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Home › Ford › 2020 › Escape Titanium Plug-In Hybrid › Repair and Diagnosis › Engine Performance › System › Engine Controls - Pinpoint Tests (Hybrid) › Pinpoint Tests DW: Heated Oxygen Sensor (Ho2S) › Test Procedure

Test Procedure

  1. DW1 CHECK FOR DTCS 

    Are DTCs P0054, P0137, P0138, P013A, P013E or P0141 present? 

    Yes No
    For DTC P013A, GO to  DW5.
    For all others, GO to  DW2.    		 RETURN to SYMPTOM CHARTS for further direction.
  2. DW2 VISUALLY INSPECT THE HO2S HARNESS 
    • Ignition OFF.
    • Verify the HO2S connectors are connected to the correct engine bank.
    • Visually inspect for:
      • crossed sensor wires
      • pinched, shorted, and corroded wiring and pins
      • oil or water contamination
      • damaged HO2S

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For DTC P013E, GO to  DW5.
    For DTC P0137, GO to  DW6.
    For all others, GO to  DW3.
  3. DW3 CHECK FOR A SOURCE OF POTENTIAL HO2S CONTAMINATION 
    • Investigate the following items as potential sources of HO2S contamination:
      • use of unapproved silicon sealers
      • fuel contaminated by silicon additives
      • excessive oil consumption
      • glycol leaking internally in the engine
      • 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) , Programming the VID Block for a Replacement PCM.
    REPEAT the self-test.    		 GO to  DW4.
  4. DW4 CHECK FOR UNMETERED AIR LEAKS 
    NOTE: Fuel calculations can be affected by unmetered air leaks.
    • Carefully inspect the following areas for potential air leaks:
      • hoses connecting to the mass airflow (MAF) sensor assembly
      • hoses connecting to the throttle body
      • intake manifold gasket leaks
      • positive crankcase ventilation (PCV) system
      • the vacuum lines are disconnected
      • incorrectly seated engine oil dipstick, tube or oil fill cap

    Are any air leaks present? 

    Yes No
    REPAIR the source of the air leak. RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) , Programming the VID Block for a Replacement PCM.
    REPEAT the self-test.    		 GO to  DW5.
  5. DW5 CHECK FOR EXHAUST SYSTEM CONCERNS 
    NOTE: Pressure above 241 kPa (35 psi) can cause damage to system components. Regulate the shop air to 34.4 - 68.9 kPa (5 - 10 psi) before connecting to the system.
    NOTE: Remember to remove the plastic bag from the air filter at the completion of this step.
    NOTE: The DTCs P013A and P013E refer to the HO2S12 sensor that is located after the catalyst. Before installing a new HO2S12 sensor, refer to the 4 pin HO2S sensor connector view at the beginning of this pinpoint test to verify the correct HO2S sensor replacement.
    • Place the air filter in a plastic bag to prevent air flow out of the intake port and reinstall it in the vehicle.
    • Pressurize the exhaust system at the exhaust pipe outlet with 34.4 - 68.9 kPa (5 - 10 psi) regulated shop air.
    • Check the exhaust system for leaks using a soap and water solution.
    • Apply the soap and water solution to the following areas:
      • the exhaust flanges and gaskets
      • the universal HO2S and mounting surface
      • the exhaust system in between the universal HO2S and the downstream HO2S
      • the downstream HO2S and mounting surface
      • the exhaust system within 15.25 cm (6 inches) of the downstream HO2S and mounting surface
    • Check the exhaust flange bolts for correct torque.
    • Check the downstream HO2S for correct torque.

    Is a concern present? 

    Yes No
    For DTCs P013A or P013E, REPAIR as necessary.
    CARRY OUT the HO2S and Catalyst OBD Monitor Drive Cycle Procedures. REFER to ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE .
    Clear the PCM DTCs. REPEAT the self-test.
    For all others, REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For DTCs P013A or P013E, INSTALL a new HO2S. REFER to the Electronic Engine Controls article.
    CARRY OUT the HO2S and Catalyst OBD Monitor Drive Cycle Procedures. REFER to ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE .
    Clear the PCM DTCs. REPEAT the self-test.
    For all others, GO to  DW6.
  6. DW6 CHECK THE SENSOR 
    NOTE: The HO2S heater must be ON for 2 minutes before continuing diagnosis.
    • Ignition ON, engine running.
    • Allow the engine to idle until the HO2S heater PID indicates ON for 2 minutes.
    • Access the PCM and monitor the HTR12 (MODE) PID.
    • Access the PCM and control the EQRAT11_DSD (RATIO) PID.
    • Command the PID to 13:1.
    • Access the PCM and monitor the O2S12 (VOLT) PID.
    • Record the PID value.

    Is the PID voltage approximately 0.8V? 

    Yes No
    GO to  DW7. GO to  DW8.
  7. DW7 CARRY OUT A THOROUGH WIGGLE TEST ON THE HO2S HARNESS 
    NOTE: The HO2S heater must be ON for 2 minutes before continuing diagnosis.
    • Access the PCM and monitor the HTR12 (MODE) PID.
    • Access the PCM and control the EQRAT11_DSD (RATIO) PID.
    • Command the PID to 13:1.
    • Access the PCM and monitor the O2S12 (VOLT) PID.
    • Carry out a thorough wiggle test on the HO2S12 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 .
  8. DW8 CHECK FOR VPWR 
    • HO2S connector disconnected.
    • Check both halves of the connector for any water contamination.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) HO2S Connector, Harness Side (-)
      VPWR - Pin 1 Ground

    Is the voltage greater than 10.5 V? 

    Yes No
    GO to  DW9. REPAIR the open circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  9. DW9 CHECK THE HO2S CIRCUITS FOR AN OPEN 
    • Ignition OFF.
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) HO2S Connector, Harness Side (-) PCM Connector, Harness Side
      HO2S12 - Pin 4 HO2S12 - Pin E21
      HTR12 - Pin 2 HTR12 - Pin E35
      SIGRTN - Pin 3 SIGRTN - Pin E9

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  DW10. REPAIR the open circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  10. DW10 CHECK THE HO2S CIRCUITS FOR A SHORT 
    • Measure the resistance between:
      (+) HO2S Connector, Harness Side (-) HO2S Connector, Harness Side
      HO2S12 - Pin 4 SIGRTN - Pin 3
      HO2S12 - Pin 4 HTR12 - Pin 2
      HTR12 - Pin 2 SIGRTN - Pin 3
    • Measure the resistance between:
      (+) HO2S Connector, Harness Side (-)
      HO2S12 - Pin 4 Ground
      HTR12 - Pin 2 Ground

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to  DW11. REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  11. DW11 CHECK THE HO2S CIRCUITS FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) HO2S Connector, Harness Side (-)
      HO2S12 - Pin 4 Ground
      HTR12 - Pin 2 Ground
      SIGRTN - Pin 3 Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.    		 GO to  DW12.
  12. DW12 CHECK THE INTERNAL RESISTANCE OF THE HO2S HEATER 
    • Ignition OFF.
    • Measure the resistance between:
      (+) HO2S Connector, Component Side (-) HO2S Connector, Component Side
      HTR12 - Pin 2 VPWR - Pin 1

    Is the resistance between 3 - 30 ohms? 

    Yes No
    GO to  DW13. INSTALL a new HO2S. REFER to the Electronic Engine Controls article. RESET the keep alive memory (KAM). REFER to DIAGNOSTIC METHODS .
    REPEAT the self-test.
  13. DW13 CHECK THE HO2S SIGNAL 
    • Ignition OFF.
    • HO2S connector disconnected.
    • Ignition ON, engine running.
    • Access the PCM and monitor the O2S12 (VOLT) PID.

    Is the voltage less than 1 V? 

    Yes No
    GO to  DW14. GO to  DW15.
  14. DW14 CHECK THE HO2S CIRCUIT CONTINUITY 
    • Ignition OFF.
    • Connect a 5 amp fused jumper wire between the following:
      Point A HO2S Connector, Harness Side Point B HO2S Connector, Harness Side
      HO2S12 - Pin 4 VPWR - Pin 1
    • Ignition ON, engine running.
    • Access the PCM and monitor the O2S12 (VOLT) PID.

    Is the voltage greater than 1 V? 

    Yes No
    INSTALL a new HO2S. REFER to the Electronic Engine Controls article.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to  DW15.
  15. DW15 CHECK FOR CORRECT PCM OPERATION 
    • Ignition OFF.
    • 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 RESETTING THE KEEP ALIVE MEMORY (KAM) , 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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