CAN COMMUNICATION SYSTEM Check Bus 2 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the bus 2 CAN main wires and/or CAN branch wires when the resistance between terminals 18 (CA4H) and 17 (CA4L) of the network gateway ECU is below 54 Ω.

Detection Item Trouble Area
Resistance between terminals 18 (CA4H) and 17 (CA4L) of network gateway ECU is below 54 Ω.

  • Short in bus 2 CAN main wires

  • Short in bus 2 CAN branch wires

  • Network gateway ECU

  • ECM

  • Brake actuator assembly (skid control ECU)

  • Main body ECU (instrument panel junction block assembly)

  • Pre-collision city sensor*1

  • Certification ECU (smart key ECU assembly)*2

  • Power management control ECU*2

  • Power steering ECU assembly

  • Yaw rate sensor

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

  • Airbag sensor assembly

  • Engine stop and start ECU*3

  • Air conditioning amplifier assembly*4, *5

  • Combination meter assembly

  • No. 1 CAN junction connector

  • No. 2 CAN junction connector

  • No. 3 CAN junction connector

WIRING DIAGRAM

A002QXME03
A002NEOE02
A002Q3VE02
A002QXME04
A002Q3CE02
A002PVME02

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 (ECM - NO. 1 CAN JUNCTION CONNECTOR)


    1. A002O74E02
      Text in Illustration
      *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
      for 1ZR-FAE, 2ZR-FAE
      Tester Connection Condition Specified Condition
      A76-13 (CANH) - A76-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      for 1WW
      Tester Connection Condition Specified Condition
      A76-26 (CANH) - A76-25 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result Proceed to
      OK (for 1ZR-FAE) A
      OK (for 2ZR-FAE) B
      OK (for 1WW) C
      NG D

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    D

  2. CONNECT CONNECTOR


    1. Reconnect the A76 ECM connector.


    NEXT

  3. CHECK FOR SHORT IN CAN BUS WIRES (COMBINATION METER ASSEMBLY - NO. 3 CAN JUNCTION CONNECTOR)


    1. A002OP1E02
      Text in Illustration
      *a

      Front 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
      H62-22 (CANH) - H62-23 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

  4. CONNECT CONNECTOR


    1. Reconnect the H62 combination meter assembly connector.


    NEXT

  5. CHECK FOR SHORT IN CAN BUS WIRES (NETWORK GATEWAY ECU - NO. 3 CAN JUNCTION CONNECTOR)


    1. A002MJ5E02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Network Gateway ECU)

      Disconnect the network gateway ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H131-18 (CA4H) - H131- 17 (CA4L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    A

    REPLACE NETWORK GATEWAY ECU Click here

    B

    REPLACE NETWORK GATEWAY ECU Click here

    C

  6. CONNECT CONNECTOR


    1. Reconnect the H131 network gateway ECU connector.


    NEXT

  7. CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 1 CAN junction connector.

      A002Q96E02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b to Main Body ECU (Instrument Panel Junction Block Assembly)
      *c to Brake Actuator Assembly (Skid Control ECU) *d to No. 2 CAN Junction Connector
      *e to ECM - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      A50-7 (CANH) - A50-18 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (instrument panel junction block assembly)
      A50-8 (CANH) - A50-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Brake actuator assembly (skid control ECU)
      A50-9 (CANH) - A50-20 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 2 CAN junction connector
      A50-10 (CANH) - A50-21 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
      Result
      Result Proceed to
      OK A
      NG (ECM CAN main wire) B
      NG (No. 2 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    B

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

    D

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

    C

  8. CONNECT CONNECTOR


    1. Reconnect the A50 No. 1 CAN junction connector.


    NEXT

  9. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 2 CAN junction connector.

      A002MOKE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b to Pre-collision City Sensor (w/ Pre-collision System)
      *c to No. 3 CAN Junction Connector *d to No. 1 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
      Q13-1 (CANH) - Q13-7 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Pre-collision city sensor*
      Q13-2 (CANH) - Q13-8 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 3 CAN junction connector
      Q13-3 (CANH) - Q13-9 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 1 CAN junction connector

      • *: w/ Pre-collision System

      Result
      Result Proceed to
      OK A
      NG (No. 1 CAN junction connector CAN main wire) B
      NG (No. 3 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    B

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

    D

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

    C

  10. CONNECT CONNECTOR


    1. Reconnect the Q13 No. 2 CAN junction connector.


    NEXT

  11. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 CAN JUNCTION CONNECTOR)


    1. w/ Entry and Start System:


      1. Disconnect the No. 3 CAN junction connector.

        A002LUZE02
        Text in Illustration
        *a

        Rear view of wire harness connector

        (to No. 3 CAN Junction Connector)

        		 *b to Power Management Control ECU
        *c to Certification ECU (Smart Key ECU Assembly) *d to Power Steering ECU Assembly
        *e to No. 2 CAN Junction Connector *f to Spiral with Sensor Cable Sub-assembly (Steering Angle Sensor)
        *g to Yaw Rate Sensor *h to Network Gateway ECU
        *i

        • to Engine Stop and Start ECU (w/ Stop and Start System)

        • to Air Conditioning Amplifier Assembly (for 1ZR-FAE, 2ZR-FAE)

        		 *j to Combination Meter Assembly
        *k to Airbag Sensor Assembly - -

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

        Standard Resistance
        Tester Connection Condition Specified Condition Connect to
        H88-1 (CANH) - H88-12 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power management control ECU
        H88-2 (CANH) - H88-13 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
        H88-3 (CANH) - H88-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
        H88-4 (CANH) - H88-15 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 2 CAN junction connector
        H88-5 (CANH) - H88-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Spiral with sensor cable sub-assembly (steering angle sensor)
        H88-6 (CANH) - H88-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Yaw rate sensor
        H88-7 (CANH) - H88-18 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Network gateway ECU
        H88-8 (CANH) - H88-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher

        • Engine stop and start ECU*1

        • Air conditioning amplifier assembly*2
        H88-9 (CANH) - H88-20 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Combination meter assembly
        H88-11 (CANH) - H88-22 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag sensor assembly

        • *1: w/ Stop and Start System

        • *2: for 1ZR-FAE, 2ZR-FAE

    2. w/o Entry and Start System:


      1. Disconnect the No. 3 CAN junction connector.

        A002MVIE02
        Text in Illustration
        *a

        Rear view of wire harness connector

        (to No. 3 CAN Junction Connector)

        		 *b to Air Conditioning Amplifier Assembly
        *c to Power Steering ECU Assembly *d to No. 2 CAN Junction Connector
        *e to Spiral with Sensor Cable Sub-assembly (Steering Angle Sensor) *f to Yaw Rate Sensor
        *g to Network Gateway ECU *h to Engine Stop and Start ECU (w/ Stop and Start System)
        *i to Combination Meter Assembly *j to Airbag Sensor Assembly

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

        Standard Resistance
        Tester Connection Condition Specified Condition Connect to
        H88-2 (CANH) - H88-13 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly
        H88-3 (CANH) - H88-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
        H88-4 (CANH) - H88-15 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 2 CAN junction connector
        H88-5 (CANH) - H88-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Spiral with sensor cable sub-assembly (steering angle sensor)
        H88-6 (CANH) - H88-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Yaw rate sensor
        H88-7 (CANH) - H88-18 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Network gateway ECU
        H88-8 (CANH) - H88-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU*
        H88-9 (CANH) - H88-20 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Combination meter assembly
        H88-11 (CANH) - H88-22 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag sensor assembly

        • *: w/ Stop and Start System

        Result
        Result Proceed to
        OK A
        NG (Combination meter assembly CAN main wire) B
        NG (Network gateway ECU CAN branch wire) C
        NG (No. 2 CAN junction connector CAN main wire) D
        NG (ECU or sensor CAN branch wires) E

    A

    REPLACE NO. 3 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

    C

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - NETWORK GATEWAY ECU)

    D

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

    E

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


    1. A002OUEE02
      Text in Illustration
      *a

      Component with harness connected

      (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
      H131-18 (CA4H) - H131-17 (CA4L) 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