CAN COMMUNICATION SYSTEM(for LHD with Central Gateway ECU) Check Bus 2 Line for Short to +B

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and +B when no resistance exists between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.

Detection Item Trouble Area
No resistance exists between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.

  • Short to +B in bus 2 CAN main wires

  • Short to +B in bus 2 CAN branch wires

  • ECM

  • Combination meter assembly

  • Central gateway ECU (network gateway ECU)

  • Brake actuator assembly (skid control ECU)

  • Spiral with sensor cable sub-assembly (steering angle sensor)

  • Air conditioning amplifier assembly*1

  • Airbag sensor assembly

  • Certification ECU (smart key ECU assembly)*2

  • 4 wheel drive control ECU*3

  • Headlight leveling ECU assembly*4

  • Engine stop and start ECU*5

  • No. 1 CAN junction connector

  • No. 2 CAN junction connector
*1: for Automatic Air Conditioning System or Manual Air Conditioning System
*2: w/ Entry and Start System
*3: for 4WD
*4: for LED Headlight or w/ Headlight Cleaner System
*5: w/ Stop and Start System

WIRING DIAGRAM

B0025IIE01
B00268HE01

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 TO B+ IN CAN BUS WIRE (NO. 2 CAN JUNCTION CONNECTOR)


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

      B0025W1C03
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Certification ECU (Smart Key ECU Assembly) (w/ Entry and Start System) *d to 4 Wheel Drive Control ECU (for 4WD)
      *e to ECM *f to No. 1 CAN Junction Connector
      *g

      • to Air Conditioning Amplifier Assembly (for Automatic Air Conditioning System)

      • to Air Conditioning Amplifier Assembly (for Manual Air Conditioning System)

      		 - -

    2. Disconnect the No. 2 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      G68-3 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Certification ECU (smart key ECU assembly)*1
      G68-13 (CANL) - G8-16 (BAT)
      G68-4 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher 4 wheel drive control ECU*2
      G68-14 (CANL) - G8-16 (BAT)
      G68-5 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher ECM
      G68-15 (CANL) - G8-16 (BAT)
      G68-6 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 1 CAN junction connector
      G68-16 (CANL) - G8-16 (BAT)
      G68-10 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Air conditioning amplifier assembly*3, *4
      G68-20 (CANL) - G8-16 (BAT)
      *1: w/ Entry and Start System
      *2: for 4WD
      *3: for Automatic Air Conditioning System
      *4: for Manual Air Conditioning System
      Result
      Result Proceed to
      OK A
      NG (No. 1 CAN junction connector CAN main wire) B
      NG (ECU or sensor CAN main or branch wires) C

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    C

    GO TO STEP 6 Click here

    B

  2. CONNECT CONNECTOR


    1. Reconnect the G68 No. 2 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 1 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 1 CAN junction connector.

      B0025W1C11
      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Brake Actuator Assembly (Skid Control ECU) *d to Airbag Sensor Assembly
      *e to Spiral with Sensor Cable Sub-assembly (Steering Angle Sensor) *f to Combination Meter Assembly
      *g to No. 2 CAN Junction Connector *h to Engine Stop and Start ECU (w/ Stop and Start System)
      *i to Headlight Leveling ECU Assembly (for LED Headlight or w/ Headlight Cleaner System) *j to Central Gateway ECU (Network Gateway ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      G67-1 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Brake actuator assembly (skid control ECU)
      G67-11 (CANL) - G8-16 (BAT)
      G67-2 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Airbag sensor assembly
      G67-12 (CANL) - G8-16 (BAT)
      G67-3 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Spiral with sensor cable sub-assembly (steering angle sensor)
      G67-13 (CANL) - G8-16 (BAT)
      G67-5 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Combination meter assembly
      G67-15 (CANL) - G8-16 (BAT)
      G67-6 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 2 CAN junction connector
      G67-16 (CANL) - G8-16 (BAT)
      G67-7 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Engine stop and start ECU*1
      G67-17 (CANL) - G8-16 (BAT)
      G67-8 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Headlight leveling ECU assembly*2
      G67-18 (CANL) - G8-16 (BAT)
      G67-9 (CANH) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Central gateway ECU (network gateway ECU)
      G67-19 (CANL) - G8-16 (BAT)
      *1: w/ Stop and Start System
      *2: for LED Headlight or w/ Headlight Cleaner System
      Result
      Result Proceed to
      OK A
      NG (No. 2 CAN junction connector CAN main wire) B
      NG (Central gateway ECU [network gateway ECU] CAN branch wire) C
      NG (ECU or sensor CAN main or branch wires) D

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

    D

    CHECK FOR SHORT TO B+ IN CAN BUS WIRE (ECU, SENSOR) Click here

    C

  4. CONNECT CONNECTOR


    1. Reconnect the G67 No. 1 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (CENTRAL GATEWAY ECU)


    1. B0025V2C04
      *a

      Front view of wire harness connector

      (to Central Gateway ECU [Network Gateway ECU])
      *b Front view of DLC3

      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
      G128-18 (CA4H) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      G128-17 (CA4L) - G8-16 (BAT)
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (CENTRAL GATEWAY ECU - NO. 1 CAN JUNCTION CONNECTOR)

  6. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (ECU, SENSOR)


    1. B00289FC14
      *a

      Component with harness connected

      (Central Gateway ECU [Network Gateway ECU])
      *b Front view of DLC3

      Reconnect the CAN junction connector.

    2. Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the bus line shorted to +B is connected.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G128-18 (CA4H) - G8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      G128-17 (CA4L) - G8-16 (BAT)

      Tech Tips

      If the resistance changes to 6 kΩ or higher 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 BUS WIRES OR CONNECTOR