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P20E7 Reductant Injection Air Pressure Too High

The OBD2 code P20E7 indicates that the air pressure in the reductant injection system is too high, which can affect the proper functioning of the diesel exhaust fluid (DEF) injection process

Definition

The OBD2 code P20E7 indicates that the air pressure in the reductant injection system is too high, which can affect the proper functioning of the diesel exhaust fluid (DEF) injection process

Common causes

  • Faulty reductant pump
  • Blocked or restricted reductant lines
  • Malfunctioning pressure sensor
  • Leaks in the reductant system
  • Electrical issues or wiring problems
  • Defective reductant injector
  • Contaminated reductant fluid

Common misdiagnoses

  • Faulty NOx sensor
  • Defective reductant pump
  • Clogged or damaged exhaust system
  • Faulty pressure sensor
  • Wiring issues or short circuits
  • Defective SCR (Selective Catalytic Reduction) system
  • Incorrectly calibrated fuel system
  • Air intake issues

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. Hoses and Connections

    Inspect all hoses and connections in the reductant system for any signs of damage, leaks, or blockages

  4. 4. Reductant Injector

    Check the reductant injector for proper operation. Ensure it is not clogged or malfunctioning

  5. 5. Check the Reductant Tank

  6. 6. Ensure that the reductant (urea) level is adequate. Low levels can sometimes cause pressure issues

  7. 7. Inspect the tank for any signs of contamination or crystallization of the urea

  8. 8. Inspect the Pressure Sensor

  9. 9. The pressure sensor in the reductant system may be faulty. Check the sensor for proper operation and ensure that it is not damaged or clogged

  10. 10. Test the electrical connections to the sensor for any signs of corrosion or loose connections

  11. 11. Check for Blockages

  12. 12. Inspect the exhaust system for any blockages that could affect the SCR system's operation

  13. 13. Ensure that the SCR catalyst is not clogged or damaged

  14. 14. Examine the Air Intake System

  15. 15. Check the air intake system for any restrictions or leaks that could affect the air pressure readings

  16. 16. Test the SCR System

  17. 17. If equipped, perform a functional test of the SCR system to ensure it is operating correctly

  18. 18. Check for any software updates or recalls related to the SCR system from the manufacturer

  19. 19. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes and take the vehicle for a test drive to see if the code returns

  20. 20. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the P20E7 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues

  21. 21. Professional Diagnosis

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with diesel engines and SCR systems. By following these troubleshooting steps, you can identify and potentially resolve the issue associated with the P20E7 code