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P code powertrain High severity

P0718 Input/Turbine Speed Sensor A Circuit Intermittent

The OBD2 code P0718 indicates that there is an intermittent issue with the input or turbine speed sensor A circuit, which measures the rotational speed of the transmission input shaft

Definition

The OBD2 code P0718 indicates that there is an intermittent issue with the input or turbine speed sensor A circuit, which measures the rotational speed of the transmission input shaft

Common causes

  • Faulty input/turbine speed sensor
  • 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 engine control module (ECM)
  • Wiring issues or shorts in the harness
  • Faulty input/turbine speed sensor
  • Transmission fluid issues (low or contaminated fluid)
  • Faulty torque converter
  • Incorrectly installed or damaged transmission components
  • Other sensor failures (e.g., vehicle speed sensor)

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. Visual Inspection

  3. 3. Inspect the wiring and connectors associated with the Input/Turbine Speed Sensor. Look for signs of damage, corrosion, or loose connections

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

  5. 5. Test the Sensor

  6. 6. Use a multimeter to check the resistance of the Input/Turbine Speed Sensor. Compare the readings to the specifications provided in the vehicle’s service manual

  7. 7. If the sensor is a Hall effect type, check for proper voltage supply and ground

  8. 8. Check the Circuit

  9. 9. Inspect the wiring harness for any shorts, opens, or frayed wires. Pay special attention to areas where the wiring may be exposed to heat or abrasion

  10. 10. Use a multimeter to test the continuity of the circuit from the sensor to the engine control module (ECM)

  11. 11. Check the Transmission Fluid

  12. 12. Low or contaminated transmission fluid can affect sensor performance. Check the fluid level and condition, and replace it if necessary

  13. 13. Test the ECM

  14. 14. If the sensor and wiring are in good condition, the issue may lie with the ECM. Check for any software updates or reprogramming that may be needed

  15. 15. Clear Codes and Test Drive

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

  17. 17. Professional Diagnosis

  18. 18. If the problem persists after performing these steps, it may be necessary to consult a professional mechanic or technician who can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the issue related to the P0718 code. Always refer to the specific service manual for your vehicle for detailed procedures and specifications