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HOMESERVICE MANUALSFORD2007FUSION SEL, 2.3 Z, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1491 (ENGINE CONTROLS - PINPOINT TESTS (HYBRID))PINPOINT TEST DW: HEATED OXYGEN SENSOR (HO2S)TEST PROCEDURE
2007 Ford Fusion SEL, 2.3 Z, Standard

Test Procedure

2007 Ford Fusion SEL, 2.3 Z, StandardSECTION Test Procedure
WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, 2011 Ford Fusion, 2010 Mercury Milan, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
  1. DW1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) 

    Are any of the following DTCs present during PCM or transaxle control module (TCM) self-test: P0054, P0138, P013A, P013E, or P0141? 

    Yes No
    For DTC P0054, GO to  DW6.
    For DTC P0138, GO to  DW11.
    For DTCs P013A or P013E, GO to  DW16.
    For DTC P0141, GO to  DW2.    		 For all others, GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .
  2. DW2 DTC P0141: CHECK FOR A SOURCE OF POTENTIAL HO2S CONTAMINATION 
    • Ignition OFF.
    • Investigate the following items as potential sources of HO2S contamination:
      • use of unapproved silicon sealers
      • fuel contaminated by silicon additives
      • excessive oil burning (rings, valve seals, oil overfill)
      • glycol leaking internally in the engine
      • lead-contaminated fuel
      • short drive cycles in cold weather
      • use of unapproved cleaning agents

      Is a concern present? 

      Yes No
      REPAIR the source of the contamination.
      CHANGE the engine oil and oil filter. RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) . REPEAT the self-test.      		 GO to  DW3.
  3. DW3 VISUALLY INSPECT THE HO2S HARNESS 
    • PCM connector connected.
    • Visually inspect the HO2S harness for exposed wiring, water contamination, corrosion, and proper assembly.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to  DW4.
  4. DW4 CHECK THE HO2S AND SIGRTN CIRCUITS FOR AN OPEN IN THE HARNESS 
    NOTE: Verify the harness pins are in the proper location.
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) PCM Connector, Harness Side (-) HO2S Connector, Harness Side
    HO2S Signal - Pin T16 HO2S Signal - Pin 4
    SIGRTN - Pin E64 SIGRTN - Pin 3

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  DW5. REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.
  5. DW5 CARRY OUT THE KOEO ON DEMAND SELF-TEST 
    • Ignition ON, engine OFF.
    • Carry out the PCM KOEO self-test.

    Is DTC P0141 present? 

    Yes No
    GO to  DW6. GO to  DW7.
  6. DW6 DTC P0054: CHECK FOR VPWR IN THE HARNESS 
    • Ignition OFF.
    • HO2S connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    VOLTAGE REFERENCE CHART

    (+) HO2S Connector, Harness Side (-) HO2S Connector, Harness Side
    VPWR - Pin 1 SIGRTN - Pin 3

    Is the voltage greater than 10 V? 

    Yes No
    GO to  DW7. REPAIR the open circuit. CHECK the fuses.
    Clear the PCM DTCs. REPEAT the self-test.
  7. DW7 CHECK THE HO2S HEATER FOR SHORTS IN THE HARNESS 
    • Ignition OFF.
    • HO2S connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) HO2S Connector, Harness Side (-) Vehicle Battery
      HO2S Heater - Pin 2 Negative terminal
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) HO2S Connector, Harness Side (-) HO2S Connector, Harness Side
    HO2S Heater - Pin 2 VPWR - Pin 1
    HO2S Heater - Pin 2 SIGRTN - Pin 3
    HO2S Heater - Pin 2 HO2S Signal - Pin 4

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to  DW8. REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.
  8. DW8 CHECK THE HO2S HEATER CIRCUIT FOR AN OPEN IN THE HARNESS 
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) PCM Connector, Harness Side (-) HO2S Connector, Harness Side
    HO2S Heater - Pin T18 HO2S Heater - Pin 2

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  DW9. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  9. DW9 CHECK THE INTERNAL RESISTANCE OF THE HO2S HEATER 
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) HO2S Connector, Component Side (-) HO2S Connector, Component Side
    VPWR - Pin 1 HO2S Heater - Pin 2

    Is the resistance between 3 - 30 ohms? 

    Yes No
    GO to  DW10. INSTALL a new HO2S. REFER to the ELECTRONIC ENGINE CONTROLS (HYBRID) RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) . REPEAT the self-test.
  10. DW10 CHECK THE HO2S HEATER CIRCUIT FOR AN INTERNAL SHORT TO SIGRTN OR GND 
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) HO2S Connector, Component Side (-) HO2S Connector, Component Side
      HO2S Heater - Pin 2 SIGRTN - Pin 3
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) HO2S Connector, Component Side (-) Vehicle Battery
    HO2S Heater - Pin 2 Negative terminal

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  DW19. INSTALL a new HO2S. REFER to the ELECTRONIC ENGINE CONTROLS (HYBRID) RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
  11. DW11 DTC P0138: VISUALLY INSPECT THE HO2S HARNESS 
    • Ignition OFF.
    • HO2S connector disconnected.
    • Visually inspect the HO2S harness.
    • Check the connector (both halves) for any water contamination.
    • Make sure the connector pins are fully seated.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to  DW12.
  12. DW12 CHECK THE HO2S SIGNAL LEVEL TOO HIGH 
    • HO2S connector connected.
    • Ignition ON, engine running.
    • Access the PCM and monitor the O2S12 (VOLT) PID.

    Is the voltage less than 1.1 V? 

    Yes No
    GO to  DW13. GO to  DW14.
  13. DW13 CARRY OUT A THOROUGH WIGGLE TEST ON THE HO2S HARNESS 
    • Ignition OFF.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the O2S12 (VOLT) PID.
    • Carry out a thorough wiggle test on the HO2S harness.

    Does the voltage change during the wiggle test? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to PINPOINT TEST Z .
  14. DW14 CHECK THE HO2S SIGNAL FOR A SHORT TO VPWR INSIDE THE SENSOR 
    • Ignition OFF.
    • HO2S connector disconnected.
    • Ignition ON, engine running.
    • Access the PCM and monitor the O2S12 (VOLT) PID.

    Is the voltage less than 1.1 V? 

    Yes No
    INSTALL a new HO2S. REFER to the ELECTRONIC ENGINE CONTROLS (HYBRID) RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) . REPEAT the self-test. GO to  DW15.
  15. DW15 CHECK THE HO2S CIRCUIT FOR A SHORT TO VPWR IN THE HARNESS 
    • Ignition OFF.
    • PCM connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    VOLTAGE REFERENCE CHART

    (+) HO2S Connector, Harness Side (-)
    HO2S Signal - Pin 4 Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to  DW19.
  16. DW16 DTC P013A, P013E: CHECK FOR OTHER SELF-TEST DTCS 

    Are any DTCs present other than P013A or P013E? 

    Yes No
    DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS . GO to  DW17.
  17. DW17 CHECK FOR EXHAUST SYSTEM AND FUEL SELECTION CONCERNS 
    • Inspect the exhaust system for the following:
      • leaks, cracks, or punctures
      • aftermarket accessories and performance modifications
      • exhaust leaks at the HO2S
    • Verify with the customer that flex fuel is not being used on this vehicle.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For DTC P013A, INSTALL a new HO2S. REFER to the ELECTRONIC ENGINE CONTROLS (HYBRID) RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    For all others, GO to  DW18.
  18. DW18 CHECK FOR AN INTERMITTENT HO2S SIGNAL 
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the O2S12 (VOLT) PID.
    • Wiggle, shake, and bend small sections of the wiring harness while working from the sensor to the PCM.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 INSTALL a new HO2S. REFER to the ELECTRONIC ENGINE CONTROLS (HYBRID) RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
  19. DW19 CHECK FOR CORRECT PCM OPERATION 
    • Disconnect all the PCM connectors.
    • Visually inspect for:
      • pushed out pins
      • corrosion
    • Connect all the PCM connectors and make sure they seat correctly.
    • Carry out the PCM self-test.
    • Verify the concern is still present.

    Is the concern still present? 

    Yes No
    INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) , PROGRAMMING THE VID BLOCK FOR A REPLACEMENT PCM . The system is operating correctly at this time.
    The concern may have been caused by a loose or corroded connector.
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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.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.