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HOMESERVICE MANUALSMERCURY2010MARINER PREMIER, 2.5 7, FWDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - PINPOINT TEST DY: ENGINE OIL TEMPERATURE (EOT) SENSOR THROUGH PINPOINT TEST HE: EXHAUST GAS RECIRCULATION (EGR) SYSTEMS - (EXCEPT DIESEL & HYBRID)PINPOINT TEST HC: FUEL DELIVERY SYSTEMTEST PROCEDURE
2010 Mercury Mariner Premier, 2.5 7, FWD

Test Procedure

2010 Mercury Mariner Premier, 2.5 7, FWDSECTION Test Procedure
  1. HC1 DTC P0148 OR SYMPTOMS WITHOUT DTCS: CHECK THE SYSTEM INTEGRITY 
    • Visually inspect the complete fuel delivery system for damage and leakage.
    • Check the following:
      • fuel lines and connections
      • relays
      • fuel tank
      • fuel pump
      • fuel pressure regulator
      • fuel pulse damper
      • fuel rail at injectors
      • damaged connector pins
      • electrical connectors not fully engaged
    • Verify the vehicle has followed the maintenance schedule. A new fuel filter should have been installed within the last 48,280 km (30,000 miles) (vehicles with inline fuel filter).
    • Verify the inertia fuel shutoff (IFS) switch is set (button pushed in). Refer to the Owner's Literature, Roadside Emergencies for the location of the IFS switch (if equipped).
    • Verify the fuse integrity.
    • Verify the battery is fully charged.
    • Verify clean sufficient fuel.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    CLEAR the DTCs. REPEAT the self-test.    		 For Crown Victoria,
    Explorer,
    Explorer SportTrac,
    F-Series Super Duty,
    Grand Marquis,
    Mountaineer,
    Mustang, and
    Town Car, GO to  HC2.
    For all others, GO to  HC3.
  2. HC2 CHECK ALL SYSTEM RELATED DEVICES (SENSOR, DAMPER OR REGULATOR) FOR LEAKAGE 
    • Ignition OFF.
    • FP connector connected.
    • Remove the vacuum hose on each system device connected to the fuel rail.
    • Inspect for the presence of fuel in the vacuum line of each device connected to the fuel rail.
    • Ignition ON, engine running.
    • Check for manifold vacuum at each system related component with a vacuum line.
    • Ignition OFF.

    Are all vacuum lines for system related devices indicating no fuel present? 

    Yes No
    GO to  HC3. If the vacuum line connected to a component indicates that a fuel leak is present, INSTALL a new component.
    CLEAR the DTCs. REPEAT the self-test.
  3. HC3 CHECK THE FUEL PRESSURE 
    • Ignition OFF.
    • Relieve the fuel pressure. Refer to the appropriate Fuel System article for the Fuel System Pressure Release procedure.
    • Mechanical fuel pressure gauge connected.
    • Ignition ON, engine OFF.
    • Pressurize the fuel system. Refer to the appropriate Fuel System article for the Fuel System Pressure Release procedure to pressurize the fuel system.
    • FP connector connected.
    • Cycle the ignition several times to charge the fuel system.
    • Compare the fuel pressure reading to the Fuel System Specification Chart.

    Is the fuel pressure within range? 

    Yes No
    For DTCs P0171, P0174, P2195, or P2197, GO to  HC15.
    For all others, GO to  HC6.    		 GO to  HC4.
  4. HC4 CHECK THE FUEL PUMP GROUND CIRCUIT FOR AN OPEN CIRCUIT IN THE HARNESS 
    NOTE: Refer to the appropriate SYSTEM WIRING DIAGRAMS article for schematic and connector information.
    • FP connector disconnected.
    • Measure the voltage between:
      (+) Vehicle Battery (-) FP Connector, Harness Side
      Positive terminal FPGND

    Is the voltage greater than 10 V? 

    Yes No
    GO to  HC5. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.
  5. HC5 CHECK THE FUEL PUMP POWER CIRCUIT FOR AN OPEN IN THE HARNESS 
    NOTE: During output state control, the fuel pump stays commanded on for only about 5 seconds.
    • Verify the inertia fuel shutoff (IFS) switch is set (button pushed in). Refer to the Owner's Literature, Roadside Emergencies for the location of the IFS switch (if equipped).
    • FP connector disconnected.
    • Ignition ON, engine OFF.
    • Access the PCM and control the FP PID.
    • Be aware that output state control turns off the FP after a calibrated time. If this happens, command the outputs on again to continue testing.
    • Measure the voltage between:
      (+) FP Connector, Harness Side (-) Vehicle Battery
      FPPWR Negative terminal

    Is the voltage greater than 10 V? 

    Yes No
    GO to  HC12. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.
  6. HC6 CHECK THE SEPARATION LEVEL OF THE ETHANOL/WATER MIXTURE AND GASOLINE IN THE FUEL 
    NOTE: This step requires the use of a locally obtained 200 ml beaker and a 25 ml graduated cylinder.
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.