CAN COMMUNICATION SYSTEM(for LHD) 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 central gateway ECU is below 54 Ω.

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

  • Short in bus 2 CAN main wires

  • Short 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 IN CAN BUS WIRES (ECM - NO. 1 CAN JUNCTION CONNECTOR)


    1. B002B6UE01
      Text in Illustration
      *A for 2GR-FXE
      *B for 2AR-FSE
      *a

      Front view of wire harness connector

      (to ECM)

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

    2. Disconnect the ECM connector.

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

      Standard Resistance
      for 2GR-FXE
      Tester Connection Condition Specified Condition
      A20-13 (CANH) - A20-26 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      for 2AR-FSE
      Tester Connection Condition Specified Condition
      A79-13 (CANH) - A79-26 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      Result
      Result Proceed to
      OK (for 2GR-FXS) A
      OK (for 2AR-FSE) B
      NG C

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

  2. CONNECT CONNECTOR


    1. Reconnect the A20*1 or A79*2 ECM connector.


      • *1: for 2GR-FXE

      • *2: for 2AR-FSE


    NEXT

  3. CHECK FOR SHORT IN CAN BUS WIRES (POWER MANAGEMENT CONTROL ECU - NO. 3 CAN JUNCTION CONNECTOR)


    1. B002BT1E01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N92-25 (CA1H) - N92-24 (CA1L) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    NG

  4. CONNECT CONNECTOR


    1. Reconnect the N92 power management control ECU connector.


    NEXT

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


    1. B002B67E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Central Gateway ECU)

      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) - N176-17 (CA4L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

    OK

    REPLACE CENTRAL GATEWAY ECU Click here

    NG

  6. CONNECT CONNECTOR


    1. Reconnect the N176 central 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.

      B002BUVE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b to No. 2 CAN Junction Connector
      *c to ECM *d to Parking Brake ECU Assembly

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      U67-5 (CANH) - U67-16 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 2 CAN junction connector
      U67-6 (CANH) - U67-17 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω ECM
      U67-7 (CANH) - U67-18 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Parking brake ECU assembly
      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 U67 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.

      B002BPGE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b to No. 3 CAN Junction Connector
      *c to Steering Angle Sensor *d to Yaw Rate Sensor
      *e to Combination Meter Assembly *f to Airbag Sensor Assembly
      *g to No. 1 CAN Junction Connector *h to Main Body ECU (Multiplex Network Body ECU)
      *i 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) - N178-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 3 CAN junction connector
      N178-2 (CANH) - N178-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Steering angle sensor
      N178-3 (CANH) - N178-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Yaw rate sensor
      N178-4 (CANH) - N178-15 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Combination meter assembly
      N178-5 (CANH) - N178-16 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Airbag sensor assembly
      N178-6 (CANH) - N178-17 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 1 CAN junction connector
      N178-7 (CANH) - N178-18 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      N178-9 (CANH) - N178-20 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Skid control ECU assembly
      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 N178 No. 2 CAN junction connector.


    NEXT

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


    1. Disconnect the No. 3 CAN junction connector.

      B002BPQE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 3 CAN Junction Connector)

      		 *b to Power Steering ECU Assembly
      *c to Air Conditioning Amplifier Assembly *d to Central Gateway ECU
      *e to Certification ECU (Smart Key ECU Assembly) *f to Power Management Control ECU
      *g to Front Steering Control ECU (w/ Variable Gear Ratio Steering System) *h to No. 2 CAN Junction Connector
      *i 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) - N177-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power steering ECU assembly
      N177-2 (CANH) - N177-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Air conditioning amplifier assembly
      N177-3 (CANH) - N177-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU
      N177-4 (CANH) - N177-15 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      N177-5 (CANH) - N177-16 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Power management control ECU
      N177-7 (CANH) - N177-18 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Front steering control ECU*1
      N177-8 (CANH) - N177-19 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 2 CAN junction connector
      N177-9 (CANH) - N177-20 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Combination meter mirror ECU*2

      • *1: w/ Variable Gear Ratio Steering System

      • *2: w/ Headup Display System

      Result
      Result Proceed to
      OK A
      NG (Power management control ECU CAN main wire) B
      NG (Central 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 - POWER MANAGEMENT CONTROL ECU)

    C

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - CENTRAL 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. B002BHJE02
      Text in Illustration
      *a

      Component with harness connected

      (Central 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
      N176-18 (CA4H) - N176-17 (CA4L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

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