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Home >> Ford >> 2015 >> Explorer Limited, 3.5L Eng VIN 8, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls (Except Diesel & Hybrid) - Pinpoint Tests DN - FD >> Pinpoint Test DZ: Universal Heated Oxygen Sensor (HO2S) >> Test Procedure

Test Procedure

  1. DZ1 CHECK FOR DTCS 

    Are DTCs P0030, P0040, P0050, P0053, P0059, P0130, P0131, P0132, P0133, P0134, P0135, P0150, P0151, P0152, P0153, P0154, P0155, P1127, P164A, P164B, P2096, P2097, P2098, P2099, P2237, P2240, P2243, P2247, P2251, P2254, P2626, P2627, P2628, P2629, P2630, or P2631 present? 

    Yes No
    For DTC P0040, GO to  DZ6.
    For DTC P1127, GO to  DZ17.
    For DTCs P0133, P0153, P2096, P2097, P2098 or P2099, GO to  DZ18.
    For DTCs P164A, P164B, P2626, P2627, P2628, P2629, P2630 or P2631, GO to  DZ23.
    For all others, GO to DZ2  .    		 For Escape/Kuga 2.5L, Fusion 2.5L or Transit Connect 2.5L symptoms without DTCs, GO to  DZ12.
    For all other vehicles symptoms without DTCs, GO to  DZ23.
    For all others, RETURN to SYMPTOM CHARTS for further direction.
  2. DZ2 VISUALLY INSPECT THE UNIVERSAL HO2S HARNESS 
    • Ignition OFF.
    • Visually inspect for:
      • pinched, shorted, and corroded wiring and pins
      • oil or water contamination
      • crossed sensor wires
      • damaged universal HO2S

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For DTCs P0030 or P0050, GO to DZ3  .
    For DTCs P0053, P0059, P0135 or P0155, GO to  DZ7.
    For DTCs P0130, P0131, P0132, P0150, P0151, P0152, P2243, P2247, P2251 or P2254, GO to  DZ12.
    For all others, GO to  DZ16.
  3. DZ3 CHECK FOR MISFIRE CONCERNS AND AFTERMARKET EQUIPMENT 
    • Ignition OFF.
    • Check for the following:
      • misfire concern
      • non-factory or aftermarket equipment that may increase the exhaust temperature
    • Universal HO2S connector disconnected.
    • Check the universal HO2S connector for damage or corrosion.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to DZ4  .
  4. DZ4 CHECK THE UO2SHTR CIRCUIT FOR A SHORT TO VOLTAGE 
    • PCM connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Universal HO2S Connector, Harness Side (-)
      UO2SHTR Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.    		 GO to DZ5  .
  5. DZ5 CHECK THE UO2S, UO2SGREF, UO2SHTR CIRCUITS FOR AN OPEN 
    • Ignition OFF.
    • Measure the resistance between:
      (+) Universal HO2S Connector, Harness Side (-) PCM Connector, Harness Side
      UO2S UO2S
      UO2SGREF UO2SGREF
      UO2SHTR UO2SHTR

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  DZ7. REPAIR the open circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  6. DZ6 CROSSED SENSOR WIRES 
    • Ignition OFF.
    • Check the vehicle repair history.
    • Verify the connectors are connected to the correct engine bank.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 Unable to duplicate or identify the concern at this time.
    GO to PINPOINT TEST Z .
  7. DZ7 CHECK FOR VPWR 
    • Ignition OFF.
    • Universal HO2S connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Universal HO2S Connector, Harness Side (-)
      VPWR Ground

    Is the voltage greater than 10.5 V? 

    Yes No
    GO to DZ8  . REPAIR the open circuit. CHECK the fuses.
    Clear the PCM DTCs. REPEAT the self-test.
  8. DZ8 CHECK THE UO2SHTR CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Universal HO2S connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) Universal HO2S Connector, Harness Side (-) PCM Connector, Harness Side
      UO2SHTR UO2SHTR

    Is the resistance less than 5 ohms? 

    Yes No
    GO to DZ9  . REPAIR the open circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  9. DZ9 CHECK THE UO2SHTR CIRCUIT FOR A SHORT 
    NOTE: This pinpoint test is designed to diagnose multiple circuits in the same test steps, only measure the circuits that apply to the vehicle being diagnosed.
    • Measure the resistance between:
      (+) Universal HO2S Connector, Harness Side (-)
      UO2SHTR Ground
    • Measure the resistance between:
      (+) Universal HO2S Connector, Harness Side (-) Universal HO2S Connector, Harness Side
      UO2SHTR UO2S
      UO2SHTR UO2SGREF
      UO2SHTR UO2SPC
      UO2SHTR UO2SPCT
      UO2SHTR VPWR

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to DZ10  . REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  10. DZ10 CHECK THE INTERNAL RESISTANCE OF THE UNIVERSAL HO2S HEATER 
    • Measure the resistance between:
      (+) Universal HO2S Connector, Component Side (-) Universal HO2S Connector, Component Side
      VPWR UO2SHTR

    Is the resistance between 1.8 - 6 ohms? 

    Yes No
    GO to DZ11  . INSTALL a new Universal HO2S. REFER to the service information , Electronic Engine Controls.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.
  11. DZ11 CHECK THE UO2SHTR CIRCUIT FOR AN INTERNAL SHORT TO GROUND 
    • Measure the resistance between:
      (+) Universal HO2S Connector, Component Side (-)
      UO2SHTR Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    For DTCs P0030 or P0050, GO to DZ12  .
    For all others, GO to  DZ28.    		 INSTALL a new Universal HO2S. REFER to the service information , Electronic Engine Controls.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.
  12. DZ12 CHECK THE UO2S AND UO2SGREF CIRCUITS FOR AN OPEN 
    • Ignition OFF.
    • Universal HO2S connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) Universal HO2S Connector, Harness Side (-) PCM Connector, Harness Side
      UO2S UO2S
      UO2SGREF UO2SGREF

    Are the resistances less than 5 ohms? 

    Yes No
    GO to DZ13  . REPAIR the open circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  13. DZ13 CHECK THE UO2S, UO2SGREF, UO2SPC, AND UO2SPCT CIRCUITS FOR A SHORT TO GROUND 
    NOTE: This pinpoint test is designed to diagnose multiple circuits in the same test steps, only measure the circuits that apply to the vehicle being diagnosed.
    • Measure the resistance between:
      (+) Universal HO2S Connector, Harness Side (-)
      UO2S Ground
      UO2SGREF Ground
      UO2SPC Ground
      UO2SPCT Ground

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to DZ14  . REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  14. DZ14 CHECK THE UO2S, UO2SGREF, UO2SPC, AND UO2SPCT CIRCUITS FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Universal HO2S Connector, Harness Side (-)
      UO2S Ground
      UO2SGREF Ground
      UO2SPC Ground
      UO2SPCT Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.    		 GO to DZ15  .
  15. DZ15 CHECK THE UO2SGREF CIRCUIT FOR VOLTAGE 
    • Ignition OFF.
    • PCM connector connected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Universal HO2S Connector, Harness Side (-)
      UO2SGREF Ground

      Universal HO2S UO2SGREF Circuit Voltage 

      Vehicle Voltage
      E-Series 6.8L, F-650/F-750, F-Series Super Duty 2 - 2.4
      E-Series 5.4L, Edge 2.0L, Edge 2.7L, Escape/Kuga 1.6L, Escape/Kuga 2.0L, Expedition, Explorer 2.0L, Explorer GTDI 3.5L, F-150 2.7L, F-150 3.5L GTDI, Fiesta, Flex GTDI 3.5L, Focus, Fusion 1.5L, Fusion 1.6L, Fusion 2.0L, MKC, MKS 3.5L, MKT 2.0L, MKT 3.5L, MKZ 2.0L, Mustang 2.3L, Navigator, Taurus 2.0L, Taurus GTDI 3.5L, Transit 3.5L, Transit Connect 1.6L 2.4 - 2.6
      F-150 3.5L TiVCT, F-150 5.0L, Mustang 5.0L 2.3 - 2.5
      All others 3.5 - 3.7

    Is the voltage within specification? 

    Yes No
    INSTALL a new Universal HO2S. REFER to the service information , Electronic Engine Controls.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.    		 For Escape/Kuga 2.5L, Fusion 2.5L or Transit Connect 2.5L symptoms without DTCs, RETURN to SYMPTOM CHARTS for further direction.
    For all others, GO to  DZ28.
  16. DZ16 CHECK THE UO2SPC CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Universal HO2S connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) Universal HO2S Connector, Harness Side (-) PCM Connector, Harness Side
      UO2SPC UO2SPC

    Is the resistance less than 5 ohms? 

    Yes No
    INSTALL a new Universal HO2S. REFER to the service information , Electronic Engine Controls.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .    		 REPAIR the open circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  17. DZ17 EXHAUST TEMPERATURE OUT OF RANGE 
    NOTE: Diagnose all other powertrain related DTCs first.
    • Ignition ON, engine running.
    • Engine at normal operating temperature.
    • Access the PCM and monitor the HTR11 (MODE) and HTR21 (MODE) PIDs.

    Are the PID states ON? 

    Yes No
    CARRY OUT the KOER self-test. RUN the engine until the PID indicates ON.
    CARRY OUT the KOER self-test.
  18. DZ18 CARRY OUT THE KOER SELF-TEST 
    • Engine at normal operating temperature.
    • Carry out the PCM KOER self-test.

    Are any DTCs present other than P0133, P0153, P2096, P2097, P2098, or P2099? 

    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 . For DTCs P0133 or P0153, GO to  DZ21.
    For all others, GO to DZ19  .
  19. DZ19 VISUALLY INSPECT THE UPSTREAM AND DOWNSTREAM HO2S CONNECTORS 
    • Ignition OFF.
    • Universal HO2S connector disconnected.
    • HO2S12 connector disconnected.
    • HO2S22 connector disconnected.
    • Check for a loose connection and damaged or corroded terminals.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) . REPEAT the self-test.    		 GO to DZ20  .
  20. DZ20 CHECK FOR LEAKS IN THE EXHAUST SYSTEM 
    • Visually inspect the exhaust system for the following:
      • exhaust leaks at flanges and gaskets
      • HO2S not tightened to specification
      • physical exhaust system concerns
      • aftermarket exhaust
      • punctures or cracks in the catalytic converter

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) . REPEAT the self-test.    		 GO to DZ21  .
  21. DZ21 CHECK FOR POTENTIAL SENSOR CONTAMINATION CONCERNS 
    • Investigate the following items as potential sources of universal HO2S contamination:
      • use of unapproved silicon sealers
      • fuel contaminated by silicon additives
      • excessive oil consumption
      • 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.
    INSTALL a new Universal HO2S. REFER to the service information , Electronic Engine Controls.
    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.    		 For DTCs P0133 or P0153, GO to DZ22  .
    For all others, INSTALL a new Universal HO2S. REFER to the service information , Electronic Engine Controls.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) . REPEAT the self-test.
  22. DZ22 CHECK THE UNIVERSAL HO2S RESPONSE TEST RESULTS 

    Is the indicated value greater than the minimum threshold? 

    Yes No
    Unable to duplicate or identify the concern at this time.
    Clear the PCM DTCs. REPEAT the self-test.    		 INSTALL a new Universal HO2S. REFER to the service information , Electronic Engine Controls.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.
  23. DZ23 CHECK THE UO2SPCT CIRCUIT FOR AN OPEN CIRCUIT 
    • Ignition OFF.
    • Universal HO2S connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) Universal HO2S Connector, Harness Side (-) PCM Connector, Harness Side
      UO2SPCT UO2SPCT

    Is the resistance less than 5 ohms? 

    Yes No
    For DTC P2626 or P2629 or symptoms without DTCs, GO to  DZ27.
    For all others, GO to DZ24  .    		 REPAIR the open circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  24. DZ24 CHECK THE UO2SPCT CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
      (+) PCM Connector, Harness Side (-)
      UO2SPCT Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to DZ25  . REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  25. DZ25 CHECK THE UO2SPCT CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Universal HO2S Connector, Harness Side (-)
      UO2SPCT Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.    		 GO to DZ26  .
  26. DZ26 CHECK THE RESISTANCE OF THE LABEL RESISTOR IN THE UNIVERSAL HO2S 
    • Measure the resistance between:
      (+) Universal HO2S Connector, Component Side (-) Universal HO2S Connector, Component Side
      UO2SPCT VPWR

    Is the resistance between 3.5K - 999.9K ohms? 

    Yes No
    For DTCs P164A or P164B, unable to duplicate or identify the concern at this time.
    GO to PINPOINT TEST Z .
    For DTCs P2627, P2628, P2630 or P2631, GO to  DZ28.    		 INSTALL a new Universal HO2S.
    REFER to the service information , Electronic Engine Controls.
    RESET the keep alive memory (KAM), REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.
  27. DZ27 CHECK THE RESISTANCE OF THE CURRENT TRIM RESISTOR IN THE UNIVERSAL HO2S 
    • Measure the resistance between:
      (+) Universal HO2S Connector, Component Side (-) Universal HO2S Connector, Component Side
      UO2SPCT UO2SPC

    Is the resistance between 25 - 330 ohms? 

    Yes No
    For DTCs P2626 or P2629, GO to DZ28  .
    For all others, RETURN to NO DIAGNOSTIC TROUBLE CODES (DTCS) PRESENT SYMPTOM CHART INDEX for further direction.    		 INSTALL a new Universal HO2S. REFER to the service information , Electronic Engine Controls.
    RESET the keep alive memory (KAM), REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.
  28. DZ28 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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