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HOMESERVICE MANUALSMERCURY2011MARINER PREMIER, 2.5 7, AWDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - PINPOINT TEST DL: CYLINDER HEAD TEMPERATURE (CHT) SENSOR THROUGH PINPOINT TEST DX: ENGINE COOLANT TEMPERATURE (ECT) SENSOR - (EXCEPT DIESEL & HYBRID)PINPOINT TEST DW: HEATED OXYGEN SENSOR (HO2S)TEST PROCEDURE
2011 Mercury Mariner Premier, 2.5 7, AWD

Test Procedure

2011 Mercury Mariner Premier, 2.5 7, AWDSECTION Test Procedure
  1. DW1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) 

    Are DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0040, P0041, P0053, P0054, P0059, P0060, P0130, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0139, P013A, P013B, P013C, P013E, P0140, P0141, P014A, P0152, P0153, P0155, P0157, P0158, P0159, P0161, P016A, P1127, P2297, P2A01, or P2A04 present? 

    Yes No
    For DTCs P0040 or P0041, GO to  DW2.
    For DTCs P0133, P0134, P013B, P0140, P0153 or P2297, GO to  DW3.
    For DTC P1127, GO to  DW18.
    For all others, GO to  DW5.    		 For all others, GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .
  2. DW2 CROSSED SENSOR WIRES 
    • Ignition OFF.
    • Check the vehicle repair history.
    • Verify the HO2S 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 .
  3. DW3 CARRY OUT THE KOER SELF-TEST 
    • Engine at normal operating temperature.
    • Carry out the PCM self-test.

    Are DTCs P0040, P0041 or P1127 present? 

    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  DW4.
  4. DW4 CHECK THE HO2S RESPONSE TEST RESULTS 

    Is the indicated value greater than the minimum threshold? 

    Yes No
    Clear the PCM DTCs.
    GO to  DW3.    		 GO to  DW5.
  5. DW5 VISUALLY INSPECT THE HO2S HARNESS 
    • Ignition OFF.
    • Visually inspect for:
      • pinched, shorted, and corroded wiring and pins
      • oil or water contamination
      • crossed sensor wires
      • damaged HO2S sensor

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0053, P0054, P0059, P0060, P0135, P0141, P0155 or P0161, GO to  DW13.
    For DTCs P0132, P0138, P0152 or P0158, GO to  DW19.
    For DTCs P0130, P0131, P0136, P0137, P0157 or P016A, GO to  DW9.
    For DTCs P013A, P013C, P013E or P014A, GO to  DW23.
    For all others, GO to  DW6.
  6. DW6 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 air flow (MAF) sensor assembly
      • hoses connecting to the throttle body
      • intake manifold gasket leaks
      • 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) .
    REPEAT the self-test.    		 GO to  DW7.
  7. DW7 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
      • 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  DW8.
  8. DW8 CHECK FOR EXHAUST SYSTEM AND FUEL SELECTION CONCERNS 
    • Inspect the exhaust system for the following:
      • exhaust leaks at flanges and gaskets
      • exhaust leaks at the HO2S
      • aftermarket accessories and performance modifications
    • Verify with the customer that flex fuel is not being used on a non-flex fuel vehicle.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to  DW9.
  9. DW9 CHECK THE HO2S CIRCUIT(S) FOR AN OPEN IN THE HARNESS 
    NOTE: Diagnose the suspect sensor indicated by the DTC.
RENDER: 1.0x

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When to See a Mechanic

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.