CAN COMMUNICATION SYSTEM(for LHD) Check Bus 4 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the bus 4 CAN main wires and/or CAN branch wires when the resistance between terminals 22 (CA2H) and 7 (CA2L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom Trouble Area
Resistance between terminals 22 (CA2H) and 7 (CA2L) of central gateway ECU (network gateway ECU) is below 54 Ω.

  • Short in bus 4 CAN main wires

  • Short in bus 4 CAN branch wires

  • Central gateway ECU (network gateway ECU)

  • ECM

  • Brake actuator assembly (skid control ECU)

  • Roll rate and vertical acceleration sensor (yaw rate sensor)

  • Driving support ECU assembly*1

  • Torque vectoring differential ECU assembly

  • No. 2 CAN junction terminal

  • No. 6 CAN junction connector

  • No. 7 CAN junction connector

  • No. 10 CAN junction connector

WIRING DIAGRAM

B002DQVE05

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

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.

    Click here

  • 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

  • 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 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

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

    Click here

  • Before replacing the ECM, refer to Service Bulletin.

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 (ECM - NO. 7 CAN JUNCTION CONNECTOR)


    1. B002C76C03
      *a

      Front view of wire harness connector

      (to ECM)

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

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A13-11 (CANP) - A13-12 (CANN) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

  2. CONNECT CONNECTOR


    1. Reconnect the A13 ECM connector.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR SHORT IN CAN BUS WIRE (NO. 2 CAN JUNCTION TERMINAL - NO. 10 CAN JUNCTION CONNECTOR)


    1. B002ET0C69
      *a

      Front 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
      U57-3 (CANH) - U57-2 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 2 CAN JUNCTION TERMINAL

    NG

  4. CONNECT CONNECTOR


    1. Reconnect the U57 No. 2 CAN junction terminal connector.

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK FOR SHORT IN CAN BUS WIRE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 7 CAN JUNCTION CONNECTOR)


    1. B002CUFC49
      *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
      K66-22 (CA2H) - K66-7 (CA2L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

  6. CONNECT CONNECTOR


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

      Result
      Proceed to
      NEXT

    NEXT

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


    1. B002DQNC40
      *a

      Front view of wire harness connector

      (to No. 7 CAN Junction Connector)
      *b to ECM
      *c to Central Gateway ECU (Network Gateway ECU)
      *d to No. 6 CAN Junction Connector

      Disconnect the No. 7 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
      K109-1 (CANH) - K109-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
      K109-4 (CANH) - K109-15 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Central gateway ECU (network gateway ECU)
      K109-5 (CANH) - K109-16 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 6 CAN Junction Connector
      Result
      Result Proceed to
      OK A
      NG (ECM CAN main wire) B
      NG (No. 6 CAN junction connector CAN main wire) C
      NG (Central gateway ECU (network gateway ECU) CAN branch wire) D

    A

    REPLACE NO. 7 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - ECM)

    D

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

    C

  8. CONNECT CONNECTOR


    1. Reconnect the K109 No. 7 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

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


    1. B002DQNC43
      *a

      Front view of wire harness connector

      (to No. 6 CAN Junction Connector)
      *b to Driving Support ECU Assembly (w/ Pre-crash Safety System)
      *c to No. 10 CAN Junction Connector
      *d to Brake Actuator Assembly (Skid Control ECU)
      *e to Roll Rate and Vertical Acceleration Sensor (Yaw Rate Sensor)
      *f to No. 7 CAN Junction Connector

      Disconnect the 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 Connected to
      K108-1 (CANH) - K108-12 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Driving support ECU assembly*1
      K108-2 (CANH) - K108-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 10 CAN junction connector
      K108-3 (CANH) - K108-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Brake actuator assembly (skid control ECU)
      K108-4 (CANH) - K108-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Roll rate and vertical acceleration sensor (yaw rate sensor)
      K108-5 (CANH) - K108-16 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 7 CAN junction connector

      • *1: w/ Pre-crash Safety System

      Result
      Result Proceed to
      OK A
      NG (No. 7 CAN junction connector CAN main wire) B
      NG (No. 10 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 6 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 6 CAN JUNCTION CONNECTOR - NO. 7 CAN JUNCTION CONNECTOR)

    D

    GO TO STEP 12 Click here

    C

  10. CONNECT CONNECTOR


    1. Reconnect the K108 No. 6 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

  11. CHECK FOR SHORT IN CAN BUS WIRES (NO. 10 CAN JUNCTION CONNECTOR)


    1. B002DQNC44
      *a

      Front view of wire harness connector

      (to No. 10 CAN Junction Connector)
      *b to No. 2 CAN Junction Terminal
      *c to No. 6 CAN Junction Connector
      *d to Torque Vectoring Differential ECU Assembly

      Disconnect the No. 10 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
      U55-5 (CANH) - U55-16 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 2 CAN junction terminal
      U55-6 (CANH) - U55-17 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 6 CAN junction connector
      U55-7 (CANH) - U55-18 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Torque vectoring differential ECU assembly
      Result
      Result Proceed to
      OK A
      NG (No. 6 CAN junction connector CAN main wire) B
      NG (No. 2 CAN junction terminal CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 10 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 6 CAN JUNCTION CONNECTOR - NO. 10 CAN JUNCTION CONNECTOR)

    C

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 10 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL)

    D

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


    1. B002EYMC03
      *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
      K66-22 (CA2H) - K66-7 (CA2L) 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