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P code powertrain High severity

P2768 Input/Turbine Speed Sensor "B" Circuit Intermittent

The OBD2 code P2768 indicates an intermittent issue with the Input/Turbine Speed Sensor "B" circuit, which may affect the transmission's ability to accurately monitor the input speed, potentially leading to shifting...

Definition

The OBD2 code P2768 indicates an intermittent issue with the Input/Turbine Speed Sensor "B" circuit, which may affect the transmission's ability to accurately monitor the input speed, potentially leading to shifting problems or poor transmission performance

Common causes

  • Faulty input/turbine speed sensor "B"
  • Damaged wiring or connectors
  • Poor electrical connections
  • Transmission fluid issues (low level, contamination)
  • Faulty transmission control module (TCM)
  • Internal transmission problems
  • Corroded terminals or connectors

Common misdiagnoses

  • Faulty Transmission Control Module (TCM)
  • Faulty Input/Turbine Speed Sensor "A"
  • Wiring issues or short circuits in the sensor circuit
  • Faulty Transmission Fluid Temperature Sensor
  • Transmission fluid issues (contamination or low level)
  • Internal transmission problems (e.g., clutch or valve body issues)
  • Faulty Engine Control Module (ECM)
  • Incorrectly diagnosed engine performance issues

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 additional context for the issue

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors associated with the Input/Turbine Speed Sensor "B". Look for

  3. 3. Damaged, frayed, or corroded wires

  4. 4. Loose or corroded connectors

  5. 5. Signs of wear or exposure to heat or moisture

  6. 6. Test the Sensor

    If the wiring appears to be in good condition, test the Input/Turbine Speed Sensor "B" itself

  7. 7. Use a multimeter to check the resistance of the sensor. Compare the readings to the specifications in the vehicle’s service manual

  8. 8. If the sensor is a Hall effect or variable reluctance type, check for proper voltage and signal output while the engine is running

  9. 9. Check the Transmission Fluid

    Low or dirty transmission fluid can affect sensor performance. Check the fluid level and condition

  10. 10. If the fluid is low, top it off with the correct type of transmission fluid

  11. 11. If the fluid is dirty or burnt, consider a transmission fluid change

  12. 12. Inspect the Transmission Control Module (TCM)

    The TCM processes signals from the speed sensors. Ensure that the TCM is functioning correctly

  13. 13. Check for any signs of damage or corrosion

  14. 14. Ensure that the TCM is properly connected and that there are no issues with its power supply

  15. 15. Perform a Wiggle Test

    With the vehicle running, gently wiggle the wiring harness and connectors associated with the Input/Turbine Speed Sensor "B". If the code returns or the engine behavior changes, it may indicate a wiring issue

  16. 16. Check for Ground Issues

    Ensure that the sensor has a good ground connection. A poor ground can lead to intermittent signals

  17. 17. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner. Take the vehicle for a test drive to see if the code returns

  18. 18. Seek Professional Help

    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 transmission issues and OBD-II diagnostics. By following these steps, you should be able to identify and address the cause of the P2768 code