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P0473 Exhaust Pressure Sensor "A" Circuit High

The OBD2 code P0473 indicates that the exhaust pressure sensor "A" circuit is reading a high voltage signal, which may suggest a malfunction in the sensor or its circuit

Definition

The OBD2 code P0473 indicates that the exhaust pressure sensor "A" circuit is reading a high voltage signal, which may suggest a malfunction in the sensor or its circuit

Common causes

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

Common misdiagnoses

  • Faulty exhaust pressure sensor
  • Wiring issues or short circuits
  • Faulty turbocharger or wastegate
  • Exhaust leaks
  • Faulty engine control module (ECM)
  • Incorrectly calibrated or malfunctioning EGR system
  • Blocked or restricted exhaust system
  • Faulty vacuum lines or connections

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 more context and help identify related issues

  2. 2. Inspect the Exhaust Pressure Sensor

    Visual Inspection: Check the exhaust pressure sensor for any visible damage, corrosion, or loose connections

  3. 3. Wiring and Connectors

    Inspect the wiring harness and connectors for fraying, breaks, or poor connections. Ensure that the connectors are securely attached

  4. 4. Test the Exhaust Pressure Sensor

    Voltage and Ground: Use a multimeter to check the voltage supply and ground at the sensor connector. Compare the readings to the specifications in the vehicle’s service manual

  5. 5. Sensor Output

    Measure the output voltage of the sensor while the engine is running. The output should change with engine load and RPM. If it remains constant or is outside the expected range, the sensor may be faulty

  6. 6. Check for Blockages

    Inspect the exhaust system for any blockages or restrictions that could affect the exhaust pressure readings. This includes checking the DPF (Diesel Particulate Filter) if applicable

  7. 7. Inspect the Vacuum Lines (if applicable)

    If the exhaust pressure sensor is part of a system that uses vacuum lines, check for any leaks or blockages in the vacuum lines

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

    Ensure that the ECM is functioning properly. In rare cases, a faulty ECM can cause incorrect readings from the exhaust pressure sensor

  9. 9. Clear the Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner. Take the vehicle for a test drive to see if the code returns

  10. 10. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the P0473 code for your specific vehicle make and model. Manufacturers may have known issues or specific fixes

  11. 11. Seek Professional Help

    If you are unable to resolve the issue after these steps, consider seeking help from a professional mechanic who has experience with your vehicle type.Summary The P0473 code can be caused by a faulty exhaust pressure sensor, wiring issues, or exhaust system blockages. Following these troubleshooting steps can help you identify and fix the underlying problem. Always refer to the vehicle’s service manual for specific diagnostic procedures and specifications