P2127 Code: Throttle / Pedal Position Sensor / Switch “E” Circuit Low

If you see the P2127 code on the OBD scan tool, you’ll need to know what you’re up against before you even make plans of diagnosing and repairing it. Learn more about what this code means and what its common causes and symptoms are with this brief and informative guide.

What Does the P2127 Code Mean?

Diagnostic trouble code (DTC) P2127 stands for “Throttle/Pedal Position Sensor/Switch “E” Circuit Low. This code sets when the powertrain control module (PCM) detects an unusually low voltage from the throttle/pedal position sensor/switch. The “E” in this code’s meaning refers to a particular circuit, sensor, or area of a specific circuit designated as “E.” The specifics of the designation might depend on your vehicle’s manufacturer, so be sure to check your repair manual.

The electronic throttle control system (ECTS) is responsible for controlling the opening of the throttle valve. When the accelerator pedal is pressed, the accelerator pedal position sensor sends a signal to the PCM indicating how much power is requested from the engine. The PCM then adjusts the opening of the throttle plate accordingly. The expected voltage range from the throttle/pedal position sensor/switch might differ depending on the vehicle’s manufacturer.

If the PCM detects that the ECTS isn’t functioning as requested, it will set the P2127 code. It can also put the engine into “limp mode,” which limits engine RPM and reduces power.

Plugging a scan tool into your vehicle’s OBD-II port lets you see which trouble codes are set in your vehicle. If the DTC P2127 appears on your scan tool, it’s recommended that you take your vehicle to a mechanic for diagnosis and repairs as soon as possible. Driving with this trouble code is not advised.

Note: The definition of code P2127 might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P2127 Code?

Trouble codes, including P2127, can have multiple possible causes. Below are some of the most common causes of the P2127 code:

• Accelerator pedal position assembly failure
• Powertrain control module failure
• Throttle control motor failure
• TPS not mounted securely
• TPS circuit short to ground or another wire
• Faulty TPS
• Faulty PCM
• Wiring issue

What are the Common Symptoms of the P2127 Code?

Some trouble codes have noticeable symptoms, while others do not. As for the P2127 code, there are quite a few symptoms you might notice:

• Illuminated malfunction indicator lamp or check engine lamp
• Rough idle
• Stalling
• Surging
• Little to no acceleration
• Decreased engine performance
• The engine might enter limp home mode

How to Diagnose the P2127 Code

A lot of DTCs share similar symptoms, possible causes, and trouble areas. This is why it’s important to conduct a thorough diagnosis first when dealing with trouble codes, such as the P2127. Attempting repairs or replacing parts without determining the root cause of the issue can lead to even more severe issues down the line.

Fortunately, there are several resources you can use to find out more about the P2127 code and how the diagnostic process goes.

If you want to know more about troubleshooting and fixing the P2127, here are some videos that explain these processes in more detail:

How to Fix the P2127 Code

Trouble codes can have multiple possible causes, so there’s no single cure-all for all of them. A solution for the P2127 code in a Dodge might not work for the P2127 code in a Chevy. This is why it’s vital to determine the root cause first before making any repairs.

That said, not everyone has the proper tools and know-how to diagnose and fix DTCs. If you’re not confident in your OBD-II troubleshooting and repair skills, it might be best to leave the job to a certified mechanic or technician so you can avoid even larger repair bills later on.