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Pinpoint Test K: DTC U0102

  1. Refer to Module Communications Network for schematic and connector information.

    Normal Operation and Fault Conditions 

    The GSM uses information contained in messages from the TCCM sent on the HS-CAN.

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    GSM U0102:00 Lost Communication with Transfer Case Control Module: No Sub Type Information This DTC sets if the GSM does not receive some or all of an expected message from the TCCM.

    Possible Sources 

    • Communication concern
    • ABS
    • GSM

  2. K1 VERIFY THE SCAN TOOL COMMUNICATES WITH THE TCCM (TRANSFER CASE CONTROL MODULE)

    • Ignition ON.

    • Using the diagnostic scan tool, perform the TCCM self-test.

    Did the TCCM complete the network test? 

    Yes  GO to  K2
    No  To diagnose the module does not respond to the scan tool, REFER to: Communications Network .

  3. K2 RETRIEVE THE RECORDED DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE TCCM (TRANSFER CASE CONTROL MODULE) SELF-TEST

    • Check for DTCs from the self-test.

    Are any non-network diagnostic trouble codes (DTCs) present? 

    Yes  Diagnose those diagnostic trouble codes (DTCs) first. REFER to: Four-Wheel Drive Systems - Vehicles With: 1-Speed Torque On Demand Transfer Case . REFER to: Four-Wheel Drive Systems - Vehicles With: 2-Speed Torque On Demand Transfer Case .
    No  GO to  K3

  4. K3 CHECK THE GSM (GEAR SHIFT MODULE) FOR DIAGNOSTIC TROUBLE CODES (DTCS)

    NOTE: If a GSM self-test is carried out, the driver door must be fully closed and locked. A false P166B DTC may set if the driver door is not fully closed and locked.

    • Using the diagnostic scan tool, carry out the GSM self-test.

    Are any non-network diagnostic trouble codes (DTCs) present? 

    Yes  RESOLVE those diagnostic trouble codes (DTCs) first. REFER to the Diagnostic Trouble Code (DTC) Chart 
    No  GO to  K4

  5. K4 CHECK THE GWM (GATEWAY MODULE A) FOR DIAGNOSTIC TROUBLE CODES (DTCS)

    • Using a diagnostic scan tool, carry out the GWM self-test.

    Are any diagnostic trouble codes (DTCs) present? 

    Yes  REFER to: Communications Network .
    No  GO to  K5

  6. K5 RECHECK THE GSM (GEAR SHIFT MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

    NOTE: If a GSM self-test is carried out, the driver door must be fully closed and locked. A false P166B DTC may set if the driver door is not fully closed and locked.

    • Using a diagnostic scan tool, clear the GSMDTCs.

    • Road test the vehicle.

    • Using a diagnostic scan tool, carry out the GSM self-test.

    Is DTC U0102 still present? 

    Yes  GO to  K6
    No  The system is operating correctly at this time. The DTC may have set due to high network traffic or an intermittent fault condition.

  7. K6 CHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0102 SET IN OTHER MODULES

    • Using the diagnostic scan tool, perform the self-test for all modules.

    • Retrieve the diagnostic trouble codes (DTCs) from all modules.

    Is DTC U0102 present in other modules? 

    Yes  GO to  K7
    No  GO to  K8

  8. K7 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION

    • Ignition OFF.

    • Disconnect and inspect the TCCM and related in-line connectors.

    • Repair:

      • corrosion (install new connector or terminals - clean module pins)
      • damaged or bent pins - install new terminals/pins
      • pushed-out pins - install new pins as necessary

    • Reconnect the TCCM and all related in-line connectors. Make sure they seat and latch correctly.

    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes  CHECK OASIS for any applicable service articles: TSB, GSB (general service bulletin), SSM (special service message) or FSA (Field Service Action). If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new TCCM. REFER to: Transfer Case Control Module (TCCM) .
    No  The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.

  9. K8 CHECK FOR CORRECT GSM (GEAR SHIFT MODULE) OPERATION

    • Ignition OFF.

    • Disconnect and inspect GSM C3245 and all related in-line electrical connectors.

    • Using a good light source, inspect all  disconnected electrical connectors for the following:

      • corrosion - install new connector or terminal and clean the module pins
      • damaged or bent pins - install new terminals or pins
      • pushed-out pins - install new pins as necessary
      • spread terminals - install new terminals as necessary

    • Reconnect GSM C3245 and all related in-line electrical connectors. Make sure they seat and latch correctly.

    • Using the diagnostic scan tool, clear all DTCs.

    • Carry out the GSM self-test.

    Is DTC U0121 still present? 

    Yes  CHECK OASIS for any applicable service articles: TSB, GSB (general service bulletin), SSM (special service message) or FSA (Field Service Action). If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new GSM. REFER to: Gear Shift Module (GSM)  .
    No  The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.
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