WOMS
P code powertrain Medium severity

P0399 Camshaft Position Sensor 'B' Circuit Intermittent (Bank 2)

The OBD2 code P0399 indicates an intermittent issue with the camshaft position sensor 'B' circuit on bank 2 of the engine, which can affect the engine's timing and performance

Definition

The OBD2 code P0399 indicates an intermittent issue with the camshaft position sensor 'B' circuit on bank 2 of the engine, which can affect the engine's timing and performance

Common causes

  • Faulty camshaft position sensor
  • Damaged wiring or connectors
  • Poor electrical connections
  • Faulty engine control module (ECM)
  • Timing chain/belt issues
  • Oil contamination
  • Sensor alignment issues
  • Mechanical engine problems

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., low compression)

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are other issues affecting the camshaft position sensor

  2. 2. Inspect the Camshaft Position Sensor

    Locate the camshaft position sensor on Bank 2 and visually inspect it for any signs of damage, corrosion, or loose connections

  3. 3. Ensure that the sensor is securely mounted and that the wiring harness is intact

  4. 4. Check Wiring and Connectors

    Inspect the wiring and connectors leading to the camshaft position sensor for fraying, breaks, or corrosion

  5. 5. Ensure that the connectors are clean and making good contact. Sometimes, simply reseating the connector can resolve intermittent issues

  6. 6. Test the Camshaft Position Sensor

    Use a multimeter to test the sensor's resistance and voltage output according to the manufacturer's specifications

  7. 7. If the sensor is out of spec, it may need to be replaced

  8. 8. Check for Ground Issues

    Ensure that the camshaft position sensor has a good ground connection. A poor ground can lead to intermittent signals

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

  10. 10. Inspect Timing Components

    If the camshaft position sensor is functioning correctly, check the timing components (timing belt/chain) for wear or misalignment. A timing issue can cause the sensor to read incorrectly

  11. 11. Scan for Signal Interference

    Use an oscilloscope to check the signal waveform from the camshaft position sensor. Look for irregularities that could indicate interference or a faulty sensor

  12. 12. Check Engine Control Module (ECM)

    In rare cases, the issue may lie with the ECM itself. Ensure that the ECM is functioning properly and that there are no software issues

  13. 13. Clear Codes and Test Drive

    After performing repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code reappears

  14. 14. Consult Repair Manual

    If the issue persists, consult the vehicle’s repair manual for specific diagnostic procedures related to the camshaft position sensor and the P0399 code.1

  15. 15. Seek Professional Help

    If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic who has experience with your specific vehicle make and model. By following these steps, you should be able to identify the cause of the P0399 code and take appropriate action to resolve the issue