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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 W: Vehicle Binds in a Turn/Resists Turning/Pulsates in a Straight-line in 4WD Mode >> Pinpoint Test W: Vehicle Binds In A Turn/Resists Turning/Pulsates In A Straight-Line In 4WD Mode

Pinpoint Test W: Vehicle Binds In A Turn/Resists Turning/Pulsates In A Straight-Line In 4WD Mode

WARNING: This page is about a different variant/trim than selected.
NOTE: 4X4 is not intended for driving on hard/dry surfaces; using 4X4 mode while driving on these surfaces may produce noises like intermittent clunking, but will not damage driveline components.
  1. W1 VERIFY THE CONCERN 
    • Test drive the vehicle on a straight stretch of road in 4A mode.
    • Drive the vehicle through turns and parking lot maneuvers.
    • Does the vehicle bind, pulsate or shudder? 
    1. YES  : If the problem occurs in 4A mode, go to  W2; If 4H mode or 4L mode, binding is a normal condition.
    2. NO  : Go to Pinpoint Test S .
  2. W2 CHECK THE 4H AND 4L INDICATORS 
    • Review the test drive notes.
    • Did the 4X4 (4H) or 4X4 LOW (4L) or powertrain malfunction indicator (wrench light) illuminate in the Instrument Cluster (IC) message center? 
    1. YES  : If the powertrain malfunction indicator (wrench light) illuminated, go to  W4.

      If the 4H mode or 4L mode indicators illuminated, go to  W3.

    2. NO  : Go to  W5.
  3. W3 VERIFY THE FAULT 
    • Review the test drive notes.
    • Was 4H mode or 4L mode selected when the 4X4 (4H) or 4X4 LOW (4L) indicators were illuminated in the IC message center? 
    1. YES  : The system is functioning correctly.
    2. NO  : The fault may have been caused by an intermittent, uncommanded or auto lock shift. TEST the system for normal operation. Go to Pinpoint Test S .
  4. W4 CHECK FOR DTCs 
    • Connect the diagnostic tool.
    • Carry out the 4X4 control module on-demand self test.
    • Are DTCs retrieved? 
    1. YES  : REFER to the 4X4 Control Module DTC Chart for diagnosis.
    2. NO  : Go to  W5.
  5. W5 VERIFY THE CONCERN 
    • Disconnect: Transfer Case C350
    • Test drive the vehicle on a straight stretch of road and in turns, and shift the transfer case through each mode. Record any fault conditions.
    • Is the concern present? 
    1. YES  : INSPECT the driveline components for damage or wear. REFER to Inspection and Verification . TEST the system for normal operation.
    2. NO  : Go to  W6.
  6. W6 CHECK THE 4WD CLUTCH PWM STATUS (4WDCPWMST) PID 
    • Connect: Transfer Case C350
    • CLEAR the DTCs.
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger - 4X4 Control Module
    • Monitor the 4WDCPWMST PID at closed throttle, Key ON Engine OFF (KOEO).
    • Select 4H mode.
    • Is the 4WDCPWMST PID at least 12%? 
    1. YES  : Go to  W7.
    2. NO  : CHECK the transfer case. REFER to TRANSFER CASE article. TEST the system for normal operation.
  7. W7 CHECK THE ABS MODULE WHEEL SPEED SENSOR PIDs 
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger - ABS Module
    • While driving the vehicle at 30 km/h (18 mph), monitor the following wheel speed sensor PIDs:
      • Left Front Wheel Speed Sensor (LF_WSPD)
      • Left Rear Wheel Speed Sensor (LR_WSPD)
      • Right Front Wheel Speed Sensor (RF_WSPD)
      • Right Rear Wheel Speed Sensor (RR_WSPD)
    • Compare the speedometer reading to the wheel speed sensor PIDs.
    • Do the wheel speed sensor PIDs and speedometer speeds match within 1.5 km/h (1 mph)? 
    1. YES  : Go to  W8.
    2. NO  : VERIFY that the 4 road wheels are the same size and have similar tread depth. CHECK the ABS for faults. REFER to VEHICLE DYNAMIC SYSTEMS article. TEST the system for normal operation.
  8. W8 CHECK THE THROTTLE POSITION STATUS (TPI) PID 
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger - 4X4 Control Module
      • NOTE: The TPI PID is Accelerator Pedal Position (APP) as communicated by the PCM via High Speed Controller Area Network (HS-CAN).
    • Slowly move accelerator pedal from closed throttle to Wide Open Throttle (WOT) and observe the TPI PID.
    • Does the TPI PID value vary between 0 at closed throttle and 255 at WOT? 
    1. YES  : Go to  W9.
    2. NO  : Diagnose the PCM. REFER to the Introduction - Gasoline Engines article. TEST the system for normal operation.
  9. W9 CHECK THE TRANSFER CASE FRONT DRIVESHAFT OUTPUT 
    • With the vehicle in NEUTRAL, position it on a hoist. Refer to JACKING AND LIFTING article.
    • Rotate the front driveshaft by hand.
    • Does the front driveshaft rotate freely (does it require less than 45 Nm [33 lb-ft] to rotate)? 
    1. YES  : INSTALL a new 4X4 control module. REFER to 4X4 Control Module . TEST the system for normal operation.
    2. NO  : CHECK the transfer case. REFER to TRANSFER CASE article. TEST the system for normal operation.
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