WOMS
B code body Medium severity

B1387 Oil Temperature Sensor Circuit Open

The OBD2 code B1387 indicates that there is an open circuit in the oil temperature sensor, meaning the sensor is not providing a signal to the vehicle's computer, which can affect engine performance and monitoring

Definition

The OBD2 code B1387 indicates that there is an open circuit in the oil temperature sensor, meaning the sensor is not providing a signal to the vehicle's computer, which can affect engine performance and monitoring

Common causes

  • Faulty oil temperature sensor
  • Open circuit in wiring or connectors
  • Corroded or damaged connectors
  • Short circuit in the wiring harness
  • Poor ground connection
  • Faulty engine control module (ECM)

Common misdiagnoses

  • Faulty oil temperature sensor
  • Wiring issues or damaged connectors
  • Engine control module (ECM) malfunction
  • Oil level or quality issues
  • Faulty thermostat
  • Incorrect oil type or viscosity
  • Other sensor failures (e.g., coolant temperature sensor)
  • Short circuits in the wiring harness

Troubleshooting steps

  1. 1. Verify the Code

    Use an OBD-II scanner to confirm the presence of the B1387 code. Check for any additional codes that may provide more context

  2. 2. Inspect the Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors associated with the oil temperature sensor for any signs of damage, corrosion, or loose connections

  3. 3. Connector Condition

    Ensure that the connectors are securely attached and that there are no bent pins or broken clips

  4. 4. Test the Oil Temperature Sensor

    Resistance Check: Use a multimeter to measure the resistance of the oil temperature sensor. Compare the readings to the manufacturer’s specifications

  5. 5. Sensor Functionality

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

  6. 6. Check for Open Circuits

    Continuity Test: With the vehicle off, perform a continuity test on the wiring between the oil temperature sensor and the engine control module (ECM). Look for any breaks in the wire

  7. 7. Ground Check

    Ensure that the sensor has a proper ground connection. A poor ground can lead to an open circuit

  8. 8. Inspect the Engine Control Module (ECM)

    ECM Functionality: If the wiring and sensor are in good condition, the issue may lie within the ECM. Check for any software updates or known issues with the ECM related to the oil temperature sensor

  9. 9. Reprogramming

    In some cases, reprogramming or resetting the ECM may resolve the issue

  10. 10. Clear the Code and Test Drive

    After performing the above checks and repairs, clear the code using the OBD-II scanner and take the vehicle for a test drive to see if the code reappears

  11. 11. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the B1387 code for your specific vehicle make and model. Manufacturers may have issued guidance on common issues and fixes

  12. 12. Seek Professional Help

    If the problem persists after following these steps, it may be best to consult a professional mechanic or technician who has experience with your vehicle’s make and model.Additional Tips: - Always refer to the vehicle’s service manual for specific testing procedures and specifications. - Ensure that you are working in a safe environment and take necessary precautions when dealing with electrical components. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1387 code