CAN COMMUNICATION SYSTEM(for LHD without Central Gateway ECU) Short in CAN Bus Lines

DESCRIPTION

There may be a short circuit between the CAN bus lines when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 53 Ω.

Detection Item Trouble Area
The resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 53 Ω.

  • Short between CAN bus lines

  • ECM

  • Combination meter assembly

  • Power steering ECU assembly

  • Air conditioning amplifier assembly

  • Airbag sensor assembly

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

  • Radio and display receiver 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

  • DLC3 CAN branch wire or connector
*1: w/ Audio and Visual System (for Radio and Display Type)
*2: for 4WD/AWD
*3: w/ Stop and Start System

WIRING DIAGRAM

A01QQDQE01
A01QSVAE01

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 (NO. 6 CAN JUNCTION CONNECTOR)


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

      A01QT4JC32
      *a

      Front view of wire harness connector

      (to No. 6 CAN Junction Connector)

      		 *b to Main Body ECU (Multiplex Network Body ECU)
      *c to Power Steering ECU Assembly *d to Brake Actuator Assembly (Skid Control ECU)
      *e to No. 7 CAN Junction Connector *f to ECM
      *g to DLC3 *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) - G171-11 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      G171-2 (CANH) - G171-12 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
      G171-3 (CANH) - G171-13 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Brake actuator assembly (skid control ECU)
      G171-4 (CANH) - G171-14 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 7 CAN junction connector
      G171-5 (CANH) - G171-15 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
      G171-8 (CANH) - G171-18 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher DLC3
      G171-9 (CANH) - G171-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag sensor assembly
      G171-10 (CANH) - G171-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly
      Result
      Result Proceed to
      OK A
      NG (No. 7 CAN junction connector CAN main wire) B
      NG (ECM CAN main wire) C
      NG (DLC3 CAN branch wires) D
      NG (ECU or sensor CAN branch wires) E

    A

    REPLACE NO. 6 CAN JUNCTION CONNECTOR

    C

    CONNECT CONNECTOR Click here

    D

    REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO DLC3 (CANH, CANL)

    E

    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 IN CAN BUS WIRES (NO. 7 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 7 CAN junction connector.

      A01QT4JC40
      *a

      Front view of wire harness connector

      (to No. 7 CAN Junction Connector)

      		 *b to Combination Meter Assembly
      *c to Radio and Display Receiver Assembly (w/ Audio and Visual System [for Radio and Display Type]) *d to Engine Stop and Start ECU (w/ Stop and Start System)
      *e to 4WD ECU Assembly (for 4WD/AWD) *f to No. 6 CAN Junction Connector
      *g 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) - G172-11 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Combination meter assembly
      G172-3 (CANH) - G172-13 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Radio and display receiver assembly*1
      G172-4 (CANH) - G172-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU*3
      G172-6 (CANH) - G172-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher 4WD ECU assembly*2
      G172-8 (CANH) - G172-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 6 CAN junction connector
      G172-9 (CANH) - G172-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Spiral with sensor cable sub-assembly (steering angle sensor)
      *1: w/ Audio and Visual System (for Radio and Display Type)
      *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 (Combination meter assembly CAN main wire) C
      NG (ECU or sensor CAN 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 IN CAN BUS WIRES (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 IN CAN BUS WIRES (COMBINATION METER ASSEMBLY)


    1. A01QT0OC08
      *a

      Rear view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G16-32 (CANH) - G16-31 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (COMBINATION METER ASSEMBLY - NO. 7 CAN JUNCTION CONNECTOR)

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


    1. A01QQYTC19
      *a 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 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
      G14-6 (CANH) - G14-14 (CANL) 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

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

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

  7. CONNECT CONNECTOR


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

      Result
      Proceed to
      NEXT

    NEXT

  8. CHECK FOR SHORT IN CAN BUS WIRES (ECM)


    1. A01QQS9C02
      *A for 2AR-FE, 3ZR-FAE, 3ZR-FE
      *B for 2WW
      *C for 2AD-FTV, 2AD-FHV, 2AD-CCo, 2AD-DPF
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Resistance
      for 2AR-FE, 3ZR-FAE, 3ZR-FE
      Tester Connection Condition Specified Condition
      A62-13 (CANH) - A62-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      for 2WW
      Tester Connection Condition Specified Condition
      A62-26 (CANH) - A62-25 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      for 2AD-FTV, 2AD-FHV, 2AD-CCo, 2AD-DPF
      Tester Connection Condition Specified Condition
      A61-7 (CANH) - A61-6 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM for 2AR-FE: Click here
    REPLACE ECM for 3ZR-FAE: Click here
    REPLACE ECM for 3ZR-FE: Click here
    REPLACE ECM for 2AD-FTV: Click here
    REPLACE ECM for 2AD-FHV: Click here
    REPLACE ECM for 2AD-CCo, 2AD-DPF: Click here
    REPLACE ECM for 2WW: Click here

    NG

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