WOMS
B code body Medium severity

B1390 Oil Temperature Sensor Circuit Short To Ground

The OBD2 code B1390 indicates a malfunction in the oil temperature sensor circuit, specifically that there is a short to ground, which means the circuit is unintentionally connected to the ground, causing incorrect...

Definition

The OBD2 code B1390 indicates a malfunction in the oil temperature sensor circuit, specifically that there is a short to ground, which means the circuit is unintentionally connected to the ground, causing incorrect readings or failure of the sensor

Common causes

  • Damaged wiring or connectors
  • Shorted sensor
  • Faulty oil temperature sensor
  • Corroded connections
  • Grounding issues in the circuit
  • Faulty engine control module (ECM)

Common misdiagnoses

  • Faulty oil temperature sensor
  • Wiring issues or damaged harness
  • Engine control module (ECM) malfunction
  • Shorted or corroded connectors
  • Incorrect oil level or type
  • Other sensor failures (e.g., coolant temperature sensor)
  • Faulty gauge or display issues
  • Grounding issues in the electrical system

Troubleshooting steps

  1. 1. Check the Code and Freeze Frame Data

    Use an OBD-II scanner to confirm the B1390 code is present

  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 oil temperature sensor

  4. 4. Look for signs of damage, corrosion, or loose connections

  5. 5. Check for any frayed wires or shorts to ground in the harness

  6. 6. Test the Oil Temperature Sensor

    Disconnect the oil temperature sensor and measure its resistance with a multimeter

  7. 7. Compare the resistance readings to the manufacturer’s specifications. If the sensor is out of spec, it may need to be replaced

  8. 8. Check for Short to Ground

    With the sensor disconnected, use a multimeter to check for continuity between the sensor signal wire and ground

  9. 9. If there is continuity, there is likely a short in the wiring harness that needs to be repaired

  10. 10. Inspect the Ground Circuit

    Check the ground connections for the oil temperature sensor and ensure they are clean and secure

  11. 11. Test the ground circuit for continuity and proper voltage

  12. 12. Check the Power Supply

    Verify that the oil temperature sensor is receiving the correct voltage from the vehicle’s power supply

  13. 13. If the voltage is incorrect, trace back to the power source to identify any issues

  14. 14. Scan for Additional Codes

    Check for any other related trouble codes that may provide additional context or indicate a broader issue

  15. 15. Clear the Codes and Test Drive

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

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

  17. 17. Seek Professional Help

    If you are unable to resolve the issue after these steps, consider seeking assistance from a professional mechanic or automotive technician.Additional Tips: - Always ensure that you are working safely and disconnect the battery when working on electrical components. - Document any changes or repairs made during the troubleshooting process for future reference. By following these steps, you should be able to identify and address the cause of the B1390 code effectively