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Home >> Ford >> 2002 >> Excursion 7.3 F, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1058 (Four-Wheel Drive Systems) >> Diagnosis And Testing >> Four-Wheel Drive Systems - 2-Speed Torque-On-Demand >> Pinpoint Tests >> Possible Causes >> Pinpoint Test L: 4WD System Functional Test
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Pinpoint Test L: 4WD System Functional Test

WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: 4H and 4L modes are not intended for driving on hard/dry surfaces.
  1. L1 CHECK 4WD INDICATOR PROVE-OUT 
    • Key in ON position.
    • Do the 4WD indicators illuminate at prove out? 
  2. L2 CHECK 4WD AUTO OPERATION 
    • If in 4L, switch the MSS to 4WD AUTO.
    • Are the 4WD indicators off? 
    • Yes  : GO to  L5.
    • No  : GO to L3.
  3. L3 CHECK FOR DTCs 
    • Connect the diagnostic tool.
    • Carry out the on-demand self test.
    • Are DTCS present? 
  4. L4 CHECK FOR WIND-UP IN 4WD AUTO 
    • Drive the vehicle on a dry, hard surface in turns.
    • Is wind-up present in turns? 
  5. L5 CHECK THE TRANSFER CASE CLUTCH DUTY CYCLE PID 
    • Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
    • Monitor the transfer case clutch duty cycle (pulse width modulated-[PWM]) PID.
    • Does the PID indicate 2 to 4% clutch application at closed throttle? 
    • Yes  : GO to  L7.
    • No  : GO to L6.
  6. L6 CHECK THE CONTACT PLATE ENCODER PIDs 
    • Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
    • Monitor the contact plate position PIDs. Refer to the following CHART :
      CONTACT PLATE POSITION PID SPECIFICATION

      Contact Plate Position PID MSS PID 4WD AUTO/4H MSS PID 4L
      PLATE___A CLOSED OPEN
      PLATE___B OPEN CLOSED
      PLATE___C CLOSED OPEN
      PLATE___D CLOSED CLOSED
    • Does the contact plate position PID indicate that the shift motor is in 4WD Auto? 
  7. L7 CHECK SHAFT SPEED PIDs 
    • Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
    • Monitor the transfer case front and rear shaft speeds.
    • Drive the vehicle 30 km/h (18 mph).
    • Record and compare the front wheel speed and the rear wheel speed.
    • Do the front shaft speed and rear shaft speed values match within 1.5 km/h (1 mph)? 
    • Yes  : GO to L8.
    • No  : CHECK the ABS system. REFER to ANTI-LOCK CONTROL and VERIFY that the four road tire sizes match.
  8. L8 CHECK THE THROTTLE POSITION PID 
    • Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
    • Monitor the throttle position PID from the 4x4 module.
    • Key ON, engine OFF.
    • Slowly move throttle from closed throttle to WOT and observe the 4WD module throttle sensor PID.
    • Does the PID value vary between 0% at closed throttle and 100% at WOT? 
  9. L9 CHECK FOR WIND-UP IN TURNS ON THROTTLE 
    • Drive the vehicle on a dry, hard surface, executing turns while applying the throttle.
    • Is wind-up present? 
  10. L10 CHECK 4H OPERATION 
    • Select 4H.
    • Does the 4H indicator illuminate correctly? 
    • Yes  : GO to L11.
    • No  : GO to  L12.
  11. L11 CHECK FOR 4H WIND-UP 
    • Drive the vehicle on a dry, hard surface in turns.
    • Is wind-up present in turns? 
  12. L12 CHECK FOR DTCs 
    • Connect the diagnostic tool.
    • Carry out the on-demand self test.
    • Are DTCS present? 
  13. L13 CHECK FOR WIND-UP IN 4H ON THROTTLE 
    • Drive the vehicle on a dry, hard surface in turns while applying the throttle.
    • Is wind-up present in turns? 
  14. L14 CHECK 4L OPERATION 
    • Select 4L:
      • Vehicle stationary.
      • Press the brake.
      • Shift the transmission to N (NEUTRAL).
      • Select 4L.
      • Wait for the 4WD LOW indicator to illuminate in the instrument cluster indicating that the shift is complete.
    • Does the 4L indicator illuminate? 
    • Yes  : GO to L15.
    • No  : GO to  L16.
  15. L15 CHECK FOR WIND-UP IN 4L MODE 
    • Drive the vehicle on a dry, hard surface in turns while applying the throttle.
    • Is wind-up present in turns? 
    • Yes  : GO to  L19.
    • No  : GO to  L17.
  16. L16 CHECK FOR DTCs 
    • Connect the diagnostic tool.
    • Carry out the on-demand self test.
    • Are DTCS present? 
  17. L17 CHECK FOR DTCs 
    • Connect the diagnostic tool.
    • Carry out the on-demand self test.
    • Are DTCs present? 
  18. L18 CHECK FOR WIND-UP IN 4L MODE 
    • Drive the vehicle on a dry, hard surface in turns while applying the throttle.
    • Is wind-up present in turns? 
  19. L19 CHECK 4WD AUTO OPERATION 
    • Switch the MSS to 4WD AUTO.
    • Do the 4WD indicators turn off? 
    • Yes  : The 4WD system is operating correctly.
    • No  : GO to L20.
  20. L20 CHECK FOR DTCs 
    • Carry out the on-demand self test.
    • Are DTCs retrieved? 
    • Yes  : REFER the 4WD Control Module (PCM) DTC Index.
    • No  : GO to L21.
  21. L21 CHECK FOR WIND-UP IN 4WD AUTO 
    • Drive the vehicle on a dry, hard surface in turns.
    • Is wind-up present in turns? 
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