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P0390 Camshaft Position Sensor "B" Circuit (Bank 2)

The OBD2 code P0390 indicates a malfunction in the camshaft position sensor "B" circuit for bank 2, which can affect the engine's timing and performance

Definition

The OBD2 code P0390 indicates a malfunction in the camshaft position sensor "B" circuit for bank 2, which can affect the engine's timing and performance

Common causes

  • Faulty camshaft position sensor
  • Damaged wiring or connectors
  • Faulty engine control module (ECM)
  • Timing chain or belt issues
  • Oil contamination or low oil level
  • Faulty crankshaft position sensor
  • Poor electrical connections
  • Sensor alignment issues

Common misdiagnoses

  • Faulty camshaft position sensor
  • Faulty crankshaft position sensor
  • Wiring issues or shorts in the sensor circuit
  • Engine control module (ECM) failure
  • Timing chain or belt issues
  • Fuel delivery problems
  • Ignition system faults
  • Vacuum leaks
  • Other sensor failures (e.g., VVT sensor)
  • Mechanical engine problems (e.g., valve timing 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 and help identify related issues

  2. 2. Inspect the Camshaft Position Sensor

    Locate the camshaft position sensor for Bank 2. Inspect the sensor for any visible damage, corrosion, or loose connections

  3. 3. Ensure that the sensor is properly mounted and that there are no signs of oil or coolant leaks that could affect its operation

  4. 4. Examine the Wiring and Connectors

    Inspect the wiring harness and connectors leading to the camshaft position sensor. Look for frayed wires, broken connectors, or signs of wear

  5. 5. Check for any signs of short circuits or open circuits in the wiring

  6. 6. Test the Camshaft Position Sensor

    Use a multimeter to test the resistance and voltage output of the camshaft position sensor according to the manufacturer’s specifications

  7. 7. If the sensor is faulty, it may need to be replaced

  8. 8. Check the Power and Ground

    Verify that the camshaft position sensor is receiving the correct voltage and ground. Use a multimeter to check for power at the sensor connector

  9. 9. If there is no power or ground, trace the wiring back to the engine control module (ECM) to identify any issues

  10. 10. Inspect the Timing Components

    Check the timing belt or chain for proper alignment and condition. A misaligned or damaged timing component can affect the camshaft position sensor's readings

  11. 11. If the timing is off, it may require adjustment or replacement

  12. 12. Check the Engine Control Module (ECM)

    If all other components are functioning correctly, the issue may lie with the ECM itself. Check for any software updates or known issues with the ECM related to the camshaft position sensor

  13. 13. Clear the Codes and Test Drive

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

  14. 14. Take the vehicle for a test drive to see if the code reappears. Monitor the engine performance and any related symptoms

  15. 15. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the camshaft position sensor for your specific make and model. Manufacturers may have issued guidance on common issues and fixes

  16. 16. Seek Professional Help

    If you are unable to resolve the issue after following these steps, it may be best to consult a professional mechanic who has experience with your vehicle make and model. By following these troubleshooting steps, you can systematically identify and address the cause of the P0390 code