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P code powertrain Medium severity

P1114 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage/IAT - B Circuit Low Input

The OBD2 code P1114 indicates that there is an intermittent low voltage issue in the Engine Coolant Temperature (ECT) sensor circuit or a low input signal from the Intake Air Temperature (IAT) sensor circuit

Definition

The OBD2 code P1114 indicates that there is an intermittent low voltage issue in the Engine Coolant Temperature (ECT) sensor circuit or a low input signal from the Intake Air Temperature (IAT) sensor circuit

Common causes

  • Faulty ECT sensor
  • Damaged wiring or connectors
  • Poor electrical connections
  • Short circuit in the wiring
  • Open circuit in the wiring
  • Corroded terminals
  • Faulty engine control module (ECM)
  • Low coolant level
  • Grounding issues

Common misdiagnoses

  • Faulty ECT sensor
  • Wiring issues or damaged connectors
  • Faulty Engine Control Module (ECM)
  • Thermostat malfunction
  • Coolant leaks
  • Air in the cooling system
  • Faulty intake air temperature (IAT) sensor
  • Incorrect coolant type or mixture
  • Temperature gauge malfunction
  • Faulty radiator fan switch

Troubleshooting steps

  1. 1. Check the Code and Freeze Frame Data

    Use an OBD-II scanner to confirm the P1114 code and check for any additional codes that may provide more context

  2. 2. Review freeze frame data to understand the conditions under which the code was set

  3. 3. Visual Inspection

    Inspect the wiring and connectors associated with the ECT and IAT sensors for any signs of damage, corrosion, or loose connections

  4. 4. Look for frayed wires, broken connectors, or any signs of wear that could lead to intermittent connections

  5. 5. Test the ECT and IAT Sensors

    Use a multimeter to measure the resistance of the ECT and IAT sensors. Compare the readings to the specifications provided in the vehicle’s service manual

  6. 6. If the resistance is out of range, the sensor may be faulty and should be replaced

  7. 7. Check the Sensor Voltage Supply

    With the ignition on (engine off), check the voltage at the sensor connector. You should see a reference voltage (usually around 5V) supplied to the sensor

  8. 8. If the voltage is low or absent, trace the wiring back to the Engine Control Module (ECM) to identify any breaks or shorts

  9. 9. Inspect the Ground Circuit

    Ensure that the ground connection for the ECT and IAT sensors is secure and free of corrosion

  10. 10. Use a multimeter to check for continuity between the sensor ground and the vehicle ground

  11. 11. Check for Short Circuits

    Inspect the wiring for any signs of short circuits to ground or to other circuits that could cause low voltage readings

  12. 12. Use a multimeter to check for continuity between the sensor wires and ground

  13. 13. Test the Engine Control Module (ECM)

    If all other components check out, the issue may lie within the ECM itself. Ensure that the ECM is functioning properly and that it is receiving the correct signals from the sensors

  14. 14. Reflashing or replacing the ECM may be necessary if it is determined to be faulty

  15. 15. Clear the Codes and Test Drive

    After performing repairs or replacements, clear the codes using the OBD-II scanner

  16. 16. Take the vehicle for a test drive to see if the code reappears. Monitor the ECT and IAT readings to ensure they are within normal operating ranges

  17. 17. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the P1114 code for your specific vehicle make and model. There may be known issues or recalls that could provide additional guidance

  18. 18. Seek Professional Help

    If you are unable to resolve the issue after following these steps, consider seeking assistance from a professional mechanic or automotive technician who has experience with OBD-II diagnostics. By following these troubleshooting steps, you should be able to identify and resolve the underlying issue causing the P1114 code