CAN COMMUNICATION SYSTEM(for LHD) 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.

Symptom 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 receiver assembly

  • Telematics transceiver*

  • No. 8 CAN junction connector

WIRING DIAGRAM

B002DONE08

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.

  • 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


  • 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 SHORT IN CAN BUS WIRE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 8 CAN JUNCTION CONNECTOR)


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

    2. B002CUFC48
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K66-6 (CA3H) - K66-21 (CA3L) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K66-19 (CAYH) - K66-20 (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

  2. CONNECT CONNECTOR


    1. Reconnect the K66 central gateway ECU (network gateway ECU) connector.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR SHORT IN CAN BUS WIRES (NO. 8 CAN JUNCTION CONNECTOR)


    1. B002DGGC01
      *a

      Front view of wire harness connector

      (to No. 8 CAN Junction Connector)
      *b to Central Gateway ECU (Network Gateway ECU) (CA3H and CA3L Terminal)
      *c to Central Gateway ECU (Network Gateway ECU) (CAYH and CAYL Terminal)
      *d to Telematics Transceiver (w/ Telematics Transceiver)
      *e to Radio Receiver Assembly

      Disconnect the No. 8 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K110-1 (CANH) - K110-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU) (CA3H and CA3L terminal)
      K110-2 (CANH) - K110-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU) (CAYH and CAYL terminal)
      K110-3 (CANH) - K110-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Telematics transceiver*
      K110-4 (CANH) - K110-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Radio receiver assembly

      • *: w/ Telematics Transceiver

      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU (network gateway ECU) CAN main wire) B
      NG (ECU or sensor CAN branch wire) C

    A

    REPLACE NO. 8 CAN JUNCTION CONNECTOR

    B

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

    C

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


    1. B002EYMC02
      *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
      K66-6 (CA3H) - K66-21 (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

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

    NG

    REPLACE CORRESPONDING ECU OR SENSOR