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Main Body ECU Communication Stop Mode [12/2019 - 11/2023]: Procedure

  1. CHECK FOR OPEN IN CAN BUS LINES (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) BRANCH LINE) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the H43 main body ECU (multiplex network body ECU) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H43-5 (CANH) - H43-4 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      GTY846936Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Main Body ECU (Multiplex Network Body ECU))

      Result

      Result 
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) 

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) 
    1. Remove the main body ECU (multiplex network body ECU).

      Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      MB-11 (GND1) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω
      GTY918978Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Main Body ECU (Multiplex Network Body ECU))
      NOTE:

      Perform this inspection with the wire harness connected to the instrument panel junction block assembly.

      Result

      Result 
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (BECU SIGNAL CIRCUIT) 
    1. Reconnect the cable to the negative (-) battery terminal.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      MB-31 (BECU) - Body ground Always 11 to 14 V
      NOTE:

      Perform this inspection with the wire harness connected to the instrument panel junction block assembly.

      GTY918977Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Main Body ECU (Multiplex Network Body ECU))

      Result

      Result 
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (ACC SIGNAL CIRCUIT) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      MB-30 (ACC) - Body ground Ignition switch ON 11 to 14 V
      NOTE:

      Perform this inspection with the wire harness connected to the instrument panel junction block assembly.

      GTY944003Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Main Body ECU (Multiplex Network Body ECU))

      Result

      Result 
      OK
      NG

    Result: 

    NG 

    GO TO LIGHTING (INT) SYSTEM (ACC SIGNAL CIRCUIT) 

    Refer to ACC Signal Circuit [12/2019 - 11/2023]

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (IG SIGNAL CIRCUIT) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      MB-32 (IG) - Body ground Ignition switch ON 11 to 14 V
      NOTE:

      Perform this inspection with the wire harness connected to the instrument panel junction block assembly.

      GTY918976Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Main Body ECU (Multiplex Network Body ECU))

      Result

      Result 
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 

    Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    NG 

    GO TO LIGHTING (INT) SYSTEM (IG SIGNAL CIRCUIT) 

    Refer to IG Signal Circuit [12/2019 - 11/2023]

  6. CHECK HARNESS AND CONNECTOR (BECU SIGNAL CIRCUIT) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the 4C instrument panel junction block assembly connector.
    3. Reconnect the cable to the negative (-) battery terminal.
    4. Measure the voltage according to the value(s) in the table below.
      GTY896410Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Instrument Panel Junction Block Assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      4C-1 - Body ground Always 11 to 14 V

      Result

      Result 
      OK
      NG

    Result: 

    OK 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 

    Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BECU SIGNAL CIRCUIT) 

  7. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the 4B instrument panel junction block assembly connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY914382Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Instrument Panel Junction Block Assembly)

      Standard Resistance

      Tester Connection Condition Specified Condition
      4B-3 - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

      Result

      Result 
      OK
      NG

    Result: 

    OK 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 

    Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT) 

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