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HOMESERVICE MANUALSFORD2004MUSTANG BASE, 2D COUPE, 3.9 6, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 2542 (ENGINE CONTROLS - PINPOINT TEST A: NO START THROUGH PINPOINT TEST DK: ACCELERATOR PEDAL POSITION (APP) SENSOR - (EXCEPT DIESEL & HYBRID))PINPOINT TEST DI: DIRECT FUEL INJECTION FUEL INJECTORTEST PROCEDURE
2004 Ford Mustang Base, 2D Coupe, 3.9 6, Automatic

Test Procedure

2004 Ford Mustang Base, 2D Coupe, 3.9 6, AutomaticSECTION Test Procedure
WARNING: This page does not describe the selected car, but rather 22 other vehicles, including the 2011 Mercury Milan, 2011 Mercury Mariner, 2011 Mercury Grand Marquis, 2011 Lincoln Town Car, and 2011 Lincoln Navigator L. However, it is still accessible from the selected car via links, so may be relevant.
  1. DI1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) 

    Are DTCs P0201, P0202, P0203, P0204, P0205, or P0206 present? 

    Yes No
    GO to  DI2. For runs rough at idle or misses, GO to  DI2.
    For all others, GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .
  2. DI2 CHECK THE FUEL INJECTOR PID 
    • Access the PCM and monitor the INJ_F (MODE) PID.

    Does the INJ_F PID indicate a concern? 

    Yes No
    GO to  DI4. GO to  DI3.
  3. DI3 CARRY OUT THE RELATIVE INJECTOR FLOW TEST 
    • Verify the low pressure fuel system is operating correctly. GO to PINPOINT TEST HC and follow the pinpoint test direction.
    • Carry out the Relative Injector Flow Test. Refer to the instruction manual provided by the scan tool manufacturer.

    Are the results satisfactory? 

    Yes No
    The system is operating correctly at this time.
    RETURN to SYMPTOM CHARTS for further direction.    		 GO to  DI4.
  4. DI4 CHECK THE INJ AND INJRTN CIRCUITS FOR AN OPEN IN THE HARNESS 
    • Ignition OFF.
    • INJ connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) PCM Connector, Harness Side (-) INJ Connector, Harness Side
      Suspect INJ INJ
      Suspect INJRTN INJRTN

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  DI5. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  5. DI5 CHECK THE INJ AND INJRTN CIRCUITS FOR A SHORT TO GROUND 
    • Ignition OFF.
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) INJ Connector, Harness Side (-)
      INJ Ground
      INJRTN Ground

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to  DI6. REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.
  6. DI6 CHECK THE INJ AND INJRTN CIRCUITS FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      VOLTAGE REFERENCE CHART

      (+) INJ Connector, Harness Side (-)
      INJ Ground
      INJRTN Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to  DI7.
  7. DI7 CHECK FOR A SHORT BETWEEN THE INJ AND INJRTN CIRCUITS 
    • Ignition OFF.
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) INJ Connector, Harness Side (-) INJ Connector, Harness Side
      INJ INJRTN

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  DI8. REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.
  8. DI8 CHECK THE RESISTANCE OF THE FUEL INJECTOR 
    • Measure the resistance between:
      RESISTANCE REFERENCE CHART

      (+) INJ Connector, Component Side (-) INJ Connector, Component Side
      INJ INJRTN

    Is the resistance between 1 - 2 ohms? 

    Yes No
    GO to  DI9. INSTALL a new Fuel Injector. REFER to the appropriate Fuel Charging and Controls article . RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.
  9. DI9 CARRY OUT A THOROUGH WIGGLE TEST ON THE FUEL INJECTOR HARNESS 
    • Ignition OFF.
    • INJ connector connected.
    • PCM connector connected.
    • Ignition ON, engine running.
    • Engine at normal operating temperature.
    • Access the PCM and monitor the INJ_F (MODE) PID.
    • Wiggle, shake, and bend small sections of the wiring harness while working from the suspected fuel injector to the PCM.

    Does the INJ_F PID indicate a concern? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For Relative Fuel Injector Test results indicating a fuel injector concern, INSTALL a new fuel injector as necessary. REFER to the appropriate Fuel Charging and Controls . RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) . REPEAT the self-test.
    For all others, GO to  DI10.
  10. DI10 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.
    GO to PINPOINT TEST Z .
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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.