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Home >> Ford >> 2004 >> Freestar Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Pinpoint Test DX: Engine Coolant Temperature (ECT) Sensor Through Pinpoint Test HC: Fuel Delivery System - CNG, Flex-Fuel & Gasoline >> Pinpoint Test HC: Fuel Delivery System >> Test Procedure

Test Procedure

NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION  table of fault code setting condition.
FAULT CODE SETTING CONDITION

Fault Code KOEO KOER Continuous Memory
P0148      HC1
  1. HC1 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. (Fuel filter should have been replaced within the last 48,280 km (30,000 miles)).
    • VERIFY the Inertia Fuel Shutoff (IFS) switch is set (button pushed in). REFER to the Owner Guide for location.
    • Verify the fuse integrity.
    • Verify the battery is fully charged.
    • Verify clean sufficient fuel.

    Are any of the above concerns present? 

    Yes No
    REPAIR as necessary. GO to  HC2.
  2. HC2 CHECK ALL SYSTEM RELATED DEVICES (SENSOR, DAMPER OR REGULATOR) FOR LEAKAGE 
    • Key in OFF position.
    • FP connector connected.
    • Key ON, engine running.
    • Check for manifold vacuum at each system related component with a vacuum line.
    • Key in OFF position.
    • Wait 10 seconds.
    • Key ON, engine running.
    • Run the engine for approximately 10 seconds.
    • Key in OFF position.
    • 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.

    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.
  3. HC3 CHECK THE FUEL PRESSURE 
    WARNING: BEFORE SERVICING OR REPLACING ANY COMPONENTS IN THE FUEL SYSTEM, REDUCE THE POSSIBILITY OF INJURY OR FIRE BY FOLLOWING THE WARNING, CAUTION, AND HANDLING DIRECTIONS IN SAFE FUEL HANDLING PRACTICES: GASOLINE, METHANOL, AND METHANOL BLENDS  AT BEGINNING OF THIS PINPOINT TEST.
    • Key in OFF position.
    • Relieve the fuel pressure. Refer to the appropriate FUEL SYSTEM article for the Fuel System Pressure Release procedure.
    • Mechanical fuel pressure gauge connected.
    • Key ON, engine OFF.
    • Pressurize the fuel system. Refer to the appropriate FUEL SYSTEM article for Fuel System for the Fuel System Pressure Release procedure.
    • Compare the fuel pressure reading to the Fuel System Specification Chart.

    Is the fuel pressure within range? 

    Yes No
    GO to  HC6. GO to  HC4.
  4. HC4 CHECK THE VOLTAGE AT THE FUEL PUMP HARNESS CONNECTOR 
    • FP connector disconnected.
      NOTE: REFER to the appropriate SYSTEM WIRING DIAGRAMS article for correct pin location.
    • 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. Key in OFF position. REPAIR the open circuit.
  5. HC5 CHECK THE VOLTAGE AT THE FUEL PUMP HARNESS CONNECTOR 
    • VERIFY the Inertia Fuel Shutoff (IFS) switch is set (button pushed in). REFER to the Owner Guide for location.
    • FP connector disconnected.
    • Key ON, engine OFF.
    • Access the PCM and control the FP PID.
    • Be aware that Output Test Mode 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
    Key in OFF position.
    EXIT the Output State Control.
    GO to  HC6.    		 Key in OFF position. REPAIR the open circuit.
  6. HC6 CHECK THE FUEL PRESSURE LEAKDOWN 
    NOTE: When the fuel pump is commanded off, the fuel pressure may substantially decrease and then stabilize.
    NOTE: During Output State Control, the fuel pump stays commanded on for only about 5 seconds.
    • Mechanical fuel pressure gauge connected.
    • Key ON, engine OFF.
    • Access the PCM and control the FP PID.
    • Run the fuel pump to obtain maximum fuel pressure.
    • Command the fuel pump off.
    • Allow the fuel pressure to stabilize.
    • Record the stabilized reading.
    • Monitor the fuel pressure for 1 minute.

    Does the fuel pressure remain within 34 kPa (5 psi) of the recorded reading (RFS, MRFS) or greater than 275 kPa (40 psi) (ERFS) after 1 minute? 

    Yes No
    For ERFS, GO to  HC13.
    For MRFS, GO to  HC14.
    For RFS, GO to  HC7.    		 Fuel rail pressure leakdown
    GO to  HC12.
  7. HC7 CHECK FOR A VACUUM SOURCE 
    • Key ON, engine running.

    Is the vacuum level at the Fuel Pressure Regulator equal to manifold vacuum? 

    Yes No
    GO to  HC8. Repair as required.
  8. HC8 CHECK THE FUEL PRESSURE REGULATOR RESPONSE 
    • Install the fuel pressure tester.
    • Disconnect the vacuum hose at the pressure regulator.
    • Plug the hose.
    • Drive the vehicle with heavy accelerations while observing the fuel pressure gauge reading.

    Does the fuel pressure reading hold steady within 21 kPa (3 psi) during the test? 

    Yes No
    GO to  HC9. GO to  HC14.
  9. HC9 CHECK THE FUEL PRESSURE REGULATOR RESPONSE TO THE DECREASE IN MANIFOLD VACUUM 
    • Install the fuel pressure tester.
    • Key ON, engine running.
    • Rapidly accelerate the engine speed to 2,500 RPM, then return to idle.

    Does the fuel pressure increase during rapid acceleration? 

    Yes No
    GO to  HC10. INSTALL a new fuel pressure regulator assembly.
  10. HC10 CHECK FOR A RESTRICTED FUEL RETURN LINE 
    • Install the fuel pressure tester.
    • REMOVE the fuel return line at the fuel rail.
    • Connect the short hose from the fuel rail to a clean container of at least 1.1 liter (1.0 quart) capacity.
    • Key ON, engine OFF.
    • Access the PCM and control the FP PID.
    • Run the fuel pump to obtain maximum fuel flow.
    • Record the fuel pressure.
    • Observe if fuel is being returned to the container.

    Is the fuel pressure within range? 

    Yes No
    GO to  HC11. INSTALL a new fuel pressure regulator assembly.
  11. HC11 CHECK THE FUEL RETURN SYSTEM 
    NOTE: Observe the Warnings, Cautions, and Notes.
    • Key in OFF position.
    • Disconnect the fuel return line at the fuel rail.
    • Disconnect the fuel return line at the fuel pump.
    • CHECK for a restricted fuel return line.
    • Apply 21 to 34 kPa (3 to 5 psi) regulated shop air to the return line pressure.

    Does air flow freely through the line? 

    Yes No
    GO to  HC12. REPAIR the fuel return line
  12. HC12 CHECK FUEL INJECTOR FLOW AND LEAKAGE 
    NOTE: Observe the Warnings, Cautions, and Notes.
    • Check the fuel injectors for leakage and flow rate using the injector flow tester.

    Are test results satisfactory? 

    Yes No
    For ERFS, GO to  HC13.
    For all others, GO to  HC14    		 INSTALL a new fuel injector as necessary.
  13. HC13 COMPARE THE FRP PID TO THE MECHANICAL GAUGE 
    NOTE: Most mechanical gauges are referenced to atmospheric pressure. The FRP sensor is referenced to manifold pressure. In order to make a valid comparison, the engine must be off.
    NOTE: The vehicle may exhibit a long crank until the fuel system is pressurized.
    • Key in OFF position.
    • Relieve the fuel pressure. Refer to the for the appropriate FUEL SYSTEM article for Fuel System Pressure Release procedure.
    • Disable the fuel pump.
    • Key ON, engine OFF.
    • Monitor the mechanical gauge.
    • Access the PCM and monitor the FRP PID.
    • Compare the FRP PID value to the mechanical gauge.
    • Key in OFF position.
    • Pressurize the fuel system. Refer to the appropriate FUEL SYSTEM article for Fuel System for the Fuel System Pressure Release procedure.
    • Key ON, engine running.
    • Allow the fuel pressure to stabilize.
    • Key in OFF position.
    • Key ON, engine OFF.
    • Compare the FRP PID value to the mechanical gauge.

    Are the FRP PID values within 34 kPa (5 psi) of the mechanical gauge readings? 

    Yes No
    GO to  HC14. INSTALL a new FRP sensor.
    REFER to the fuel system WARNING information in SAFE FUEL HANDLING PRACTICES: GASOLINE, METHANOL, AND METHANOL BLENDS  at the beginning of this pinpoint test.
  14. HC14 CHECK THE FUEL SUPPLY LINE FOR RESTRICTION 
    NOTE: Observe the Warnings, Cautions, and Notes.
    • Disconnect the fuel supply line at the fuel rail.
    • Disconnect the fuel supply line at the fuel pump.
    • Check the fuel supply line for restriction.
    • Apply 21 to 34 kPa (3 to 5 psi) air pressure to the fuel supply line.

    Does air flow freely through the line? 

    Yes No
    INSTALL a new FP module. REPAIR the cause of the restriction
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