WOMS
P code powertrain Medium severity

P20A0 Reductant Purge Control Valve Circuit /Open

The OBD2 code P20A0 indicates a malfunction in the reductant purge control valve circuit, specifically that the circuit is open, which means there is a break or fault in the electrical connection or the valve itself is...

Definition

The OBD2 code P20A0 indicates a malfunction in the reductant purge control valve circuit, specifically that the circuit is open, which means there is a break or fault in the electrical connection or the valve itself is not functioning properly

Common causes

  • Faulty reductant purge control valve
  • Open or shorted wiring in the circuit
  • Poor electrical connections
  • Failed engine control module (ECM)
  • Blocked or restricted reductant lines
  • Faulty sensors related to the reductant system

Common misdiagnoses

  • Faulty reductant pump
  • Defective NOx sensor
  • Malfunctioning engine control module (ECM)
  • Wiring issues or shorts in the harness
  • Clogged or contaminated diesel exhaust fluid (DEF)
  • Faulty reductant injector
  • Issues with the exhaust system or catalytic converter

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 Purge Control Valve

    Locate the reductant purge control valve and visually inspect it for any signs of damage, corrosion, or disconnection

  3. 3. Ensure that the valve is properly connected to its electrical connector

  4. 4. Test the Electrical Connections

    Check the wiring and connectors leading to the reductant purge control valve for any signs of wear, fraying, or corrosion

  5. 5. Use a multimeter to test for continuity in the wiring. An open circuit may indicate a broken wire or poor connection

  6. 6. Check the Reductant Purge Control Valve Operation

    If possible, manually test the valve by applying power to it to see if it opens and closes as expected

  7. 7. If the valve does not operate correctly, it may need to be replaced

  8. 8. Inspect the Reductant System

    Check the entire reductant system for leaks or blockages. This includes the lines, tank, and any associated components

  9. 9. Ensure that the reductant fluid (urea) is at the proper level and is not contaminated

  10. 10. Check the Power Supply

    Verify that the reductant purge control valve is receiving the correct voltage from the vehicle’s power supply. Use a multimeter to measure the voltage at the connector while the ignition is on

  11. 11. Examine the Engine Control Module (ECM)

    If all other components check out, there may be an issue with the ECM. Ensure that it is functioning properly and that there are no software issues

  12. 12. In some cases, a software update may be required

  13. 13. Clear the Codes and Test Drive

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

  14. 14. Take the vehicle for a test drive to see if the code returns. Monitor the system to ensure it operates correctly

  15. 15. Consult Technical Service Bulletins (TSBs)

    Check for any manufacturer-specific TSBs related to the P20A0 code. There may be known issues or recalls that could provide additional guidance

  16. 16. Seek Professional Help

    If you are unable to resolve the issue after these steps, consider seeking help from a qualified mechanic or dealership, especially if the problem persists. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P20A0 code