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Main Body ECU Communication Stop Mode [06/2018 - ]: 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 G37 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
      G37-5 (CANH) - G37-4 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      GTY784499Courtesy 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 (POWER SOURCE CIRCUIT) 
    1. Remove the main body ECU (multiplex network body ECU).

      Refer to REMOVAL [06/2018 - 08/2021] , or refer to REMOVAL [08/2021 - 09/2022] , or refer to REMOVAL [09/2022 - ]

    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
      GTY591506Courtesy 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.

    3. Reconnect the cable to the negative (-) battery terminal.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      MB-30 (ACC) - Body ground Engine switch on (ACC) 11 to 14 V
      MB-31 (BECU) - Body ground Always 11 to 14 V
      MB-32 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      NOTE:

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

      Result

      Result Proceed to
      OK A
      NG (BECU) B
      NG (ACC) C
      NG (IG) D
      NG (GND1) E

    Result: 

    A 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022]  , or refer to  REMOVAL [09/2022 - ] 

    Result: 

    C 

    GO TO LIGHTING (INT) SYSTEM (ACC SIGNAL CIRCUIT). Refer to  ACC Signal Circuit [06/2018 - ] 

    Result: 

    D 

    GO TO LIGHTING (INT) SYSTEM (IG SIGNAL CIRCUIT). Refer to  IG Signal Circuit [06/2018 - ] 

    Result: 

    E 

    See step  4

    Result: 

    B 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (BECU SIGNAL CIRCUIT) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the 3F 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.
      GTY792738Courtesy 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
      3F-1 - Body ground Always 11 to 14 V

      Result

      Result 
      OK
      NG

    Result: 

    OK 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022]  , or refer to  REMOVAL [09/2022 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BECU SIGNAL CIRCUIT) 

  4. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the 3D instrument panel junction block assembly connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY813267Courtesy 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
      3D-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 [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022]  , or refer to  REMOVAL [09/2022 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT) 

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