CAN COMMUNICATION SYSTEM(for LHD with Central Gateway ECU) Main Body ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Main Body ECU Communication Stop Mode

Either condition is met:


  • "Main Body" is not displayed on "CAN Bus Check".

    Click here

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

    Click here


  • Power source or inside main body ECU (multiplex network body ECU)

  • Main body ECU (multiplex network body ECU) CAN branch wire or connector

  • Main body ECU (multiplex network body ECU)

  • Instrument panel junction block assembly

WIRING DIAGRAM

Figure 1. w/o Seat Memory

A01V7WPE02

Figure 2. w/ Seat Memory

A01V7MBE07

CAUTION / NOTICE / HINT

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 ignition switch off and leave the vehicle for 1 minute or more without operating the key, 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 ignition switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work.

    Click here

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

  • DTC check procedure: Wait 20 seconds after turning the ignition switch ACC or ON.

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

    Click here

  • When replacing the main body ECU (multiplex network body ECU), make sure to replace it with a new one.

Tech Tips


  • Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. CHECK FOR OPEN IN CAN BUS WIRE (MAIN BODY ECU CAN BRANCH WIRE)


    1. A01V7E0C04
      *a

      Rear view of wire harness connector

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

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

    2. Disconnect the 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
      G78-14 (CANH) - G78-13 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result Proceed to
      OK (w/ Seat Memory) A
      OK (w/o Seat Memory) B
      NG C

    B

    CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BATTERY AND BODY GROUND) Click here

    C

    REPAIR OR REPLACE MAIN BODY ECU CAN BRANCH WIRE OR CONNECTOR (CANH, CANL)

    A

  2. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BATTERY AND BODY GROUND)


    1. A01V8QRC04
      *a

      Front view of wire harness connector

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

      Connect the cable to the negative (-) battery terminal.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

      Click here

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

      Click here

    3. Reconnect the 3A, 3C and 3D instrument panel junction block assembly connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A-30 (BECU) - Body ground Always 11 to 14 V
      A-32 (IG) - Body ground Ignition switch ON 11 to 14 V
      A-29 (ACC) - Body ground Ignition switch ACC 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A-11 (GND1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

  3. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BATTERY AND BODY GROUND)


    1. Disconnect the instrument panel junction block assembly connectors.

      A01V7EAC01
      *a

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

      		 - -

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3A-1 - Body ground Always 11 to 14 V
      3D-41 - Body ground Always 11 to 14 V
      3C-45 - Body ground Ignition switch ACC 11 to 14 V
      3D-40 - Body ground Ignition switch ON 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3D-9 - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  4. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BATTERY AND BODY GROUND)


    1. A01V8QRC04
      *a

      Front view of wire harness connector

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

      Connect the cable to the negative (-) battery terminal.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

      Click here

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

      Click here

    3. Reconnect the 3A, 3B, 3C and 3D instrument panel junction block assembly connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A-30 (BECU) - Body ground Always 11 to 14 V
      A-32 (IG) - Body ground Ignition switch ON

      11 to 14 V*1

      10.5 to 16 V*2
      A-29 (ACC) - Body ground Ignition switch ACC 11 to 14 V
      *1: w/o Stop and Start System
      *2: w/ Stop and Start System

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A-11 (GND1) - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK A
      NG (w/o Stop and Start System) B
      NG (w/ Stop and Start System) C

    A

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

    C

    CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BATTERY AND BODY GROUND) Click here

    B

  5. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BATTERY AND BODY GROUND)


    1. Disconnect the instrument panel junction block assembly connectors.

      A01V6Y5C01
      *a

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

      		 - -

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3A-1 - Body ground Always 11 to 14 V
      3B-16 - Body ground Always 11 to 14 V
      3C-45 - Body ground Ignition switch ACC 11 to 14 V
      3D-40 - Body ground Ignition switch ON 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3D-9 - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BATTERY AND BODY GROUND)


    1. Disconnect the instrument panel junction block assembly connectors.

      A01V6Y5C01
      *a

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

      		 - -

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3A-1 - Body ground Always 11 to 14 V
      3B-16 - Body ground Always 11 to 14 V
      3C-45 - Body ground Ignition switch ACC 11 to 14 V
      3D-40 - Body ground Ignition switch ON 10.5 to 16 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3D-9 - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK A
      NG (3D-40 terminal) B
      NG (Except 3D-40 terminals) C

    A

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    B

    GO TO STOP AND START SYSTEM for 2WW: GO TO STOP AND START SYSTEM Click here
    GO TO STOP AND START SYSTEM for 3ZR-FAE: GO TO STOP AND START SYSTEM Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR