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P2127 OBD-II Trouble Code: Throttle/Pedal Position Sensor/Switch 'E' Circuit Low

Check Engine Light

P2127 code definition

The P2127 code is a generic OBD-II diagnostic trouble code indicating a fault with the throttle or pedal position sensor. This code may be seen with other throttle and pedal position sensor codes.

What the P2127 code means

The P2127 code means that the throttle or pedal position sensor switch E has a low input. The pedal position sensor is a sensor found on the gas pedal. The sensor tells the ECU when the gas pedal is depressed and how far it is depressed. When the ECU detects a low input from the pedal, it will trigger the Check Engine Light and the code P2127.

The Check Engine Light will be displayed on the dashboard. With the Check Engine Light, a failsafe mode may be set to prevent damage from being done to the vehicle. The failsafe mode will remain in effect until normal sensor operation is detected or the code is repaired.

What causes the P2127 code?

The most common causes of the P2127 code are:

  • Failed throttle or pedal position sensor
  • Open or short in the wiring harness
  • Poor or intermittent electrical connection
  • The vehicles ECU has failed or is failing

What are the symptoms of the P2127 code?

In all cases of the P2127 code, the Check Engine Light will be illuminated on the dashboard. In addition to the Check Engine Light, the car may not respond when the throttle is depressed, the vehicle may run poorly, and may stall or exhibit lack of power upon acceleration.

How does a mechanic diagnose the P2127 code?

Mechanics will begin by hooking up a scan tool to the vehicle's DLC port and checking for any codes that the ECU has stored. There may be multiple codes including history or pending codes. All codes will be noted as well as their associated freeze frame data, which tells us the circumstances the car was under, such as: RPM, vehicle speed, coolant temperature, and more. This information is critical when attempting to duplicate the symptoms.

Next, all codes will be cleared and a test drive performed under as close to the freeze frame conditions as possible. The technician will only attempt the test drive if the vehicle is safe to operate.

A visual inspection will then be performed looking for a damaged gas pedal, worn or exposed wiring, and broken components.

Afterwards, the scan tool will be used to view the live data and watch the throttle and gas pedal position's sensor e-values. These values should change as the throttle is depressed and released. Then the voltage will be checked at the pedal position sensor.

Lastly, the manufactures ECU testing procedure will be performed, and this will vary between make and model of vehicle.

Common mistakes when diagnosing the P2127 code

Mistakes are common when steps are not performed in the proper order or are skipped entirely. Even experienced technicians can miss easy problems when simple items, such as the visual inspection are not performed.

How serious is the P2127 code?

In most cases, the P2127 code will not prevent the vehicle from being driven to a safe location once the malfunction is detected. In rare cases, depressing the gas pedal will not elicit any response and the vehicle will not move. The vehicle should not be attempted to be driven when this occurs, or if you are experiencing any other serious driveability concerns.

What repairs can fix the P2127 code?

The most likely repairs for the P2127 code are:

Additional comments for consideration regarding the P2127 code

In cases where pressing the gas pedal gives no response, it can be a scary position to be in. When this occurs, do not attempt to operate the vehicle.

P2127 can require specialized tools when performing diagnosis. One such tool is a professional grade scan tool, these scan tools provide the information technicians need to diagnose P2127 and many other codes properly. Normal scan tools may only allow the code to be viewed and cleared, whereas the professional grade scan tool allows graphing of things such as sensor voltage and provides access to the datasteam of the vehicle which can be watched for changes in values over time.

Need help with a P2127 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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