CAN COMMUNICATION SYSTEM(for RHD) Check CAN Bus Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the V bus main lines and/or CAN branch lines when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ω.

Symptom Trouble Area
Resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ω.

  • Short in CAN main bus line

  • Short in CAN branch line

  • Combination meter assembly

  • Power steering ECU assembly

  • Main body ECU (multiplex network body ECU)

  • Steering sensor

  • Airbag ECU assembly

  • ECM

  • Skid control ECU (brake actuator assembly)

  • Air conditioning amplifier assembly

  • Certification ECU (smart key ECU assembly)

  • Clearance warning ECU assembly

  • Option connector (bus buffer ECU)

  • Navigation receiver assembly

    (for Navigation Receiver Type)

  • Parking brake ECU assembly

  • Engine stop and start ECU

    (w/ Stop and Start System)

  • No. 3 CAN junction connector

  • No. 4 CAN junction connector

WIRING DIAGRAM

A01UCL8E01
A01UF70E01
A01UDS3E01

CAUTION / NOTICE / HINT

Note


  • Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any 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 engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

    Click here

  • 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

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the engine switch on (IG), wait at least 61 seconds, and then drive the vehicle at a speed of 20 km/h (12 mph) or more for 10 minutes or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed.

    Click here

  • Before replacing the main body ECU (multiplex network body ECU), ECM or certification ECU (smart key ECU assembly), refer to Service Bulletin.

Tech Tips


  • Operating the engine switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • 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 LINES (COMBINATION METER ASSEMBLY - NO. 4 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the G16 combination meter assembly connector.

    3. A01UCNMC49
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G16-23 (CANH) - G16-22 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

  2. CHECK FOR SHORT IN CAN BUS LINES (ECM - NO. 3 CAN JUNCTION CONNECTOR)


    1. Reconnect the G16 combination meter assembly connector.

    2. Disconnect the A53 ECM connector.

    3. B006MO7C36
      *a

      Front view of wire harness connector

      (to ECM)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A53-13 (CANH) - A53-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result Proceed to
      OK (2GR-FE) A
      OK (2AR-FE) B
      NG C

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

  3. CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR)


    1. Reconnect the A53 ECM connector.

    2. Disconnect the G98 No. 4 CAN junction connector.

      A01UE4NC76
      *a

      Front view of wire harness connector

      (to No. 4 CAN Junction Connector)

      		 *b to No. 3 CAN Junction Connector
      *c to Combination Meter Assembly *d to Certification ECU (Smart Key ECU Assembly)
      *e to Power Steering ECU Assembly *f to DLC3
      *g to Steering Sensor *h to Clearance Warning ECU Assembly
      *i to Option Connector (Bus Buffer ECU) - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      G98-1 (CANH) - G98-11 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 3 CAN junction connector
      G98-2 (CANH) - G98-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Combination meter assembly
      G98-3 (CANH) - G98-13 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      G98-5 (CANH) - G98-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
      G98-6 (CANH) - G98-16 (CANL) Cable disconnected from negative (-) battery terminal 1 MΩ or higher DLC3
      G98-7 (CANH) - G98-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Steering sensor
      G98-9 (CANH) - G98-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Clearance warning ECU assembly
      G98-10 (CANH) - G98-20 (CANL) Cable disconnected from negative (-) battery terminal

      200 Ω or higher*1

      1 MΩ or higher*2

      		 Option connector (bus buffer ECU)
      *1: When a dealer-installed option is connected
      *2: When a dealer-installed option is not connected
      Result
      Result Proceed to
      OK A
      NG (No. 3 CAN junction connector main bus line) B
      NG (ECU or sensor branch line) C
      NG (DLC3 branch line) D
      NG (Combination meter assembly main bus line) E

    A

    REPLACE NO. 4 CAN JUNCTION CONNECTOR

    C

    GO TO STEP 5 Click here

    D

    REPAIR OR REPLACE CAN BRANCH LINES CONNECTED TO DLC3

    E

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (COMBINATION METER ASSEMBLY - NO. 4 CAN JUNCTION CONNECTOR)

    B

  4. CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR)


    1. Disconnect the G97 No. 3 CAN junction connector.

      A01UE4NC65
      *a

      Front view of wire harness connector

      (to No. 3 CAN Junction Connector)

      		 *b

      to Engine Stop and Start ECU

      (w/ Stop and Start System)
      *c to ECM *d to Main Body ECU (Multiplex Network Body ECU)
      *e to Airbag ECU Assembly *f to Parking Brake ECU Assembly
      *g to Skid Control ECU (Brake Actuator Assembly) *h to No. 4 CAN Junction Connector
      *i

      to Navigation Receiver Assembly

      (for Navigation Receiver Type)

      		 *j to Air Conditioning Amplifier Assembly

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      G97-1 (CANH) - G97-11 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU*1
      G97-3 (CANH) - G97-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
      G97-4 (CANH) - G97-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      G97-5 (CANH) - G97-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag ECU assembly
      G97-6 (CANH) - G97-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Parking brake ECU assembly
      G97-7 (CANH) - G97-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Skid control ECU (brake actuator assembly)
      G97-8 (CANH) - G97-18 (CANL) Cable disconnected from negative (-) battery terminal 1 MΩ or higher No. 4 CAN junction connector
      G97-9 (CANH) - G97-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Navigation receiver assembly*2
      G97-10 (CANH) - G97-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly

      *1: w/ Stop and Start System

      *2: for Navigation Receiver Type

      Result
      Result Proceed to
      OK A
      NG (No. 4 CAN junction connector main bus line) B
      NG (ECU or sensor branch line) C
      NG (ECM main bus line) D

    A

    REPLACE NO. 3 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 3 CAN JUNCTION CONNECTOR)

    D

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (ECM - NO. 3 CAN JUNCTION CONNECTOR)

    C

  5. CHECK FOR SHORT IN CAN BUS LINES (ECU, SENSOR)


    1. Reconnect all wire harness connectors.

    2. Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited branch line is connected.

      Click here

    3. A01UDFPC98
      *1 DLC3

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G9-6 (CANH) - G9-14 (CANL) 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.

      Result
      Result
      OK
      NG

    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINES OR CONNECTOR