CAN COMMUNICATION SYSTEM(for LHD with Central Gateway ECU) Check Bus 3 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the bus 3 CAN main wires and/or CAN branch wires when the resistance between terminals 6 (CA3H) and 21 (CA3L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Detection Item Trouble Area
Resistance between terminals 6 (CA3H) and 21 (CA3L) of central gateway ECU (network gateway ECU) is below 54 Ω.

  • Short in bus 3 CAN main wires

  • Short in bus 3 CAN branch wires

  • Central gateway ECU (network gateway ECU)

  • Radio and display receiver assembly*1

  • Navigation receiver assembly*2

  • No. 4 CAN junction connector
*1: w/ Audio and Visual System (for Radio and Display Type)
*2: w/ Navigation System

WIRING DIAGRAM

B002752E01

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 SHORT IN CAN BUS WIRES (NO. 4 CAN JUNCTION CONNECTOR)


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

      B0027X7C03
      *1 No. 4 CAN Junction Connector - -
      *a

      Rear view of wire harness connector

      (to No. 4 CAN Junction Connector)

      		 - -

    2. Disconnect the No. 4 CAN junction connectors.

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

      Wiring Color
      Code Color (CANH Side) Color (CANL Side) Connect to
      G132 V W

      • Radio and Display Receiver Assembly*1

      • Navigation Receiver Assembly*2
      G133 V W Central Gateway ECU (Network Gateway ECU)
      G135 P W

      *1: w/ Audio and Visual System (for Radio and Display Type)

      *2: w/ Navigation System

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      G132-1 (CANH) - G132-2 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      • Radio and display receiver assembly*1

      • Navigation receiver assembly*2
      G133-1 (CANH) - G133-2 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU)
      G135-1 (CANH) - G135-2 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      *1: w/ Audio and Visual System (for Radio and Display Type)
      *2: w/ Navigation System
      Result
      Proceed to
      OK A
      NG (Central gateway ECU [network gateway ECU] CAN main wire) B
      NG (ECU or sensor CAN branch wires) C

    A

    REPLACE NO. 4 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT IN CAN BUS WIRES (ECU, SENSOR) Click here

    B

  2. CONNECT CONNECTOR


    1. Reconnect the No. 4 CAN junction connectors.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR SHORT IN CAN BUS WIRES (CENTRAL GATEWAY ECU)


    1. B002547C71
      *a

      Front view of wire harness connector

      (to Central Gateway ECU [Network Gateway ECU])

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G128-6 (CA3H) - G128-21 (CA3L) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      G128-19 (CAYH) - G128-20 (CAYL) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

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

  4. CHECK FOR SHORT IN CAN BUS WIRES (ECU, SENSOR)


    1. B0026IYC06
      *a

      Component with harness connected

      (Central Gateway ECU [Network Gateway ECU])

      Reconnect the CAN junction connector.

    2. Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited CAN branch wire is connected.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G128-6 (CA3H) - G128-21 (CA3L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω

      Tech Tips

      If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR CAN BRANCH WIRES OR CONNECTOR