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 is below 54 Ω.

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

  • Short in bus 3 CAN main wires

  • Short in bus 3 CAN branch wires

  • Central gateway ECU

  • Multi-media module receiver assembly*1

  • Bus buffer ECU*2

  • Radio and display receiver assembly*3

  • No. 5 CAN junction connector

  • No. 6 CAN junction connector

  • No. 2 CAN junction terminal

WIRING DIAGRAM

A01XANPE02

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 (CENTRAL GATEWAY ECU - NO. 5 CAN JUNCTION CONNECTOR)


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

    2. A01X8HUE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Central Gateway ECU)

      Disconnect the central gateway ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E145-6 (CA3H) - E145-21 (CA3L) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

    OK

    REPLACE CENTRAL GATEWAY ECU Click here

    NG

  2. CONNECT CONNECTOR


    1. Reconnect the E145 central gateway ECU connector.


    NEXT

  3. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 CAN JUNCTION TERMINAL - NO. 6 CAN JUNCTION CONNECTOR)


    1. A01XAX2E02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 2 CAN Junction Terminal)

      Disconnect the No. 2 CAN junction terminal connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F98-3 (CANH) - F98-2 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

    OK

    REPLACE NO. 2 CAN JUNCTION TERMINAL

    NG

  4. CONNECT CONNECTOR


    1. Reconnect the F98 No. 2 CAN junction terminal connector.


    NEXT

  5. CHECK FOR SHORT IN CAN BUS WIRES (NO. 5 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 5 CAN junction connector.

      A01X64HE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 5 CAN Junction Connector)

      		 *b to Central Gateway ECU
      *c to Bus Buffer ECU (w/ Bus Buffer ECU) *d

      • to Multi-media Module Receiver Assembly (for Multi-media Module Receiver Type)

      • to Radio and Display Receiver Assembly (for Radio and Display Type)
      *e to No. 6 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
      E152-8 (CANH) - E152-19 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU
      E152-9 (CANH) - E152-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Bus buffer ECU*1
      E152-10 (CANH) - E152-21 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      • Multi-media module receiver assembly*2

      • Radio and display receiver assembly*3
      E152-11 (CANH) - E152-22 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 6 CAN junction connector

      • *1: w/ Bus Buffer ECU

      • *2: for Multi-media Module Receiver Type

      • *3: Radio and Display Type

      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU CAN main wire) B
      NG (No. 6 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 5 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU)

    D

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

    C

  6. CONNECT CONNECTOR


    1. Reconnect the E152 No. 5 CAN junction connector.


    NEXT

  7. CHECK FOR SHORT IN CAN BUS WIRES (NO. 6 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 6 CAN junction connector.

      A01X9G2E01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 6 CAN Junction Connector)

      		 *b to No. 5 CAN Junction Connector
      *c to No. 2 CAN Junction Terminal - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      F99-6 (CANH) - F99-17 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 5 CAN junction connector
      F99-7 (CANH) - F99-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 2 CAN junction terminal
      Result
      Result Proceed to
      OK A
      NG (No. 5 CAN junction connector CAN main wire) B
      NG (No. 2 CAN junction terminal CAN main wire) C

    A

    REPLACE NO. 6 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 6 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR)

    C

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 6 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL)

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


    1. A01X1AQE02
      Text in Illustration
      *a

      Component with harness connected

      (Central 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
      E145-6 (CA3H) - E145-21 (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.


    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

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