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DTC U1176-87: Lost Communication with Gear Shift Control Module "A" (ch2) Missing Message [11/2021 - ]: Procedure

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  1. CHECK DTC OUTPUT (TRANSMISSION) 

    Pre-procedure1

    1. Turn the ignition switch to ON.

      Procedure1

    2. Check for DTCs.

      Result

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

      Post-procedure1

    3. Turn the ignition switch off.

    Result: 

    A 

    GO TO DTC CHART (P1779-96). Refer to  DTC P1779-96: Gear Shift Control Module Backup Power Supply Component Internal Failure [11/2021 - ] 

    Result: 

    B 

    See step  2

  2. CHECK DTC OUTPUT (HEALTH CHECK) 
    1. Enter the following menus: Health Check.
    2. Check for DTCs.

      Result

      Result Proceed to
      Only U1176-87 is output. A
      DTCs other than U1176-87 are not output B
    3. Turn the engine switch off.

    Result: 

    B 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2021 - ] 

    Result: 

    A 

    See step  3

  3. CHECK TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU) (BATT TERMINAL VOLTAGE) 
    1. Measure the voltage according to the value(s) in the table below.
      GTY1065827Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Transmission Floor Shift Assembly (Shift Control ECU))

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      D39-2 (BATT) - D39-9 (E1) Ignition switch off 11 to 14 V

      HINT: 

      As there might be an intermittent malfunction in the transmission floor shift assembly (shift control ECU) power source circuit, inspect the following even if the measured voltage is as specified:

      • Installation condition of fuse(s) (before removing fuse(s)) (BATT circuit)
      • Fuse condition (before and after removing fuse(s)) (BATT circuit)
      • Connection condition of connectors (BATT circuit)
      • Wire harness condition (BATT circuit)
      • Wire harness condition (GND circuit)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (SHIFT CONTROL ECU POWER SOURCE CIRCUIT) 

    Result: 

    OK 

    See step  4

  4. CHECK TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU) (IGR, IGP TERMINAL VOLTAGE) 
    1. Turn the ignition switch to ON.
    2. Measure the voltage according to the value(s) in the table below.
      GTY1065092Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Transmission Floor Shift Assembly (Shift Control ECU))

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      D39-3 (IGR) - D39-9 (E1) Ignition switch ON 11 to 14 V
      D39-1 (IGP) - D39-9 (E1) Ignition switch ON 11 to 14 V

      HINT: 

      As there might be an intermittent malfunction in the transmission floor shift assembly (shift control ECU) power source circuit, inspect the following even if the measured voltage is as specified:

      • Installation condition of fuse(s) (before removing fuse(s)) (IGR, IGP circuits)
      • Fuse condition (before and after removing fuse(s)) (IGR, IGP circuits)
      • Connection condition of connectors (IGR, IGP circuits)
      • Wire harness condition (IGR, IGP circuits)
      • Wire harness condition (GND circuit)

      Result

      Proceed to
      OK
      NG
    3. Turn the ignition switch OFF.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (SHIFT CONTROL ECU POWER SOURCE CIRCUIT) 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU) - ECM) 
    1. Disconnect the B51 ECM connector.
      NOTE:
      • Before disconnecting the connector, check that it is not loose or disconnected.
      • Check that each connector between the ECM and transmission floor shift assembly (shift control ECU) is not loose or disconnected.
    2. Disconnect the D39 transmission floor shift assembly connector.
      NOTE:
      • Before disconnecting the connector, check that it is not loose or disconnected.
      • Check the terminals of the connector for deformation and corrosion.
    3. Disconnect the B77 shift control actuator assembly connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      B51-49 (CAN+) - D39-21 (CA3H) Ignition switch off Below 1 Ω
      B51-48 (CAN-) - D39-6 (CA3L) Ignition switch off Below 1 Ω
      D39-21 (CA3H) - Body ground and other terminals Ignition switch off 10 kΩ or higher
      D39-6 (CA3L) - Body ground and other terminals Ignition switch off 10 kΩ or higher
      NOTE:

      Make sure that each connector between the ECM and transmission floor shift assembly (shift control ECU) is not loose or disconnected and its terminals are not deformed or corroded.

      Result

      Proceed to
      OK
      NG
    5. Connect the B77 shift control actuator assembly connector.
    6. Connect the D39 transmission floor shift assembly connector.
    7. Connect the B51 ECM 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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