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.

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

  • CAN main bus line or connector

  • Network gateway ECU

  • No. 6 CAN junction connector

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

WIRING DIAGRAM

B007XL6E05
*1 CAYH
*2 CAYL
*3 No. 6 CAN Junction Connector
*4 Network Gateway ECU

CAUTION / NOTICE / HINT

Note


  • 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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  • 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.

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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 at least 31 seconds.

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

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Tech Tips


  • Operating the engine switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • 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 LINES (NO. 6 CAN JUNCTION CONNECTOR)


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

    2. B007X47C32
      *a

      Front view of wire harness connector

      (to No. 6 CAN Junction Connector)
      *b to Network Gateway ECU

      Disconnect the J98 No. 6 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      J98-7 (CANH) - J98-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Network gateway ECU
      J98-11 (CANH) - J98-22 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Network gateway ECU
      Result
      Result
      OK
      NG

    OK

    REPLACE NO. 6 CAN JUNCTION CONNECTOR

    NG

  2. CHECK FOR OPEN IN CAN BUS LINES (NETWORK GATEWAY ECU - NO. 6 CAN JUNCTION CONNECTOR)


    1. Reconnect the J98 No. 6 CAN junction connector.

    2. B007YYOC64
      *a

      Front view of wire harness connector

      (to Network Gateway ECU)

      Disconnect the J75 network gateway ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      J75-6 (CA3H) - J75-19 (CAYH) Cable disconnected from negative (-) battery terminal Below 1 Ω
      J75-21 (CA3L) - J75-20 (CAYL) Cable disconnected from negative (-) battery terminal Below 1 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE NETWORK GATEWAY ECU Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NETWORK GATEWAY ECU - NO. 6 CAN JUNCTION CONNECTOR)