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P code powertrain Medium severity

P1123 Throttle Position Sensor In Range But Higher Than Expected

The OBD2 code P1123 indicates that the throttle position sensor is functioning within its range but is reporting a higher voltage or position than what the engine control module (ECM) expects, suggesting a potential...

Definition

The OBD2 code P1123 indicates that the throttle position sensor is functioning within its range but is reporting a higher voltage or position than what the engine control module (ECM) expects, suggesting a potential issue with the sensor or its calibration

Common causes

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

Common misdiagnoses

  • Throttle Position Sensor (TPS) failure
  • Accelerator Pedal Position Sensor issues
  • Wiring or connector problems
  • Engine control module (ECM) malfunction
  • Vacuum leaks
  • Intake air temperature sensor issues
  • Mass air flow (MAF) sensor problems
  • Fuel delivery issues
  • Air filter blockage
  • Exhaust gas recirculation (EGR) system faults

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context for the issue

  2. 2. Inspect the Throttle Position Sensor

  3. 3. Visual Inspection

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

  4. 4. Testing the TPS

    Use a multimeter to measure the voltage output of the TPS at various throttle positions. Compare the readings to the manufacturer's specifications. The voltage should change smoothly as the throttle is opened and closed

  5. 5. Check for Mechanical Issues

  6. 6. Throttle Body Inspection

    Inspect the throttle body for carbon buildup or obstructions that could affect the throttle plate's movement. Clean the throttle body if necessary

  7. 7. Check for Binding

    Ensure that the throttle plate moves freely without binding or sticking. Check the throttle linkage and cable for any issues

  8. 8. Inspect the Wiring and Connectors

  9. 9. Wiring Inspection

    Look for damaged, frayed, or shorted wires in the TPS circuit. Pay special attention to the ground connections

  10. 10. Connector Check

    Ensure that the connectors are clean and making good contact. Corrosion or dirt can lead to poor electrical connections

  11. 11. Check for Vacuum Leaks

    A vacuum leak can cause the engine to run lean, which may affect the TPS readings. Inspect all vacuum hoses and intake manifold gaskets for leaks

  12. 12. Test the ECM

    If all other components check out, the issue may lie with the Engine Control Module itself. Ensure that the ECM is functioning correctly and is receiving the proper input from the TPS

  13. 13. Reset the Codes

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

  14. 14. Consult Technical Service Bulletins (TSBs)

    Check for any manufacturer-specific TSBs related to the P1123 code, as there may be known issues or recalls that apply to your vehicle

  15. 15. Professional Diagnosis

    If the problem persists after performing these steps, consider seeking help from a professional mechanic who can perform more advanced diagnostics. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P1123 code