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HOMESERVICE MANUALSFORD2021TRANSIT-350 HD BASE, VAN CARGO EXTENDED, 3.5L ENG VIN 8, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 13 (ENGINE CONTROLS - PINPOINT TESTS (DIESEL))PINPOINT TESTS RL: FUEL VAPORIZER SYSTEMTEST PROCEDURE
2021 Ford Transit-350 HD Base, Van Cargo Extended, 3.5L Eng VIN 8, AWD

Test Procedure

2021 Ford Transit-350 HD Base, Van Cargo Extended, 3.5L Eng VIN 8, AWDSECTION Test Procedure
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2018 Ford Transit-350 HD, 2018 Ford Transit-350, 2018 Ford Transit-250, 2018 Ford Transit-150, and 2018 Ford F-550 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
  1. RL1 PRELIMINARY DIAGNOSIS 

    Are DTCs P0420, P20CC, P20D7, P20D9, P20DA, P24A0, P2698, P269B, P269D, P269E or P26A0 present? 

    Yes No
    For DTCs P0420, P24A0, P269B, P269D, P269E or P26A0, GO to  RL2.
    For all others, GO to  RL10.    		 RETURN to SYMPTOM CHARTS for further direction.
  2. RL2 CHECK THE FUEL VAPORIZER SYSTEM GLOW PLUG RESISTANCE 
    • Ignition OFF.
    • Fuel Vaporizer System Glow Plug Assembly connector disconnected.
    • Measure the resistance between:
      (+) Fuel Vaporizer System Glow Plug Assembly Connector, Component Side (-) Fuel Vaporizer System Glow Plug Assembly Connector, Component Side
      VGPPWR - Pin 2 GND - Pin 1

    Is the resistance between 0 Ohm - 2 ohms? 

    Yes No
    GO to  RL3. INSTALL a new Fuel Vaporizer System Glow Plug assembly.
    REFER to the appropriate Exhaust System article.
    Clear the PCM DTCs. REPEAT the self-test.
  3. RL3 CHECK THE VPWR VOLTAGE TO THE FUEL VAPORIZER SYSTEM GLOW PLUG RELAY 
    • Ignition OFF.
    • Fuel Vaporizer System Glow Plug Relay connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side (-)
      VPWR - Pin 1, 3 Ground

    Is the voltage greater than 10.5 V? 

    Yes No
    GO to  RL4. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  4. RL4 CHECK THE FUEL VAPORIZER SYSTEM GLOW PLUG RELAY 
    • Carry out the fuel vaporizer system glow plug relay component test. Refer to the appropriate Wiring Diagrams, Component Testing article.

    Is a concern present? 

    Yes No
    INSTALL a new Fuel Vaporizer System Glow Plug relay. Clear the PCM DTCs. REPEAT the self-test. GO to  RL5.
  5. RL5 CHECK THE VGPRC CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • PCM-T connector disconnected.
    • Measure the resistance between:
      (+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side (-) PCM-T Connector, Harness Side
      VGPRC - Pin 2 VGPRC - Pin 28

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  RL6. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  6. RL6 CHECK THE VGPRC CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
      (+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side (-)
      VGPRC - Pin 2 Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  RL7. REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.
  7. RL7 CHECK THE VGPRC CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side (-)
      VGPRC - Pin 2 Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to  RL8.
  8. RL8 CHECK THE VGPPWR AND VGPRM CIRCUITS FOR AN OPEN 
    • Fuel Vaporizer System Glow Plug Relay connector disconnected.
    • Measure the resistance between:
      (+) Fuel Vaporizer System Glow Plug Assembly Connector, Harness Side (-) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side
      VGPPWR - Pin 2 VGPPWR - Pin 5
    • Measure the resistance between:
      (+) PCM-T Connector, Harness Side (-) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side
      VGPRM - Pin 26 VGPPWR - Pin 5

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  RL9. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  9. RL9 CHECK THE VGPPWR CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side (-)
      VGPPWR - Pin 5 Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. For DTC P0420, GO to  RA4.
    For DTC P24A0, GO to  RC11.
    For all others, INSTALL a new Fuel Vaporizer System Glow Plug assembly. REFER to the appropriate Exhaust System article.
    Clear the PCM DTCs. REPEAT the self-test.
  10. RL10 CHECK THE VPWR VOLTAGE TO THE FUEL VAPORIZER SYSTEM FUEL PUMP 
    • Ignition OFF.
    • Fuel Vaporizer System Fuel Pump Assembly connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Fuel Vaporizer System Fuel Pump Assembly Connector, Harness Side (-)
      VPWR - Pin 1 Ground

    Is the voltage greater than 10.5 V? 

    Yes No
    GO to  RL11. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  11. RL11 CHECK THE FUEL VAPORIZER SYSTEM FUEL PUMP RESISTANCE 
    • Ignition OFF.
    • Measure the resistance between:

    Is the resistance between 0 - 2 ohms? 

    (+) Fuel Vaporizer System Fuel Pump Assembly Connector, Component Side (-) Fuel Vaporizer System Fuel Pump Assembly Connector, Component Side
    VPWR - Pin 1 VPC - Pin 2
    Yes No
    GO to  RL12. INSTALL a new Fuel Vaporizer System Fuel Pump assembly. REFER to the appropriate Exhaust System article.
    Clear the PCM DTCs. REPEAT the self-test.
  12. RL12 CHECK THE VPC CIRCUIT FOR AN OPEN 
    • PCM-T connector connected.
    • Measure the resistance between:
      (+) Fuel Vaporizer System Fuel Pump Assembly Connector, Harness Side (-) PCM-T Connector, Harness Side
      VPC - Pin 2 VPC - Pin 2

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  RL13. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  13. RL13 CHECK THE VPC CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
      (+) Fuel Vaporizer System Fuel Pump Assembly Connector, Harness Side (-)
      VPC - Pin 2 Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  RL14. REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.
  14. RL14 CHECK THE VPC CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Fuel Vaporizer System Fuel Pump Assembly Connector, Harness Side (-)
      VPC - Pin 2 Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. INSTALL a new Fuel Vaporizer System Fuel Pump assembly. REFER to the appropriate Exhaust System article.
    Clear the PCM DTCs. REPEAT the self-test.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
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