CAN COMMUNICATION SYSTEM Open in Bus 3 Main Bus Line

DESCRIPTION

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

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

  • CAN main bus lines or connector

  • Central gateway ECU (network gateway ECU)

  • CAN No. 8 junction connector

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

WIRING DIAGRAM

B001N3JE38
*1 CAYH
*2 CAYL
*3 Central Gateway ECU (Network Gateway ECU)
*4 CAN No. 8 Junction Connector

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.

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  • 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 or any 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 negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

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  • 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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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 MAIN BUS LINES (CAN NO. 8 JUNCTION CONNECTOR)


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

    2. Disconnect the H190 CAN No. 8 junction connector.

    3. B001KUQC12
      *a

      Front view of wire harness connector

      (to CAN No. 8 Junction Connector)
      *b to Central Gateway ECU (Network Gateway ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H190-8 (CANH) - H190-19 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      H190-9 (CANH) - H190-20 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE CAN NO. 8 JUNCTION CONNECTOR

    NG

  2. CHECK FOR OPEN IN CAN MAIN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - CAN NO. 8 JUNCTION CONNECTOR)


    1. Reconnect the H190 CAN No. 8 junction connector.

    2. Disconnect the H188 central gateway ECU (network gateway ECU) connector.

    3. B001MPJC81
      *a

      Front view of wire harness connector

      (to Central gateway ECU (network gateway ECU))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H188-6 (CA3H) - H188-19 (CAYH) Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
      H188-21 (CA3L) - H188-20 (CAYL) Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - CAN NO. 8 JUNCTION CONNECTOR)