CAN COMMUNICATION SYSTEM Open in Bus 3 Main Bus Line

DESCRIPTION

There may be an open circuit in one of the bus 3 main lines when the resistance between terminals 6 (CA3H) and 21 (CA3L) of the network gateway ECU is 70 Ω or higher.

Detection Item Trouble Area
Resistance between terminals 6 (CA3H) and 21 (CA3L) of network gateway ECU is 70 Ω or higher.

  • Bus 3 CAN main wire or connector

  • Network gateway ECU

  • No. 4 CAN junction connector

This malfunction is not related to the lines of a bus 3 branch or to ECUs or sensors connected a bus 3 branch.

WIRING DIAGRAM

A002NOYE10
*a CAYH
*b CAYL
*c No. 4 CAN Junction Connector
*d Network Gateway ECU

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.

  • 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 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 (NO. 4 CAN JUNCTION CONNECTOR)


    1. A002MKYE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 4 CAN Junction Connector)

      Disconnect the No. 4 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      H134-2 (CANH) - H134-8 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Network gateway ECU
      H134-3 (CANH) - H134-9 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

    OK

    REPLACE NO. 4 CAN JUNCTION CONNECTOR

    NG

  2. CONNECT CONNECTOR


    1. Reconnect the H134 No. 4 CAN junction connector.


    NEXT

  3. CHECK FOR OPEN IN CAN BUS WIRE (NETWORK GATEWAY ECU)


    1. A002MXKE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Network Gateway ECU)

      Disconnect the network gateway ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H131-6 (CA3H) - H131-19 (CAYH) Cable disconnected from negative (-) battery terminal Below 1 Ω
      H131-21 (CA3L) - H131-20 (CAYL) Cable disconnected from negative (-) battery terminal Below 1 Ω
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    A

    REPLACE NETWORK GATEWAY ECU Click here

    B

    REPLACE NETWORK GATEWAY ECU Click here

    C

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NETWORK GATEWAY ECU - NO. 4 CAN JUNCTION CONNECTOR)