CAN COMMUNICATION SYSTEM(for RHD) 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 indicated on the "Bus Check" screen 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.

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

  • Power source circuit of main body ECU (multiplex network body ECU) or cowl side junction block LH

  • Main body ECU (multiplex network body ECU) ground circuit or cowl side junction block LH ground circuit

  • Main body ECU (multiplex network body ECU) or cowl side junction block LH

WIRING DIAGRAM

B002BOVE08

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 power 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 (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the auxiliary battery terminal notice before proceeding with work Click here.

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

  • If the main body ECU (multiplex network body ECU) is replaced, refer to the Service Bulletin.

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

  • DTC check procedure: Turn the power switch on (IG) and turn the blind spot monitor main switch on, and then wait approximately 12 seconds or more.

  • 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.

Tech Tips


  • Operating the power 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. A000SB4E02
      Text in Illustration
      *a

      Rear view of wire harness connector

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

      Disconnect the cable from the negative (-) auxiliary 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
      N12-14 (CANH) - N12-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

    NG

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

    OK

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


    1. A000PM1E03
      Text in Illustration
      *a

      Front view of wire harness connector

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

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

      Note

      When connecting 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 cowl side junction block LH connectors.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A-30 (BECU) - Body ground Power switch off 11 to 14 V
      A-31 (ALTB) - Body ground Power switch off 11 to 14 V
      A-29 (ACC) - Body ground Power switch on (ACC) 11 to 14 V
      A-32 (IG) - Body ground Power switch on (IG) 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

    OK

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

    NG

  3. CHECK HARNESS AND CONNECTOR (COWL SIDE JUNCTION BLOCK LH - BATTERY AND BODY GROUND)


    1. Disconnect the cowl side junction block LH connectors.

      A000SQIE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Cowl Side Junction Block LH)

      		 - -

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      5D-32 - Body ground Power switch off 11 to 14 V
      5E-1 - Body ground Power switch off 11 to 14 V
      5F-1 - Body ground Power switch off 11 to 14 V
      5B-19 - Body ground Power switch on (ACC) 11 to 14 V
      5A-35 - Body ground Power switch on (IG) 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      5B-1 - Body ground Always Below 1 Ω

    OK

    REPLACE COWL SIDE JUNCTION BLOCK LH Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR