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Home >> Ford >> 2020 >> Fusion Titanium Hybrid >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 4 (Automatic Transmission External Controls - 6-Speed Automatic Transmission - 6F35) >> Diagnosis And Testing >> External Controls >> Pinpoint Tests >> Pinpoint Test J : DTC U0121

Pinpoint Test J : DTC U0121

WARNING: This page is about a different variant/trim than selected.
  1. Refer to Module Communications Network for schematic and connector information.

    Normal Operation and Fault Conditions 

    The ABS, GSM and TRCM use information contained in messages on the HS-CAN.

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    GSM U0121:00 Lost Communication With Anti-Lock Brake System (ABS) Control Module "A": No Sub Type Information This DTC sets if the TRCM and/or the GSM does not receive some or all of an expected message from the ABS module.

    Possible Sources 

    • Module communication
    • ABS module
    • GSM
    • TRCM

  2. J1 CHECK THE COMMUNICATION NETWORK

    • Ignition ON.

    • Using the diagnostic scan tool, perform the network test.

    Does the ABS module pass the network test? 

    Yes  For GSM, GO to  J2 For TRCM, GO to  J4
    No  To diagnose the module does not respond to the scan tool, REFER to: Communications Network .

  3. J2 CHECK FOR GSM (GEAR SHIFT MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

    NOTE: If a GSM self-test is performed, the driver door must be closed and locked. A false P166B and/or P081F DTC sets if the driver door is opened or unlocked during the self-test.

    • Clear all DTCs.

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

    Is DTC U0121 present? 

    Yes  GO to  J3
    No  The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

  4. J3 RETRIEVE THE RECORDED DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE GSM (GEAR SHIFT MODULE) SELF-TEST

    • Check for DTCs from the self-test.

    Are any non-network GSM DTCs present? 

    Yes  REFER to the DTC Chart - GSM  and diagnose those DTCs first.
    No  GO to  J6

  5. J4 CHECK FOR TRCM (TRANSMISSION RANGE CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

    • Clear all DTCs.

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

    Is DTC U0121 present? 

    Yes  GO to  J5
    No  The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

  6. J5 RETRIEVE THE RECORDED DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE TRCM (TRANSMISSION RANGE CONTROL MODULE) SELF-TEST

    • Check for DTCs from the self-test.

    Are any non-network TRCM DTCs present? 

    Yes  REFER to DTC Chart - TRCM  and diagnose those DTCs first.
    No  GO to  J6

  7. J6 RETRIEVE THE RECORDED DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE ABS (ANTI-LOCK BRAKE SYSTEM) SELF-TEST

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

    • Check for DTCs from the self-test.

    Is DTC U3000:49 present? 

    Yes  REFER to: Anti-Lock Brake System (ABS) and Stability Control .
    No  GO to  J7

  8. J7 CHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0121 SET IN OTHER MODULES

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

    • Retrieve the DTCs from all modules.

    Is DTC U0121 present in the PCM or IPC module? 

    Yes  CHECK OASIS for any applicable TSBs. If a TSB exists for this concern, discontinue this test and follow TSB instructions. If no TSBs address this concern, Refer to ABS Guided Routine
    No  If the only reporting module is the GSM, INSTALL a new GSM. REFER to: Gear Shift Module (GSM) . If the only reporting module is the TRCM, INSTALL a new TRCM. REFER to: Transmission Range Control Module (TRCM) .
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