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Home >> Ford >> 2008 >> Expedition EL RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (Four Wheel Drive (4WD) Systems) >> Diagnostic Tests >> Four Wheel Drive (4WD) Systems - 2-Speed Torque-On-Demand >> Pinpoint Tests >> Pinpoint Test R: The Four Wheel Drive (4WD) System Jumps Out of Gear >> Pinpoint Test R: The Four Wheel Drive (4WD) System Jumps Out Of Gear

Pinpoint Test R: The Four Wheel Drive (4WD) System Jumps Out Of Gear

WARNING: This page is about a different variant/trim than selected.
  1. R1 CHECK FOR OBSTRUCTED IWE VENT LINES 
    • With the vehicle in NEUTRAL, position it on a hoist. Refer to JACKING AND LIFTING article.
      • NOTE: The IWE vent port is the smaller of the 2 vacuum ports.
    • Disconnect the LH IWE line from the vent port.
    • Attach a hand vacuum pump to the IWE vent line.
    • Attempt to draw and hold a vacuum.
    • Connect the LH IWE line.
    • Disconnect the RH IWE line from the vent port.
    • Attempt to draw and hold a vacuum.
    • Can a vacuum be held on either IWE vent line? 
    1. YES  : INSTALL new IWE vent lines as necessary. TEST the system for normal operation.
    2. NO  : Go to  R2.
  2. R2 VERIFY THE CONCERN 
    • Drive the vehicle and attempt to duplicate the concern.
    • Is the concern an uncommanded range shift (in or out of 4L mode)? 
    1. YES  : Go to  R5.
    2. NO  : Go to  R3.
  3. R3 CHECK THE 4WD SWITCH STATUS (4WDINP_SW) PID 
    • Key in OFF position.
    • Connect the diagnostic tool.
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger - 4X4 Control Module
    • Drive the vehicle.
    • Dynamically monitor the 4WDINP_SW PID while driving the vehicle in each MSS position.
      MSS Position PID Status
      2H 2-W Drive
      4A A4WD
      4H 4W Auto/Hi
      4L 4W Low
    • Does the 4WDINP_SW PID always agree with the MSS position? 
    1. YES  : Go to  R4.
    2. NO  : Go to Pinpoint Test N .
  4. R4 CHECK FOR DTCs 
    • Carry out the 4X4 control module on-demand self test.
    • Are DTCs present? 
    1. YES  : REFER to the 4X4 Control Module DTC Chart.
    2. NO  : Go to Pinpoint Test U .
  5. R5 CHECK THE 4WD INDICATORS 
    • Stop the vehicle.
    • Shift the transmission into the NEUTRAL position.
      • NOTE: 2H is indicated by the absence of 4X4 AUTO, 4H or 4L mode indicators in the Instrument Cluster (IC) message center.
    • Observe the 4WD indicators in the IC while cycling through each MSS position.
      MSS Switch Position 4WD Indicator
      2H -
      4A 4X4 AUTO
      4H 4X4
      4L 4X4 LOW
    • Do the 4WD indicators match MSS switch positions? 
    1. YES  : Go to  R3.
    2. NO  : Go to  R6.
  6. R6 CHECK FOR DTCs 
    • Shift the transmission into the PARK position.
    • Carry out the on-demand self test.
    • Are DTCs present? 
    1. YES  : REFER to the 4X4 Control Module DTC Chart.
    2. NO  : CHECK the transfer case fluid level. REFER to TRANSFER CASE article. If the fluid level is OK, CHECK for internal transfer case faults. REFER to TRANSFER CASE article. TEST the system for normal operation.
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