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P2126 OBD-II Trouble Code: Throttle/Pedal Position Sensor/Switch E Circuit Range/Performance

Check Engine Light

Diagnostic Trouble Code (DTC): P2126

P2126 code definition

Throttle/Pedal Position Sensor/Switch E Circuit Range/Performance

Related Trouble Codes:

  • P2120: Throttle/Pedal Position Sensor/Switch D Circuit
  • P2121: Throttle/Pedal Position Sensor/Switch D Circuit Range/Performance
  • P2122: Throttle/Pedal Position Sensor/Switch D Circuit Low Input
  • P2123: Throttle/Pedal Position Sensor/Switch D Circuit High Input
  • P2124: Throttle/Pedal Position Sensor/Switch D Circuit Interm
  • P2125: Throttle/Pedal Position Sensor/Switch E Circuit
  • P2127: Throttle/Pedal Position Sensor/Switch E Circuit Low Input
  • P2128: Throttle/Pedal Position Sensor/Switch E Circuit High Input
  • P2129: Throttle/Pedal Position Sensor/Switch E Circuit Interm
  • P2130: Throttle/Pedal Position Sensor/Switch F Circuit
  • P2131: Throttle/Pedal Position Sensor/Switch F Circuit Range/Performance
  • P2132: Throttle/Pedal Position Sensor/Switch F Circuit Low Input
  • P2133: Throttle/Pedal Position Sensor/Switch F Circuit High Input
  • P2134: Throttle/Pedal Position Sensor/Switch F Circuit Interm

What the P2126 code means

The P2126 diagnostic trouble code is an indication that there is a range/performance issue with the E circuit of the throttle/pedal position sensor switch.

The correct amount of air and fuel are required for engines to run smoothly. The accelerator pedal opens the throttle plate when it is pressed down in order to allow air into the engine. The throttle plate, which is located on the throttle body assembly, allows or restricts air from getting into the engine when it is opened or closed by the accelerator pedal. The accelerator pedal position (APP) sensor sends information to the Powertrain Control Module (PCM) through a voltage signal. This voltage signal dictates how much the throttle body plate should open. When the APP sensor is not working properly, the PCM will store the P2126 diagnostic trouble code and the Check Engine Light will come on.

What causes the P2126 code?

  • Faulty APP sensor
  • APP sensor harness is open or shorted
  • APP sensor wiring is frayed or broken
  • APP sensor circuit has a poor electrical connection
  • APP sensor connector is corroded or has bent pins
  • Defective throttle actuator control motor
  • Defective throttle position (TP) actuator
  • Defective TP sensor
  • Corroded, open, or shorted wiring or connectors in the throttle actuator motor
  • Loose control module ground strap or broken ground wire
  • Faulty PCM

What are the symptoms of the P2126 code?

  • Check Engine Light is on
  • No acceleration
  • Poor acceleration
  • Car may lack engine power
  • Black smoke when starting car
  • Car won’t start
  • Misfire condition
  • Stalling condition

How does a mechanic diagnose the P2126 code?

  • Uses an OBD-II scanner to collect all trouble codes that have been stored by the PCM, as well as freeze frame data.

  • Inspects the APP sensor connector for corrosion, bent pins, or damaged plastic (repairs or replaces connector as necessary)

  • Inspects the APP sensor wiring for shorts, breaks, or frays (repairs or replaces as necessary)

  • Clears all stored trouble codes from the PCM and completes a test drive to see if the P2126 trouble code comes back

  • If the P2126 trouble code does come back, compares the voltage signal reading of the APP sensor with the manufacturer’s predetermined specifications

If the voltage signal reading of the APP sensor does not fall within specifications, the APP sensor will need to be replaced.

  • Clears all stored trouble codes from the PCM and completes a test drive to see if the P2126 trouble code comes back

  • If the P2126 trouble code does come back, checks the voltage signal of the TP sensor

  • Compares the voltage signal reading of the TP sensor with the manufacturer’s predetermined specifications

If the voltage signal reading does not fall within specifications, the TP sensor will need to be replaced.

  • Clears all stored trouble codes from the PCM and completes a test drive to see if the P2126 trouble code comes back.

  • If the P2126 trouble code does come back, compares the voltage signal of the TP actuator with the manufacturer’s predetermined specifications (it is important to note that this test should be done while the motor is running)

If the voltage signal reading does not fall within specifications, the TP actuator is faulty

If the voltage signal reading does fall within specifications, the throttle actuator control motor is faulty

To properly repair and replace the TP actuator and/or the throttle actuator control motor, the throttle body assembly will need to be replaced.

  • Diagnoses any other diagnostic trouble codes that have been stored by the PCM in the order that they have been listed

If diagnosis and repair of all listed trouble codes have been completed and pass inspection, it is possible that there is a problem with the PCM, which is rare, but possible.

Common mistakes when diagnosing the P2126 code

  • Replacing the APP sensor when the throttle body assembly should have been replaced

  • Failing to inspect the wiring and connectors before replacing the APP sensor and/or the throttle body assembly

How serious is the P2126 code?

The P2126 diagnostic trouble code can cause the vehicle to lose power or acceleration when it is necessary to maneuver through traffic. This makes driving conditions extremely dangerous. For this reason, the P2126 diagnostic trouble code is considered serious and should be diagnosed and repaired as soon as possible.

What repairs can fix the P2126 code?

  • Replacing the APP sensor

  • Replacing or repairing APP sensor wiring harness opens and/or shorts

  • Repairing or replacing APP sensor wiring that is frayed or broken

  • Repairing or replacing APP sensor circuitry that has poor electrical connection

  • Repairing or replacing APP sensor connector that is corroded or has bent pins

  • Replacing throttle actuator control motor

  • Replacing TP actuator

  • Replacing TP sensor

  • Replacing throttle actuator motor wiring or connectors that are open, shorted, or corroded

  • Replacing and reprogramming PCM

Additional comments for consideration regarding the P2126 code

It is common for problems with the APP sensor or the throttle body assembly to cause the P2126 diagnostic trouble code to be stored by the PCM. Take time when diagnosing this trouble code to make sure the correct component is being replaced. If additional diagnostic trouble codes have been stored by the PCM, these codes should be diagnosed in the same order that they are listed.

Need help with a P2126 code?

YourMechanic offers certified 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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