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Home >> Ford >> 2022 >> Expedition SSV, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Four-Wheel Drive Systems) >> Diagnosis And Testing >> DTC Chart and Pinpoint Tests - Vehicles With: 2-Speed Torque On Demand Transfer Case >> Pinpoint Tests >> Pinpoint Test B: 4WD (Four-Wheel Drive) Clutch Field Coil - Electrical

Pinpoint Test B: 4WD (Four-Wheel Drive) Clutch Field Coil - Electrical

WARNING: This page is about a different variant/trim than selected.
  1. Refer to FOUR WHEEL DRIVE SYSTEMS for schematic and connector information.

    Normal Operation and Fault Conditions 

    When the transfer case is in 4A and 4H modes, the TCCM provides a PWM voltage to the transfer case clutch field coil. The energized field coil moves a ball and ramp cam to engage a clutch as necessary to provide torque to the front axle.

    The TCCM4WD clutch field coil driver monitors the circuit for open circuit, short to power, and short to ground. If an electrical fault is detected, the TCCM will store a DTC.

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    TCCM P1825:00 4-Wheel Drive Clutch Relay Open Circuit: No Sub Type Information This DTC sets when TCCM detects an open circuit. The TCCM disables transfer case clutch operation.
    TCCM P1826:00 4-Wheel Drive Low Clutch Relay Circuit To Battery: No Sub Type Information This DTC sets when TCCM detects a short to voltage. Transfer case clutch operation, though disabled by the TCCM, is fully engaged when this DTC is present.
    TCCM P1827:00 4-Wheel Drive Low Clutch Relay Circuit To Ground: No Sub Type Information This DTC sets when TCCM detects a short to ground. The TCCM disables transfer case clutch operation.

    Possible Sources 

    • Clutch control circuit short to ground
    • Clutch control open circuit
    • Clutch control circuit short to voltage
    • Clutch control ground open circuit
    • Clutch field coil

  2. B1 CHECK FOR TCCM (TRANSFER CASE CONTROL MODULE) DTC (DIAGNOSTIC TROUBLE CODE)

    • Ignition ON.

    • Enter the following diagnostic mode on the scan tool: TCCM On Demand Self-Test.

    Are any DTC present? 

    Yes  For DTC P1825:00, GO to  B3. For DTC P1826:00, GO to  B4. For DTC P1827:00, GO to  B2
    For all other DTC's, the DTC chart: TCCM.
    No  The 4WD clutch field coil is electrically sound at this time.

  3. B2 CHECK CLUTCH CONTROL CIRCUIT FOR A SHORT TO GROUND

    • Ignition OFF.

    • Disconnect Transfer Case C350 .

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C350-2
      GFD699631Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the resistance greater than 10, 000 ohms? 

    Yes  GO to  B3
    No  REPAIR the short to GND.

  4. B3 CHECK CLUTCH CONTROL CIRCUIT FOR AN OPEN

    • Ignition OFF.

    • Disconnect Transfer Case C350 .

    • Disconnect TCCM C2371B .
      Positive Lead Measurement / Action Negative Lead
      C350-2
      GFD699631Courtesy of FORD MOTOR COMPANY
      		 C2371B-10

    Is the resistance less than 3 ohms? 

    Yes  GO to  B4
    No  REPAIR the open circuit.

  5. B4 CHECK CLUTCH CONTROL CIRCUIT FOR A SHORT TO VOLTAGE

    • Ignition OFF.

    • Disconnect Transfer Case C350 .

    • Ignition ON.

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C350-2
      GFD699632Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is any voltage present? 

    Yes  REPAIR the short to voltage.
    No  CHECK OASIS for any applicable service articles: TSB, GSB, SSM, or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, Replace field coil.
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