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DTC P1779-49: Gear Shift Control Module Backup Power Supply Internal Electronic Failure [11/2021 - ]: Procedure

  1. CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR - SHIFT ACTUATOR ECU) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Disconnect the B77 shift control actuator assembly (shift actuator ECU) connector.

      Procedure1

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G102-19 (BUA) - Body ground Always Below 1 V
      G102-9 (BUAE) - Body ground Always Below 1 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Connect the shift control actuator assembly (shift actuator ECU) connector.
    5. Connect the integration control supply (integrated capacitor) connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR - SHIFT CONTROL ECU) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Disconnect the D39 transmission floor shift assembly (shift control ECU) connector.

      Procedure1

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G102-1 (BUSE) - Body ground Always Below 1 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Connect the transmission floor shift assembly (shift control ECU) connector.
    5. Connect the integration control supply (integrated capacitor) connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR - POWER DISTRIBUTION BOX ASSEMBLY) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Disconnect the 9C power distribution box assembly connector.

      Procedure1

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G102-10 (BUE2) - Body ground Always Below 1 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Connect the power distribution box assembly connector.
    5. Connect the integration control supply (integrated capacitor) connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. INSPECT POWER DISTRIBUTION BOX ASSEMBLY 

    Pre-procedure1

    1. Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.

      Refer to REMOVAL [11/2021 - ]

      Procedure1

    2. Measure the resistance according to the value(s) in the table below.
      GTY1065495Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Power Distribution Box Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      9C-27 or MB-25 (SBAT) - Other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. Install the main body ECU (multiplex network body ECU) to the power distribution box assembly.

      Refer to INSTALLATION [11/2021 - ]

    Result: 

    NG 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR - DOOR LOCK ASSEMBLY) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Disconnect the E34 front door lock with motor assembly LH connector.
    3. Disconnect the E13 front door lock with motor assembly RH connector.
    4. Disconnect the F23 rear door lock with motor assembly LH connector.
    5. Disconnect the F9 rear door lock with motor assembly RH connector.

      Procedure1

    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G102-20 (BUA2) - Body ground Always Below 1 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    7. Connect the rear door lock with motor assembly RH connector.
    8. Connect the rear door lock with motor assembly LH connector.
    9. Connect the front door lock with motor assembly RH connector.
    10. Connect the front door lock with motor assembly LH connector.
    11. Connect the integration control supply (integrated capacitor) connector.

    Result: 

    OK 

    REPLACE INTEGRATION CONTROL SUPPLY (INTEGRATED CAPACITOR). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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