WOMS
P code powertrain High severity

P1120 Throttle position sensor out of range

The OBD2 code P1120 indicates that the throttle position sensor (TPS) is reporting a voltage or signal that is outside the expected range, which can affect engine performance and response

Definition

The OBD2 code P1120 indicates that the throttle position sensor (TPS) is reporting a voltage or signal that is outside the expected range, which can affect engine performance and response

Common causes

  • Faulty throttle position sensor (TPS)
  • Wiring issues or damaged connectors
  • Poor electrical connections
  • Throttle body malfunction
  • Engine control module (ECM) issues
  • Vacuum leaks
  • Incorrectly calibrated TPS
  • Mechanical binding in the throttle linkage

Common misdiagnoses

  • Faulty throttle position sensor (TPS)
  • Wiring issues or short circuits
  • Faulty accelerator pedal position sensor
  • Engine control module (ECM) failure
  • Vacuum leaks
  • Dirty or faulty mass air flow (MAF) sensor
  • Fuel delivery issues
  • Intake manifold gasket leaks
  • Faulty idle air control (IAC) valve
  • Transmission issues

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. Visual Inspection

    Check the TPS for any physical damage, corrosion, or loose connections. Ensure that the wiring harness and connectors are secure and free from damage

  4. 4. Connector Check

    Make sure the connector is clean and free of moisture or debris

  5. 5. Test the Throttle Position Sensor

  6. 6. Voltage Check

    Use a multimeter to measure the voltage output of the TPS. Typically, the TPS should provide a voltage between 0.5V to 4.5V depending on the throttle position. Check the specifications for your specific vehicle

  7. 7. Resistance Check

    If applicable, check the resistance of the TPS at various throttle positions to ensure it changes smoothly and consistently

  8. 8. Inspect the Throttle Body

  9. 9. Clean the Throttle Body

    Carbon buildup can affect the operation of the throttle body and TPS. Clean the throttle body and ensure that the throttle plate moves freely

  10. 10. Check for Mechanical Issues

    Ensure that there are no obstructions preventing the throttle plate from moving properly

  11. 11. Check the Wiring and Ground

  12. 12. Wiring Inspection

    Inspect the wiring from the TPS to the ECM for any signs of wear, fraying, or short circuits

  13. 13. Ground Check

    Ensure that the TPS has a good ground connection. A poor ground can lead to erratic sensor readings

  14. 14. Test the ECM

    If all other components check out, the issue may lie with the ECM itself. Testing or reprogramming the ECM may be necessary, but this is usually a last resort

  15. 15. Clear the Codes and Test Drive

    After performing repairs or replacements, clear the trouble codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

  16. 16. Consult Repair Manual

    If the issue persists, consult the vehicle’s repair manual for specific diagnostic procedures related to the TPS and P1120 code

  17. 17. Seek Professional Help

    If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic for further diagnosis. By following these steps, you should be able to identify and resolve the issue related to the P1120 code