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P code powertrain Medium severity

P20E6 Reductant Injection Air Pressure Too Low

The OBD2 code P20E6 indicates that the air pressure in the reductant injection system is too low, which can affect the proper functioning of the diesel exhaust fluid (DEF) injection process

Definition

The OBD2 code P20E6 indicates that the air pressure in the reductant injection system is too low, which can affect the proper functioning of the diesel exhaust fluid (DEF) injection process

Common causes

  • Faulty reductant pump
  • Clogged or damaged reductant lines
  • Defective pressure sensor
  • Leaks in the reductant system
  • Blocked or damaged air intake
  • Electrical issues (wiring or connectors)
  • Faulty control module
  • Low reductant fluid level

Common misdiagnoses

  • Faulty NOx sensor
  • Defective reductant pump
  • Clogged or damaged exhaust system
  • Low DEF (diesel exhaust fluid) level
  • Faulty wiring or connectors
  • Malfunctioning SCR (selective catalytic reduction) system
  • Air intake issues
  • Faulty pressure 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 Reductant System

  3. 3. Reductant Tank

    Ensure that the urea (DEF) tank is filled to the appropriate level. Low levels can cause pressure issues

  4. 4. Reductant Pump

    Check the operation of the reductant pump. Ensure it is functioning correctly and is not clogged or damaged

  5. 5. Reductant Lines

    Inspect the lines for any blockages, leaks, or damage that could affect pressure

  6. 6. Check the Air Pressure Sensor

    The air pressure sensor in the reductant system may be faulty. Test the sensor for proper operation and replace it if necessary

  7. 7. Inspect Electrical Connections

    Check all electrical connections related to the reductant system, including connectors and wiring. Look for corrosion, loose connections, or damaged wires

  8. 8. Check for Leaks

    Inspect the entire reductant system for any leaks that could cause a drop in pressure. Pay special attention to hoses, fittings, and the tank itself

  9. 9. Test the SCR System

    If applicable, test the SCR system components, including the catalyst and any associated sensors. A malfunctioning SCR system can lead to pressure issues

  10. 10. Clear the Code and Test Drive

    After performing any repairs or inspections, clear the trouble code using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  11. 11. Consult Technical Service Bulletins (TSBs)

    Check for any manufacturer-specific TSBs related to the P20E6 code. There may be known issues or recalls that could provide additional guidance

  12. 12. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized tools and knowledge to diagnose the problem more accurately. By following these steps, you can systematically identify and address the cause of the P20E6 code