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

DESCRIPTION

There may be a short circuit between one of the CAN bus wires and GND when no resistance exists between terminal 18 (CA4H) of the central gateway ECU and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU and terminal 4 (CG) of the DLC3.

Detection Item Trouble Area
No resistance exists between terminal 18 (CA4H) of the central gateway ECU and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU and terminal 4 (CG) of the DLC3.

  • Short to GND in bus 2 CAN main wires

  • Short to GND in bus 2 CAN branch wires

  • ECM

  • Combination meter assembly

  • Central gateway ECU

  • Power steering ECU assembly

  • Air conditioning amplifier assembly

  • Airbag sensor assembly

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

  • Certification ECU (smart key ECU assembly)*1

  • 4WD ECU assembly*2

  • Brake actuator assembly (skid control ECU)

  • Main body ECU (multiplex network body ECU)

  • Engine stop and start ECU*3

  • No. 6 CAN junction connector

  • No. 7 CAN junction connector
*1: w/ Entry and Start System
*2: for 4WD/AWD
*3: w/ Stop and Start System

WIRING DIAGRAM

A01V9RFE06
A01V771E02

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 GND IN CAN BUS WIRE (NO. 6 CAN JUNCTION CONNECTOR)


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

      A01VAJYC28
      *a

      Front view of wire harness connector

      (to No. 6 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Main Body ECU (Multiplex Network Body ECU) *d to Power Steering ECU Assembly
      *e to Brake Actuator Assembly (Skid Control ECU) *f to No. 7 CAN Junction Connector
      *g to ECM *h to Airbag Sensor Assembly
      *i to Air Conditioning Amplifier Assembly - -

    2. Disconnect the No. 6 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
      G171-1 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      G171-11 (CANL) - G14-4 (CG)
      G171-2 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
      G171-12 (CANL) - G14-4 (CG)
      G171-3 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Brake actuator assembly (skid control ECU)
      G171-13 (CANL) - G14-4 (CG)
      G171-4 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 7 CAN junction connector
      G171-14 (CANL) - G14-4 (CG)
      G171-5 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher ECM
      G171-15 (CANL) - G14-4 (CG)
      G171-9 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag sensor assembly
      G171-19 (CANL) - G14-4 (CG)
      G171-10 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly
      G171-20 (CANL) - G14-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (No. 7 CAN junction connector CAN main wire) B
      NG (ECU or sensor CAN main or branch wires) C

    A

    REPLACE NO. 6 CAN JUNCTION CONNECTOR

    C

    GO TO STEP 6 Click here

    B

  2. CONNECT CONNECTOR


    1. Reconnect the G171 No. 6 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 7 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 7 CAN junction connector.

      A01VAJYC29
      *a

      Front view of wire harness connector

      (to No. 7 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Combination Meter Assembly *d to Engine Stop and Start ECU (w/ Stop and Start System)
      *e to Certification ECU (Smart Key ECU Assembly) (w/ Entry and Start System) *f to 4WD ECU Assembly (for 4WD/AWD)
      *g to Central Gateway ECU *h to No. 6 CAN Junction Connector
      *i to Spiral with Sensor Cable Sub-assembly (Steering Angle Sensor) - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      G172-1 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Combination meter assembly
      G172-11 (CANL) - G14-4 (CG)
      G172-4 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU*3
      G172-14 (CANL) - G14-4 (CG)
      G172-5 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)*1
      G172-15 (CANL) - G14-4 (CG)
      G172-6 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher 4WD ECU assembly*2
      G172-16 (CANL) - G14-4 (CG)
      G172-7 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU
      G172-17 (CANL) - G14-4 (CG)
      G172-8 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 6 CAN junction connector
      G172-18 (CANL) - G14-4 (CG)
      G172-9 (CANH) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Spiral with sensor cable sub-assembly (steering angle sensor)
      G172-19 (CANL) - G14-4 (CG)
      *1: w/ Entry and Start System
      *2: for 4WD/AWD
      *3: w/ Stop and Start System
      Result
      Result Proceed to
      OK A
      NG (No. 6 CAN junction connector CAN main wire) B
      NG (Central gateway ECU CAN branch wire) C
      NG (ECU or sensor CAN main or branch wires) D

    A

    REPLACE NO. 7 CAN JUNCTION CONNECTOR

    B

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

    D

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

    C

  4. CONNECT CONNECTOR


    1. Reconnect the G172 No. 7 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

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


    1. A01V8E2C23
      *a

      Front view of wire harness connector

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

      Disconnect the central gateway ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G170-18 (CA4H) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      G170-17 (CA4L) - G14-4 (CG)
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU Click here

    NG

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

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


    1. A01V9L9C33
      *a

      Component with harness connected

      (Central 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 GND is connected.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G170-18 (CA4H) - G14-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      G170-17 (CA4L) - G14-4 (CG)

      Tech Tips

      If the resistance changes to 200 Ω 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