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P code powertrain Medium severity

P047C Exhaust Pressure Sensor "B" Circuit Low

The OBD2 code P047C indicates that the exhaust pressure sensor "B" circuit is reading a low voltage or signal, which may suggest a malfunction in the sensor or its wiring

Definition

The OBD2 code P047C indicates that the exhaust pressure sensor "B" circuit is reading a low voltage or signal, which may suggest a malfunction in the sensor or its wiring

Common causes

  • Faulty exhaust pressure sensor
  • Damaged wiring or connectors
  • Short circuit in the sensor circuit
  • Open circuit in the sensor circuit
  • Corroded connectors
  • Vacuum leaks in the exhaust system
  • Faulty engine control module (ECM)

Common misdiagnoses

  • Faulty exhaust pressure sensor
  • Wiring issues or shorts in the sensor circuit
  • Faulty engine control module (ECM)
  • Exhaust leaks
  • Blocked or restricted exhaust system
  • Faulty turbocharger (if applicable)
  • Incorrectly installed or damaged exhaust pressure sensor
  • Issues with related sensors (e.g., MAP sensor)

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 multiple issues

  2. 2. Inspect the Exhaust Pressure Sensor

    Locate the exhaust pressure sensor "B" (refer to the vehicle's service manual for its exact location)

  3. 3. Visually inspect the sensor for any signs of damage, corrosion, or loose connections

  4. 4. Check Wiring and Connectors

    Inspect the wiring harness and connectors leading to the exhaust pressure sensor for any signs of wear, fraying, or damage

  5. 5. Ensure that all connectors are securely attached and free of corrosion

  6. 6. Test the Exhaust Pressure Sensor

    Use a multimeter to test the resistance of the exhaust pressure sensor. Compare the readings to the specifications provided in the service manual

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

  8. 8. Check for Vacuum Leaks

    Inspect the vacuum lines connected to the exhaust pressure sensor for any leaks or blockages. A vacuum leak can affect sensor readings

  9. 9. Inspect the Exhaust System

    Check the exhaust system for any blockages or restrictions that could affect exhaust pressure readings

  10. 10. Look for any signs of damage or leaks in the exhaust system

  11. 11. Test the Power and Ground Supply

    Verify that the exhaust pressure sensor is receiving the correct voltage and ground. Use a multimeter to check the voltage at the sensor connector

  12. 12. If there is no power or ground, trace the wiring back to the power source or ground point

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

    If all other components check out, there may be an issue with the ECM itself. Ensure that the ECM is functioning properly and that it is receiving the correct signals from the sensor

  14. 14. Clear Codes and Test Drive

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

  15. 15. Take the vehicle for a test drive to see if the code returns

  16. 16. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the exhaust pressure sensor or the specific vehicle model. Manufacturers may have issued updates or fixes for known issues.1

  17. 17. Seek Professional Help

    If you are unable to resolve the issue after these steps, consider seeking assistance from a qualified mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify the cause of the P047C code and take appropriate action to resolve it