CAN COMMUNICATION SYSTEM Main Body ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Main Body ECU Communication Stop Mode

Either condition is met:


  • Communication stop for "Main Body" is indicated on the "Communication Bus Check" screen of the GTS.

    Click here

  • Communication system DTCs (DTCs that start with U) that correspond to "Main Body ECU Communication Stop Mode" in "DTC Combination Table" are output.

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  • Main body ECU (multiplex network body ECU) branch line or connector

  • Power source circuit of main body ECU (multiplex network body ECU) or instrument panel junction block assembly

  • Main body ECU (multiplex network body ECU) or instrument panel junction block assembly ground circuit

  • Main body ECU (multiplex network body ECU) or instrument panel junction block assembly

WIRING DIAGRAM

B00744OE04

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Note


  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

    Click here

  • Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

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  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

    DTC check procedure: Turn the engine switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

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  • Inspect the fuses for circuits related to this system before performing the following procedure.

  • Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.

Tech Tips


  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.

  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

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 O2 main body ECU (multiplex network body ECU) connector.

    3. B0074K2C15
      *a

      Front view of wire harness connector

      (to Main Body ECU (Multiplex Network Body ECU))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      O2-14 (CANH) - O2-13 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result
      OK
      NG

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Remove the main body ECU (multiplex network body ECU).

      Click here

    2. B0075LHC54
      *1

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      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

      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-31 (BECU) - Body ground Always 11 to 14 V
      MB-30 (ACC) - Body ground Engine switch on (ACC) 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 (IG) C
      NG (ACC) D
      NG (GND1) E

    A

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    C

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

    D

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

    E

    CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) Click here

    B

  3. CHECK HARNESS AND CONNECTOR (BECU SIGNAL CIRCUIT)


    1. Disconnect the cable from the negative (-) battery terminal.

    2. Disconnect the 4F instrument panel junction block assembly connector.

    3. Reconnect the cable to the negative (-) battery terminal.

    4. B00761KC02
      *a

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      4F-1 - Body ground Always 11 to 14 V
      Result
      Result
      OK
      NG

    OK

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

  4. 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. B0075HUC02
      *a

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      4B-7 - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR