CAN COMMUNICATION SYSTEM(for LHD) 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 central gateway ECU and terminal 16 (BAT) of the DLC3, or terminal 17 (CA4L) of the central 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 and terminal 16 (BAT) of the DLC3, or terminal 17 (CA4L) of the central 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

  • Central gateway ECU

  • ECM

  • Parking brake ECU assembly

  • Main body ECU (multiplex network body ECU)

  • Skid control ECU assembly

  • Steering angle sensor

  • Airbag sensor assembly

  • Yaw rate sensor

  • Certification ECU (smart key ECU assembly)

  • Air conditioning amplifier assembly

  • Power steering ECU assembly

  • Front steering control ECU*1

  • Combination meter mirror ECU*2

  • Combination meter assembly

  • Power management control ECU

  • No. 1 CAN junction connector

  • No. 2 CAN junction connector

  • No. 3 CAN junction connector

WIRING DIAGRAM

B002C3TE01
B002BGUE02
B002BBDE01

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 power 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 (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the auxiliary 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 power 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 (-) auxiliary battery terminal.

      B002BTPE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to No. 2 CAN Junction Connector *d to ECM
      *e to Parking Brake ECU Assembly - -

    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
      U67-5 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher No. 2 CAN junction connector
      U67-16 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      U67-6 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher ECM
      U67-17 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      U67-7 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Parking brake ECU assembly
      U67-18 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      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 U67 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.

      B002C0SE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to No. 3 CAN Junction Connector *d to Steering Angle Sensor
      *e to Yaw Rate Sensor *f to Combination Meter Assembly
      *g to Airbag Sensor Assembly *h to No. 1 CAN Junction Connector
      *i to Main Body ECU (Multiplex Network Body ECU) *j to Skid Control ECU Assembly

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      N178-1 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher No. 3 CAN junction connector
      N178-12 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N178-2 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Steering angle sensor
      N178-13 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N178-3 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Yaw rate sensor
      N178-14 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N178-4 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Combination meter assembly
      N178-15 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N178-5 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Airbag sensor assembly
      N178-16 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N178-6 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher No. 1 CAN junction connector
      N178-17 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N178-7 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Main body ECU (multiplex network body ECU)
      N178-18 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N178-9 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Skid control ECU assembly
      N178-20 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      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 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 N178 No. 2 CAN junction connector.


    NEXT

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


    1. Disconnect the No. 3 CAN junction connector.

      B002BNJE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 3 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Power Steering ECU Assembly *d to Air Conditioning Amplifier Assembly
      *e to Central Gateway ECU *f to Certification ECU (Smart Key ECU Assembly)
      *g to Power Management Control ECU *h to Front Steering Control ECU (w/ Variable Gear Ratio Steering System)
      *i to No. 2 CAN Junction Connector *j to Combination Meter Mirror ECU (w/ Headup Display System)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      N177-1 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Power steering ECU assembly
      N177-12 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N177-2 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Air conditioning amplifier assembly
      N177-13 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N177-3 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Central gateway ECU
      N177-14 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N177-4 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Certification ECU (smart key ECU assembly)
      N177-15 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N177-5 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Power management control ECU
      N177-16 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N177-7 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Front steering control ECU*1
      N177-18 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N177-8 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher No. 2 CAN junction connector
      N177-19 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N177-9 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Combination meter mirror ECU*2
      N177-20 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      • *1: w/ Variable Gear Ratio Steering System

      • *2: w/ Headup Display System

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

    A

    REPLACE NO. 3 CAN JUNCTION CONNECTOR

    C

    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

    B

  6. CONNECT CONNECTOR


    1. Reconnect the N177 No. 3 CAN junction connector.


    NEXT

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


    1. B002BXWE01
      Text in Illustration
      *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
      N176-18 (CA4H) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N176-17 (CA4L) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

    OK

    REPLACE CENTRAL GATEWAY ECU Click here

    NG

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

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


    1. B002BMBE01
      Text in Illustration
      *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 +B is connected.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N176-18 (CA4H) - N20- 16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N176-17 (CA4L) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      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