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HOMESERVICE MANUALSFORD2003WINDSTAR BASEREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 2539 (ENGINE CONTROLS - PINPOINT TEST A: NO START THROUGH PINPOINT TEST DJ: AIR CONDITIONER EVAPORATOR TEMPERATURE (ACET) SENSOR - CNG, FLEX-FUEL & GASOLINE)PINPOINT TEST DF: VEHICLE SPEED CIRCUIT CHECKTEST PROCEDURE
2003 Ford Windstar Base

Test Procedure

2003 Ford Windstar BaseSECTION Test Procedure
WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 2004 Mercury Sable, 2004 Mercury Mountaineer, 2004 Mercury Monterey, 2004 Mercury Marauder, and 2004 Mercury Grand Marquis. However, it is still accessible from the selected car via links, so may be relevant.
  1. DF1 DTCS P0500, P0503, P1501 AND P1502: CHECK THE VEHICLE SPEED CIRCUIT FOR INTERMITTENT CONCERNS 
    NOTE: PCM detected an error in the vehicle speed information received from the ABS control module. This test step checks for recurrence of this vehicle speed error.
    • Key ON Engine OFF.
    • Scan tool connector connected.
    • CLEAR the DTCs.
    • Take the vehicle to a suitable location and gradually increase the vehicle speed to 80 km/h (50 mph).
    • Coast down to an idle and stop the vehicle.
    • Key OFF.
    • Key ON Engine OFF.
    • CHECK Continuous Memory DTCs:

    Are DTCs P0500, P0503, P1501 or P1502 present? 

    Yes No
    KEY OFF.
    The vehicle speed input was not as expected
    GO to  DF2.    		 KEY OFF.
    The vehicle speed input was as expected. The fault that produced the original DTC may be intermittent.
    GO to  DF6.
  2. DF2 CHECK THE VSS AND VSS-GND FOR A SHORT TO POWER IN THE HARNESS 
    • PCM connector disconnected.
    • ABS Module connector disconnected.
    • Key ON Engine OFF.
    • Measure the voltage between:
    ( + )PCM Connector, Harness Side ( - )
    VSS - Pin 58 Ground
    VSS-GND - Pin 33 Ground

    Are the voltages less than 1 V? 

    Yes No
    GO to  DF3. KEY OFF.
    GO to  DF7.
  3. DF3 CHECK FOR AN OPEN VSS BETWEEN THE PCM AND ABS CONTROL MODULE 
    • Measure the resistance between:
    ( + )PCM Connector, Harness Side ( - )ABS Module Connector, Harness Side
    VSS - Pin 58 VSS - Pin 11

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  DF4. REPAIR open circuit.
    CARRY OUT the VSS Circuit Repair Verification Drive Cycle
    GO to  DF8.
  4. DF4 CHECK THE VSS-GND CIRCUIT FOR AN OPEN IN THE HARNESS 
    • Measure the resistance between:
    ( + )PCM Connector, Harness Side ( - )
    VSS-GND - Pin 33 Ground

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  DF5. REPAIR open circuit.
    CARRY OUT the VSS Circuit Repair Verification Drive Cycle
    GO to  DF8.
  5. DF5 CHECK THE VSS CIRCUIT(S) FOR A SHORT TO GROUND IN THE HARNESS 
    • Scan tool connector disconnected.
    • Measure the resistance between:
    ( + )PCM Connector, Harness Side ( - )
    VSS - Pin 58 Ground
    • Measure the resistance between:
    ( + )PCM Connector, Harness Side ( - )PCM Connector, Harness Side
    VSS - Pin 58 VSS-GND - Pin 33

    Are all the resistances greater than 10K ohms? 

    Yes No
    RESTORE vehicle.
    REFER to the appropriate ANTI-LOCK CONTROL article for further diagnosis of the ABS control module, its speed sensors and its wheel speed sensor harness circuits.
    If these components are working properly, INSTALL a new PCM.
    Refer to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .
    GO to  DF8.    		 GO to  DF7.
  6. DF6 VISUAL INSPECTION 
    • Visually inspect the VSS circuit harness and connectors at PCM, ABS and other VSS User Modules for damage, loose connections, loose grounds or incorrect routing.
    NOTE: REFER to the appropriate SYSTEM WIRING DIAGRAMS article for harness, module and connector locations.

    Did the visual inspection reveal a potential failure? 

    Yes No
    Repair the fault as necessary.
    GO to  DF8.    		 Unable to duplicate or identify the fault at this time.
    REFER to the appropriate ANTI-LOCK CONTROL article for diagnosis of intermittent control module and wheel speed sensor concerns.
  7. DF7 VERIFY IF THE VSS IS SHORTED IN HARNESS OR ANOTHER MODULE 
    • Determine which, if any, modules are connected to the VSS circuit. Refer to the appropriate SYSTEM WIRING DIAGRAMS article. If no other modules are connected to the VSS circuit, GO to the YES Action To Take.
    • One at a time, disconnect the modules associated with the VSS. After disconnecting each module, TEST again for a short circuit. Refer to test step that sent you here). Repeat until each associated module is disconnected or the short circuit is eliminated.

    Did the short circuit remain after all associated modules were disconnected? 

    Yes No
    REPAIR short circuit.
    GO to  DF8.    		 REFER to the appropriate article for further diagnosis of the appropriate module.
    After the repair, RESTORE the vehicle.
    GO to  DF8.
  8. DF8 VSS CIRCUIT REPAIR VERIFICATION DRIVE CYCLE 
    NOTE: Warm the engine to normal operating temperature before continuing.
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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.