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P codepowertrainMedium severity

P0122Throttle Position Sensor/Switch A Circuit Low Input

The OBD2 code P0122 indicates that the Throttle Position Sensor (TPS) is sending a low voltage signal to the engine control module (ECM), suggesting a potential issue with the sensor or its circuit

Definition

The OBD2 code P0122 indicates that the Throttle Position Sensor (TPS) is sending a low voltage signal to the engine control module (ECM), suggesting a potential issue with the sensor or its circuit

Common causes

  • Faulty throttle position sensor (TPS)
  • Damaged wiring or connectors
  • Poor electrical connections
  • Throttle body issues
  • Malfunctioning engine control module (ECM)
  • Vacuum leaks
  • Corroded or dirty sensor terminals

Common misdiagnoses

  • Faulty throttle position sensor
  • Wiring issues or short circuits
  • Faulty engine control module (ECM)
  • Vacuum leaks
  • Faulty accelerator pedal position sensor
  • Malfunctioning mass air flow sensor
  • Fuel delivery issues
  • Ignition system problems

Troubleshooting steps

  1. 1.Check for Additional Codes

    Before proceeding, check for any other related trouble codes that may provide more context to the issue

  2. 2.Inspect the Throttle Position Sensor

  3. 3.Visually inspect the TPS for any signs of damage, corrosion, or loose connections

  4. 4.Ensure that the sensor is properly mounted and that there are no physical obstructions

  5. 5.Check the Wiring and Connectors

  6. 6.Inspect the wiring harness and connectors leading to the TPS for fraying, breaks, or corrosion

  7. 7.Ensure that the connectors are securely attached and free of dirt or moisture

  8. 8.Test the Throttle Position Sensor

  9. 9.Use a multimeter to measure the voltage output of the TPS. The voltage should change smoothly as the throttle is opened and closed

  10. 10.Compare the readings to the specifications provided in the vehicle’s service manual. A low voltage reading (typically below 0.5 volts) may indicate a faulty sensor

  11. 11.Check the Power and Ground

  12. 12.Verify that the TPS is receiving the correct voltage supply (usually 5 volts) from the vehicle’s power source

  13. 13.Check the ground connection for the TPS to ensure it is solid and free of corrosion

  14. 14.Inspect the Throttle Body

  15. 15.Check the throttle body for any carbon buildup or obstructions that could affect the throttle position

  16. 16.Ensure that the throttle plate moves freely and is not sticking

  17. 17.Test the Engine Control Module (ECM)

  18. 18.If all other components check out, the issue may lie with the ECM. Ensure that the ECM is functioning properly and that it is receiving the correct signals from the TPS

  19. 19.Clear the Codes and Test Drive

  20. 20.After performing repairs or replacements, clear the trouble codes using an OBD-II scanner

  21. 21.Take the vehicle for a test drive to see if the code reappears

  22. 22.Consult a Professional

    If the issue persists after performing these steps, it may be best to consult a professional mechanic for further diagnosis. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P0122 code