CAN COMMUNICATION SYSTEM Check Bus 2 Line for Short to +B

DESCRIPTION

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

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

  • 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 TO B+ IN CAN BUS WIRE (NO. 1 CAN JUNCTION CONNECTOR)


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

      A002PXUE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Main Body ECU (Instrument Panel Junction Block Assembly) *d to Brake Actuator Assembly (Skid Control ECU)
      *e to No. 2 CAN Junction Connector *f to ECM

    2. Disconnect the No. 1 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
      A50-7 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Main body ECU (instrument panel junction block assembly)
      A50-18 (CANL) - H16-16 (BAT)
      A50-8 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Brake actuator assembly (skid control ECU)
      A50-19 (CANL) - H16-16 (BAT)
      A50-9 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 2 CAN junction connector
      A50-20 (CANL) - H16-16 (BAT)
      A50-10 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher ECM
      A50-21 (CANL) - H16-16 (BAT)
      Result
      Result Proceed to
      OK A
      NG (No. 2 CAN junction connector CAN main wire) B
      NG (ECU or sensor CAN wires) C

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    C

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

    B

  2. CONNECT CONNECTOR


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


    NEXT

  3. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 2 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 2 CAN junction connector.

      A002OBVE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Pre-collision City Sensor (w/ Pre-collision System) *d to No. 3 CAN Junction Connector
      *e 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) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Pre-collision city sensor*
      Q13-7 (CANL) - H16-16 (BAT)
      Q13-2 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 3 CAN junction connector
      Q13-8 (CANL) - H16-16 (BAT)
      Q13-3 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 1 CAN junction connector
      Q13-9 (CANL) - H16-16 (BAT)

      • *: 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 TO B+ IN CAN BUS WIRE (ECU, SENSOR) Click here

    C

  4. CONNECT CONNECTOR


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


    NEXT

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


    1. w/ Entry and Start System:


      1. Disconnect the No. 3 CAN junction connector.

        A002LYFE02
        Text in Illustration
        *a

        Rear view of wire harness connector

        (to No. 3 CAN Junction Connector)

        		 *b Front view of DLC3
        *c to Power Management Control ECU *d to Certification ECU (Smart Key ECU Assembly)
        *e to Power Steering ECU Assembly *f to No. 2 CAN Junction Connector
        *g to Spiral with Sensor Cable Sub-assembly (Steering Angle Sensor) *h to Yaw Rate Sensor
        *i to Network Gateway ECU *j

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

        • to Air Conditioning Amplifier Assembly (for 1ZR-FAE, 2ZR-FAE)
        *k to Combination Meter Assembly *l 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) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Power management control ECU
        H88-12 (CANL) - H16-16 (BAT)
        H88-2 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Certification ECU (smart key ECU assembly)
        H88-13 (CANL) - H16-16 (BAT)
        H88-3 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Power steering ECU assembly
        H88-14 (CANL) - H16-16 (BAT)
        H88-4 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 2 CAN junction connector
        H88-15 (CANL) - H16-16 (BAT)
        H88-5 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Spiral with sensor cable sub-assembly (steering angle sensor)
        H88-16 (CANL) - H16-16 (BAT)
        H88-6 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Yaw rate sensor
        H88-17 (CANL) - H16-16 (BAT)
        H88-7 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Network gateway ECU
        H88-18 (CANL) - H16-16 (BAT)
        H88-8 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher

        • Engine stop and start ECU*1

        • Air conditioning amplifier assembly*2
        H88-19 (CANL) - H16-16 (BAT)
        H88-9 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Combination meter assembly
        H88-20 (CANL) - H16-16 (BAT)
        H88-11 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Airbag sensor assembly
        H88-22 (CANL) - H16-16 (BAT)

        • *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.

        A002MN4E02
        Text in Illustration
        *a

        Rear view of wire harness connector

        (to No. 3 CAN Junction Connector)

        		 *b Front view of DLC3
        *c to Air Conditioning Amplifier 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) *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
        H88-2 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Air conditioning amplifier assembly
        H88-13 (CANL) - H16-16 (BAT)
        H88-3 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Power steering ECU assembly
        H88-14 (CANL) - H16-16 (BAT)
        H88-4 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 2 CAN junction connector
        H88-15 (CANL) - H16-16 (BAT)
        H88-5 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Spiral with sensor cable sub-assembly (steering angle sensor)
        H88-16 (CANL) - H16-16 (BAT)
        H88-6 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Yaw rate sensor
        H88-17 (CANL) - H16-16 (BAT)
        H88-7 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Network gateway ECU
        H88-18 (CANL) - H16-16 (BAT)
        H88-8 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Engine stop and start ECU*
        H88-19 (CANL) - H16-16 (BAT)
        H88-9 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Combination meter assembly
        H88-20 (CANL) - H16-16 (BAT)
        H88-11 (CANH) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Airbag sensor assembly
        H88-22 (CANL) - H16-16 (BAT)

        • *: w/ Stop and Start System

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

    A

    REPLACE NO. 3 CAN JUNCTION CONNECTOR

    B

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

    D

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

    C

  6. CONNECT CONNECTOR


    1. Reconnect the H88 No. 3 CAN junction connector.


    NEXT

  7. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NETWORK GATEWAY ECU - NO. 3 CAN JUNCTION CONNECTOR)


    1. A002MB7E01
      Text in Illustration
      *a

      Front view of wire harness connector

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

      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) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      H131- 17 (CA4L) - H16-16 (BAT)
      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

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

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


    1. A002NP1E02
      Text in Illustration
      *a

      Component with harness connected

      (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
      H131-18 (CA4H) - H16-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      H131-17 (CA4L) - H16-16 (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.


    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR CAN WIRES OR CONNECTOR