FixItFor.Us
P code powertrain High severity

P2138 Throttle/Pedal Pos Sensor/Switch D / E Voltage Correlation

The OBD2 code P2138 indicates a voltage correlation issue between the throttle position sensor and the accelerator pedal position sensor, specifically between sensors D and E, suggesting a discrepancy in their readings

Definition

The OBD2 code P2138 indicates a voltage correlation issue between the throttle position sensor and the accelerator pedal position sensor, specifically between sensors D and E, suggesting a discrepancy in their readings

Common causes

  • Faulty throttle position sensor
  • Faulty accelerator pedal position sensor
  • Wiring issues (shorts, opens, or corrosion)
  • Poor electrical connections
  • Faulty engine control module (ECM)
  • Mechanical issues with the throttle body
  • Calibration issues or software glitches

Common misdiagnoses

  • Throttle body issues
  • Accelerator pedal assembly failure
  • Wiring or connector problems
  • Engine control module (ECM) failure
  • Faulty throttle position sensor (TPS)
  • Air intake issues
  • Vacuum leaks
  • Fuel delivery problems
  • Transmission issues
  • Other sensor malfunctions

Troubleshooting steps

  1. 1. Check for Additional Codes

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

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors associated with the throttle position sensor and accelerator pedal position sensor. Look for

  3. 3. Damaged, frayed, or corroded wires

  4. 4. Loose or corroded connectors

  5. 5. Signs of wear or short circuits

  6. 6. Test the Throttle Position Sensor (TPS)

    Use a multimeter to test the TPS for proper voltage and resistance. Check the following

  7. 7. Ensure the TPS is receiving the correct voltage from the ECM

  8. 8. Verify that the output voltage changes smoothly as the throttle is opened and closed

  9. 9. Test the Accelerator Pedal Position Sensor (APPS)

    Similarly, test the APPS for proper operation. Check for

  10. 10. Correct voltage input and output

  11. 11. Smooth voltage changes as the pedal is pressed and released

  12. 12. Check for Mechanical Issues

    Inspect the throttle body for any mechanical issues, such as

  13. 13. Sticking or binding throttle plates

  14. 14. Dirt or carbon buildup that may affect throttle operation

  15. 15. Ensure that the throttle body is functioning correctly and is not obstructed

  16. 16. Check for Software Updates

    Sometimes, the issue may be related to software glitches. Check with the manufacturer for any available updates for the ECM

  17. 17. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner

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

  19. 19. Replace Faulty Components

    If any of the sensors (TPS or APPS) are found to be faulty during testing, replace them

  20. 20. If wiring or connectors are damaged, repair or replace them as necessary

  21. 21. Check ECM Functionality

    If all sensors and wiring are functioning correctly, the issue may lie with the ECM itself. In this case, further diagnostics may be needed to determine if the ECM is faulty

  22. 22. Consult a Professional

    If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P2138 code