LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 2005 >> Excursion 6.0 P, 4WD >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Pinpoint Tests - 6.0L Diesel (99P F450/550) >> Pinpoint Test M: Pinpoint Test M: Fuel Pump Monitor/Control >> Test Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Procedure

  1. M1 PRELIMINARY DIAGNOSIS FOR DTCS P0230, P0231, AND P0232 
    NOTE: For F-Super Duty/Excursion, the fuel pump relay is internal to the central junction box (CJB).
    • Retrieve and record all DTCs.
    • Record the freeze frame data.
    • Clear the DTCs.
    • Carry out the on-demand self-test.

    Are any DTCs retrieved? 

    Yes No
    For DTC P0230 (F-Super Duty/Excursion), GO to  M2.
    For DTC P0230 (E-Series), GO to  M3.
    For P0231, GO to  M8.
    For P0232, GO to  M14.    		 UNABLE to duplicate the condition. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the fault. REPAIR as necessary. REFER to SYMPTOM CHARTS - 6.0L DIESEL if a driveability concern exists.
  2. M2 DIAGNOSTIC TROUBLE CODE (DTC) P0230 
    • Possible causes:
      • fuel pump relay (internal to CJB)
      • circuitry
      • PCM
    • Key OFF.
    • Disconnect CJB C270f.
    • Key ON, engine OFF.
    • Measure the voltage between CJB C270f pin 10, component side and ground.

    Is the voltage greater than 10.5 volts? 

    Yes No
    GO to  M5. INSTALL a new CJB. CLEAR the DTCs. REPEAT the self-test.
  3. M3 CHECK THE FUEL PUMP RELAY VOLTAGE CIRCUIT 
    NOTE: Refer to SYSTEM WIRING DIAGRAMS for the fuel pump relay coil pin locations.
    • Possible causes:
      • fuel pump relay
      • circuitry
      • PCM
    • Key OFF.
    • Disconnect the fuel pump relay.
    • Key ON, engine OFF.
    • Measure the voltage between the fuel pump relay coil power circuit, harness side and ground.

    Is the voltage greater than 10.5 volts? 

    Yes No
    GO to  M4. REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  4. M4 CHECK THE FUEL PUMP RELAY 
    • Carry out the fuel pump relay component test. Refer to COMPONENT TESTING .

    Does the fuel pump relay pass the component test? 

    Yes No
    GO to  M5. INSTALL a new fuel pump relay. CLEAR the DTCs. REPEAT the self-test.
  5. M5 CHECK THE FUEL PUMP RELAY CONTROL CIRCUIT FOR AN OPEN 
    NOTE: Refer to SYSTEM WIRING DIAGRAMS for fuel pump relay coil pin locations.
    • Key OFF.
    • Disconnect the PCM body harness connector.
    • Measure the resistance between the CJB C270f pin 10 (F-Super Duty/Excursion) or the fuel pump relay coil control circuit (E-Series), harness side and the PCM body harness connector pin 5, harness side.

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  M6. REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  6. M6 CHECK THE FUEL PUMP RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between the PCM body harness connector pin 5, harness side and ground.

    Is the resistance greater than 10,000 ohms? 

    Yes No
    GO to  M7, REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  7. M7 CHECK THE FUEL PUMP RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE 
    • Key ON, engine OFF.
    • Measure the voltage between the PCM body harness connector pin 5, harness side and ground.

    Is any voltage indicated? 

    Yes No
    REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. INSTALL a new PCM. CLEAR the DTCs. REPEAT the self-test.
  8. M8 DIAGNOSTIC TROUBLE CODE (DTC) P0231 
    NOTE: Diagnose and repair DTC P0230 before addressing DTC P0231.
    • Possible causes:
      • inertia switch
      • fuel pump monitor circuit open
      • fuel pump relay
    • Key OFF.
    • Disconnect the inertia switch.
    • Measure the resistance between the inertia switch pin 1, component side and the inertia switch pin 3 (F-Super Duty/Excursion) or pin 2 (E-Series), component side.

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  M9. INSTALL a new inertia switch. CLEAR the DTCs. REPEAT the self-test.
  9. M9 CHECK THE FUEL PUMP VOLTAGE 
    • Connect a test lamp between the inertia switch pin 1 (F-Super Duty/Excursion) or pin 2 (E-Series), harness side and ground.
    • Key ON, engine OFF.

    Does the test lamp illuminate for approximately 20 seconds? 

    Yes No
    GO to  M13. For F-Super Duty/Excursion, GO to  M10.
    For E-Series, GO to  M11.
  10. M10 CHECK THE FUEL PUMP VOLTAGE CIRCUIT FOR AN OPEN 
    • Key OFF.
    • Disconnect CJB C270a.
    • Measure the resistance between CJB C270a pin 22, harness side and the inertia switch pin 1, harness side.

    Is the resistance less than 5 ohms? 

    Yes No
    INSTALL a new CJB. CLEAR the DTCs. REPEAT the self-test. REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  11. M11 CHECK THE FUEL PUMP RELAY POWER CIRCUIT FOR VOLTAGE 
    • Key OFF.
    • Disconnect the fuel pump relay.
    • Key ON, engine OFF.
    • Measure the voltage between the fuel pump relay power circuit pin 30, harness side and ground.

    Is the voltage greater than 10.5 volts? 

    Yes No
    GO to  M12. REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  12. M12 CHECK THE FUEL PUMP RELAY 
    • Carry out the fuel pump relay component test. Refer to COMPONENT TESTING .

    Does the fuel pump relay pass the component test? 

    Yes No
    REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. INSTALL a new fuel pump relay. CLEAR the DTCs. REPEAT the self-test.
  13. M13 CHECK THE FUEL PUMP MONITOR CIRCUIT FOR AN OPEN 
    • Key OFF.
    • Disconnect the PCM.
    • Measure the resistance between the inertia switch pin 3 (F-Super Duty/Excursion) or pin 1 (E-Series), harness side and the PCM body harness connector pin 19, harness side.

    Is the resistance less than 5 ohms? 

    Yes No
    INSTALL a new PCM. CLEAR the DTCs. REPEAT the self-test. REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  14. M14 DIAGNOSTIC TROUBLE CODE (DTC) P0232 
    NOTE: Diagnose and repair DTC P0230 before addressing DTC P0232.
    • Possible causes:
      • fuel pump relay
      • fuel pump monitor circuit open or short to voltage
      • fuel pump ground circuit open
      • fuel pump
    • Key off.
    • Disconnect central junction box (CJB) C270a (F-Super Duty/Excursion).
    • Disconnect the fuel pump relay (E-Series).
    • Key on, engine off.

    Is the fuel pump on? 

    Yes No
    GO to  M15. GO to  M16.
  15. M15 CHECK THE FUEL PUMP MONITOR CIRCUIT FOR A SHORT TO VOLTAGE 
    • Key off.
    • Disconnect the PCM body harness connector.
    • Disconnect the fuel pump.
    • Key on, engine off.
    • Measure the voltage between the PCM body harness connector pin 19, harness side and ground.

    Is any voltage indicated? 

    Yes No
    REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CLEAR the DTCs. REPEAT the self-test. If the DTC P0232 is present again, INSTALL a new PCM.
  16. M16 CHECK THE FUEL PUMP GROUND FOR AN OPEN 
    • Key off.
    • Disconnect the fuel pump.
    • Measure the resistance between the fuel pump ground pin 2, harness side and ground.

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  M17. REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  17. M17 CHECK THE FUEL PUMP 
    • Measure the resistance between the fuel pump pin 1, component side and the fuel pump pin 2, component side.

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  M18. INSTALL a new fuel pump. CLEAR the DTCs. REPEAT the self-test.
  18. M18 CHECK THE FUEL PUMP MONITOR CIRCUIT AN OPEN 
    • Disconnect the PCM body harness connector.
    • Measure the resistance between the PCM body harness connector pin 19, harness side and the fuel pump pin 1, harness side.

    Is the resistance less than 5 ohms? 

    Yes No
    For E-Series, GO to  M19.
    For F-Super Duty/Excursion, GO to  M20.    		 REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  19. M19 CHECK THE FUEL PUMP RELAY 
    • Carry out the fuel pump relay component test. Refer to COMPONENT TESTING .

    Does the fuel pump relay pass the component test? 

    Yes No
    CLEAR the DTCs and RETEST the system. If the DTC P0232 is present again, INSTALL a new PCM. INSTALL a new fuel pump relay. CLEAR the DTCs. REPEAT the self-test.
  20. M20 CHECK THE CJB FUEL PUMP RELAY 
    • Connect CJB C270a.
    • Connect a 5-amp fused jumper wire between the PCM body connector pin 5 harness side, and ground.
    • Measure the voltage between the PCM body connector pin 19 harness side, and ground.
    • Key on, engine off.

    Is the voltage greater than 10 volts with the jumper installed and less than 1 volt with the jumper removed? 

    Yes No
    CLEAR the DTCs. REPEAT the self-test. If DTC P0232 is present again, INSTALL a new PCM. INSTALL a new CJB. CLEAR the DTCs. REPEAT the self-test.
scientia non olet · About LEMON Manuals