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DTC P1779-96: Gear Shift Control Module Backup Power Supply Component Internal Failure [11/2021 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus NX 350h, 2024 Lexus NX 350h, 2023 Lexus NX 350h, and 2022 Lexus NX 350h. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FREEZE FRAME DATA (GEAR SHIFT CONTROL MODULE BACKUP SIGNAL STATUS) 

    Pre-procedure1

    1. Turn the ignition switch to ON.

      Procedure1

    2. Read the freeze frame data of DTC P1779-96.

      Powertrain > Hybrid Control > DTC (P1779-96) > Freeze Frame Data 

      Tester Display
      Gear Shift Control Module Backup Signal Status

      Result

      Result Proceed to
      The value of Gear Shift Control Module Backup Signal Status is not Capacitor External Failure A
      The value of Gear Shift Control Module Backup Signal Status is Capacitor External Failure B

      Post-procedure1

    3. Turn the ignition switch off.

    Result: 

    B 

    See step  16

    Result: 

    A 

    See step  2

  2. CHECK FREEZE FRAME DATA (GEAR SHIFT CONTROL MODULE BACKUP SIGNAL STATUS) 

    Pre-procedure1

    1. Turn the ignition switch to ON.

      Procedure1

    2. Read the freeze frame data of DTC P1779-96.

      Powertrain > Hybrid Control > DTC (P1779-96) > Freeze Frame Data 

      Tester Display
      Gear Shift Control Module Backup Signal Status

      Result

      Result Proceed to
      The value of Gear Shift Control Module Backup Signal Status is not Capacitor External Failure (Backup Possible) A
      The value of Gear Shift Control Module Backup Signal Status is Capacitor External Failure (Backup Possible) B

      Post-procedure1

    3. Turn the ignition switch off.

    Result: 

    B 

    See step  10

    Result: 

    A 

    See step  3

  3. CONFIRM VEHICLE SPECIFICATION 
    1. Choose the model to be inspected.

      Result

      Result Proceed to
      w/o Advanced Park System A
      w/ Advanced Park System B

    Result: 

    A 

    See step  5

    Result: 

    B 

    See step  4

  4. CHECK FREEZE FRAME DATA (GEAR SHIFT CONTROL MODULE BACKUP SIGNAL STATUS) 

    Pre-procedure1

    1. Turn the ignition switch to ON.

      Procedure1

    2. Read the freeze frame data of DTC P1779-96.

      Powertrain > Hybrid Control > DTC (P1779-96) > Freeze Frame Data 

      Tester Display
      Gear Shift Control Module Backup Signal Status

      Result

      Result Proceed to
      The value of Gear Shift Control Module Backup Signal Status is not Capacitor External Failure (Brake Factor) A
      The value of Gear Shift Control Module Backup Signal Status is Capacitor External Failure (Brake Factor) B

      Post-procedure1

    3. Turn the ignition switch off.

    Result: 

    B 

    See step  7

    Result: 

    A 

    See step  5

  5. CLEAR DTC 

    Pre-procedure1

    1. Turn the ignition switch off and wait for 10 minutes or more.
    2. Turn the ignition switch to ON.

      Procedure1

    3. Clear the DTCs.

      Powertrain > Hybrid Control > Clear DTCs 

      Result

      Proceed to
      NEXT

      Post-procedure1

    4. Turn the ignition switch off.

    Result: 

    NEXT 

    See step  6

  6. CHECK DTC OUTPUT (PERFORM A REPRODUCTION TEST) 

    Pre-procedure1

    1. Turn the ignition switch to ON and wait for 10 seconds or more.
    2. Turn the ignition switch off and wait for 10 minutes or more.
    3. Turn the ignition switch to ON.

      Procedure1

    4. Check for DTCs.

      Powertrain > Hybrid Control > Trouble Codes 

      Result

      Result Proceed to
      P1779-96 is output A
      P1779-96 is not output B

      Post-procedure1

    5. Turn the ignition switch off.

    Result: 

    A 

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

    Result: 

    B 

    CHECK FOR INTERMITTENT PROBLEMS 

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ]

    Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [11/2021 - ]

  7. CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR - SWITCHING CIRCUIT) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Disconnect the G132 second power supply remote parking circuit (switching circuit) connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      G102-6 (BUA3) - G132-5 (B1A2) Always Below 1 Ω
      G102-8 (BUE3) - G132-3 (B1E2) Always Below 1 Ω
      G102-6 (BUA3) or G132-5 (B1A2) - Body ground and other terminals Always 10 kΩ or higher
      G102-8 (BUE3) or G132-3 (B1E2) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Connect the second power supply remote parking circuit (switching circuit) connector.
    5. Connect the integration control supply (integrated capacitor) connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (SWITCHING CIRCUIT - NO. 1 SKID CONTROL ECU) 

    Pre-procedure1

    1. Disconnect the G132 and G134 second power supply remote parking circuit (switching circuit) connectors.
    2. Disconnect the A39 No. 1 skid control ECU (brake booster with master cylinder assembly) connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      G134-2 (BOA) - A39-15 (BS) Always Below 1 Ω
      G132-8 (BOE) - A39-14 (+BI1) Always Below 1 Ω
      G134-2 (BOA) or A39-15 (BS) - Body ground and other terminals Always 10 kΩ or higher
      G132-8 (BOE) or A39-14 (+BI1) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Connect the No. 1 skid control ECU (brake booster with master cylinder assembly) connector.
    5. Connect the second power supply remote parking circuit (switching circuit) connectors.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. INSPECT SECOND POWER SUPPLY REMOTE PARKING CIRCUIT (SWITCHING CIRCUIT) 
    1. Inspect the second power supply remote parking circuit (switching circuit).

      HINT: 

      Refer to PROCEDURE - Step 3 [11/2021 - 03/2024] , or refer to PROCEDURE - Step 3 [03/2024 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    REPLACE SECOND POWER SUPPLY REMOTE PARKING CIRCUIT (SWITCHING CIRCUIT). Refer to  REMOVAL [11/2021 - ] 

  10. 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 resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G102-10 (BUE2) - 9C-27 Always Below 1 Ω
      G102-10 (BUE2) or 9C-27 - Body ground and other terminals Always 10 kΩ or higher

      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  11

  11. 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.
      GTY1065493Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Power Distribution Box Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      9C-27 - MB-25 (SBAT) Always Below 1 Ω
      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.

    Result: 

    NG 

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

    Result: 

    OK 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR - FRONT DOOR LOCK WITH MOTOR ASSEMBLY LH) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Disconnect the E34 front door lock with motor assembly LH connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      G102-20 (BUA2) - E34-3 (BUB1) Always Below 1 Ω
      G102-20 (BUA2) or E34-3 (BUB1) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Connect the front door lock with motor assembly LH connector.
    5. Connect the integration control supply (integrated capacitor) connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR - FRONT DOOR LOCK WITH MOTOR ASSEMBLY RH) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Disconnect the E13 front door lock with motor assembly RH connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      G102-20 (BUA2) - E13-3 (BUB2) Always Below 1 Ω
      G102-20 (BUA2) or E13-3 (BUB2) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Connect the front door lock with motor assembly RH connector.
    5. Connect the integration control supply (integrated capacitor) connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR - REAR DOOR LOCK WITH MOTOR ASSEMBLY LH) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Disconnect the F23 rear door lock with motor assembly LH connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      G102-20 (BUA2) - F23-3 (BUB4) Always Below 1 Ω
      G102-20 (BUA2) or F23-3 (BUB4) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Connect the rear door lock with motor assembly LH connector.
    5. Connect the integration control supply (integrated capacitor) connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  15

  15. CHECK HARNESS AND CONNECTOR (INTEGRATED CAPACITOR - REAR DOOR LOCK WITH MOTOR ASSEMBLY RH) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Disconnect the F9 rear door lock with motor assembly RH connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      G102-20 (BUA2) - F9-3 (BUB3) Always Below 1 Ω
      G102-20 (BUA2) or F9-3 (BUB3) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Connect the rear door lock with motor assembly RH connector.
    5. 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 

  16. CHECK HARNESS AND CONNECTOR (BR TERMINAL INPUT VOLTAGE) 

    Pre-procedure1

    1. Disconnect the G102 integration control supply (integrated capacitor) connector.
    2. Turn the ignition switch to ON.

      Procedure1

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      G102-14 (BR) - Body ground Ignition switch to ON 8 to 14 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Turn the ignition switch off.
    5. Connect the integration control supply (integrated capacitor) connector.

    Result: 

    NG 

    See step  19

    Result: 

    OK 

    See step  17

  17. 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 resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G102-1 (BUSE) - D39-13 (BUB) Always Below 1 Ω
      G102-1 (BUSE) or D39-13 (BUB) - Body ground and other terminals Always 10 kΩ or higher

      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  18

  18. 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 resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G102-19 (BUA) - B77-6 (MA2) Always Below 1 Ω
      G102-9 (BUAE) - B77-8 (BUB1) Always Below 1 Ω
      G102-19 (BUA) or B77-6 (MA2) - Body ground and other terminals Always 10 kΩ or higher
      G102-9 (BUAE) or B77-8 (BUB1) - Body ground and other terminals Always 10 kΩ or higher

      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: 

    OK 

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

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  19. 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 resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G102-14 (BR) - D39-20 (BUBO) Always Below 1 Ω
      G102-14 (BR) or D39-20 (BUBO) - Body ground and other terminals Always 10 kΩ or higher

      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: 

    OK 

    REPLACE TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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