CAN COMMUNICATION SYSTEM(for LHD) Check Bus 4 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the bus 4 CAN main wires and/or CAN branch wires when the resistance between terminals 22 (CA2H) and 7 (CA2L) of the central gateway ECU is below 54 Ω.

Detection Item Trouble Area
Resistance between terminals 22 (CA2H) and 7 (CA2L) of central gateway ECU is below 54 Ω.

  • Short in bus 4 CAN main wires

  • Short in bus 4 CAN branch wires

  • Skid control ECU assembly

  • Absorber control ECU*1

  • Power steering ECU assembly

  • Front steering control ECU*2

  • Driving support ECU assembly*3

  • Rear steering control ECU*4

  • Central gateway ECU

  • No. 5 CAN junction connector

  • No. 6 CAN junction connector

  • No. 7 CAN junction connector

  • No. 1 CAN junction terminal

WIRING DIAGRAM

B002BO2E02
B002BLIE02

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 (SKID CONTROL ECU ASSEMBLY - NO. 5 CAN JUNCTION CONNECTOR)


    1. B002BN1E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU Assembly)

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

    2. Disconnect the skid control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A14-7 (CA2H) - A14-6 (CA2L) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE SKID CONTROL ECU ASSEMBLY Click here

    NG

  2. CONNECT CONNECTOR


    1. Reconnect the A14 skid control ECU assembly connector.


    NEXT

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


    1. B002BBZE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 1 CAN Junction Terminal)

      Disconnect the No. 1 CAN junction terminal connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      U56-3 (CANH) - U56-2 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE NO. 1 CAN JUNCTION TERMINAL

    NG

  4. CONNECT CONNECTOR


    1. Reconnect the U56 No. 1 CAN junction terminal connector.


    NEXT

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


    1. B002C0HE01
      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
      N176-22 (CA2H) - N176- 7 (CA2L) 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. 5 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 5 CAN junction connector.

      B002BN7E01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 5 CAN Junction Connector)

      		 *b to Skid Control ECU Assembly
      *c to Front Steering Control ECU (w/ Variable Gear Ratio Steering System) *d to Absorber Control ECU (w/ Adaptive Variable Suspension System)
      *e to Central Gateway ECU *f to No. 6 CAN Junction Connector
      *g to Power Steering ECU Assembly - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      N133-1 (CANH) - N133-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Skid control ECU assembly
      N133-2 (CANH) - N133-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Front steering control ECU*1
      N133-3 (CANH) - N133-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Absorber control ECU*2
      N133-4 (CANH) - N133-15 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU
      N133-5 (CANH) - N133-16 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 6 CAN junction connector
      N133-6 (CANH) - N133-17 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power steering ECU assembly
      Result
      Result Proceed to
      OK A
      NG (Skid control ECU assembly CAN main wire) B
      NG (Central gateway ECU CAN branch wire) C
      NG (No. 6 CAN junction connector CAN main wire) D
      NG (ECU or sensor CAN branch wires) E

    A

    REPLACE NO. 5 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - SKID CONTROL ECU ASSEMBLY)

    C

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU)

    E

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

    D

  8. CONNECT CONNECTOR


    1. Reconnect the N133 No. 5 CAN junction connector.


    NEXT

  9. CHECK FOR SHORT IN CAN BUS WIRES (NO. 6 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 6 CAN junction connector.

      B002BQQE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 6 CAN Junction Connector)

      		 *b to Driving Support ECU Assembly (w/ Pre-crash Safety System)
      *c to No. 7 CAN Junction Connector *d to No. 5 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
      N165-7 (CANH) - N165-18 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Driving support ECU assembly*
      N165-8 (CANH) - N165-19 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 7 CAN junction connector
      N165-11 (CANH) - N165-22 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 5 CAN junction connector

      • *: w/ Pre-crash Safety System

      Result
      Result Proceed to
      OK A
      NG (No. 5 CAN junction connector CAN main wire) B
      NG (No. 7 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 6 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 6 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR)

    D

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

    C

  10. CONNECT CONNECTOR


    1. Reconnect the N165 No. 6 CAN junction connector.


    NEXT

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


    1. Disconnect the No. 7 CAN junction connector.

      B002BDSE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 7 CAN Junction Connector)

      		 *b to No. 1 CAN Junction Terminal
      *c to No. 6 CAN Junction Connector *d to Rear Steering Control ECU (w/ Dynamic Rear Steering System)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      U54-5 (CANH) - U54-16 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 1 CAN junction terminal
      U54-6 (CANH) - U54-17 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 6 CAN junction connector
      U54-7 (CANH) - U54-18 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Rear steering control ECU*

      • *: w/ Dynamic Rear Steering System

      Result
      Result Proceed to
      OK A
      NG (No. 1 CAN junction terminal CAN main wire) B
      NG (No. 6 CAN junction connector 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. 1 CAN JUNCTION TERMINAL)

    C

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 6 CAN JUNCTION CONNECTOR)

    D

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


    1. B002BLOE01
      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
      N176-22 (CA2H) - N176-7 (CA2L) 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