individually
, P2135 Code: Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation
$79.99 Price and rating may change from the time content is published.
Replacement – Throttle Body, 1.8L/2.0L/2.4L Engines, 4 Cyl
, P2135 Code: Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation
$81.49 Price and rating may change from the time content is published.
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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