CAN COMMUNICATION SYSTEM Check CAN Bus Line for Short to +B (RHD Models)

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and +B when no resistance exists between terminals 6 (CANH) and 16 (BAT) or 14 (CANL) and 16 (BAT) of the DLC3.

Symptom Trouble Area
No resistance exists between terminals 6 (CANH) and 16 (BAT) or 14 (CANL) and 16 (BAT) of DLC3.

  • 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 sensor assembly

  • ECM

  • Skid control ECU (brake actuator assembly)

  • Air conditioning amplifier assembly

  • Certification ECU (smart key ECU assembly)

  • Network gateway ECU (w/ Network gateway ECU)

  • Option connector (bus buffer ECU) (w/o Network gateway ECU)

  • Radio receiver assembly

  • Front steering control ECU (w/ VGRS system)

  • Yaw rate sensor

  • Headlight leveling ECU assembly (for Single Beam Headlight)

  • No. 1 CAN junction connector

  • No. 2 CAN junction connector

WIRING DIAGRAM

B00741LE03
B0073LLE05
B0076PLE01

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 60 seconds, and then drive the vehicle at a speed of 40 km/h (25 mph) or more for 5 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 TO +B IN CAN BUS LINE (NO. 1 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the O104 No. 1 CAN junction connector.

      B00735MC13
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b

      to No. 2 CAN Junction Connector

      (for V Bus)
      *c

      to Combination Meter Assembly

      (for V Bus)

      		 *d

      to Radio Receiver Assembly

      (for V Bus)
      *e

      to Airbag Sensor Assembly

      (for V Bus)

      		 *f

      to Yaw Rate Sensor

      (for V Bus)
      *g

      to Skid Control ECU (Brake Actuator Assembly)

      (for V Bus)

      		 *h

      to Steering Sensor

      (for V Bus)
      *i

      to DLC3

      (for V Bus)

      		 - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O104-1 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 2 CAN junction connector
      O104-11 (CANL) - O8-16 (BAT)
      O104-2 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Combination meter assembly
      O104-12 (CANL) - O8-16 (BAT)
      O104-3 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Radio receiver assembly
      O104-13 (CANL) - O8-16 (BAT)
      O104-4 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Airbag sensor assembly
      O104-14 (CANL) - O8-16 (BAT)
      O104-5 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Yaw rate sensor
      O104-15 (CANL) - O8-16 (BAT)
      O104-6 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Skid control ECU (brake actuator assembly)
      O104-16 (CANL) - O8-16 (BAT)
      O104-7 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Steering sensor
      O104-17 (CANL) - O8-16 (BAT)
      O104-8 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher DLC3
      O104-18 (CANL) - O8-16 (BAT)
      Result
      Result Proceed to
      OK A
      NG (No. 2 CAN junction connector main line) B
      NG (ECU or sensor bus line) C
      NG (DLC3 branch line) D

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    C

    GO TO STEP 3 Click here

    D

    REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3

    B

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


    1. Reconnect the O104 No. 1 CAN junction connector.

    2. Disconnect the O105 No. 2 CAN junction connector.

      B00735MC10
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b

      to No. 1 CAN Junction Connector

      (for V Bus)
      *c

      to Main Body ECU (Multiplex Network Body ECU)

      (for V Bus)

      		 *d

      to ECM

      (for V Bus)
      *e

      to Headlight Leveling ECU Assembly

      (for Single Beam Headlight)

      (for V Bus)

      		 *f

      to Network Gateway ECU

      (w/ Network Gateway ECU)

      (for V Bus)
      *g

      to Option Connector (Bus Buffer ECU)

      (w/o Network Gateway ECU)

      (for V Bus)

      		 *h

      to Air Conditioning Amplifier Assembly

      (for V Bus)
      *i

      to Front Steering Control ECU

      (w/ VGRS System)

      (for V Bus)

      		 *j

      to Certification ECU (Smart Key ECU Assembly)

      (for V Bus)
      *k

      to Power Steering ECU Assembly

      (for V Bus)

      		 - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O105-1 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 1 CAN junction connector
      O105-11 (CANL) - O8-16 (BAT)
      O105-2 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Main body ECU (multiplex network body ECU)
      O105-12 (CANL) - O8-16 (BAT)
      O105-3 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher ECM
      O105-13 (CANL) - O8-16 (BAT)
      O105-4 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Headlight leveling ECU assembly*1
      O105-14 (CANL) - O8-16 (BAT)
      O105-5 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Network gateway ECU*2
      O105-15 (CANL) - O8-16 (BAT)
      O105-5 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Option connector (bus buffer ECU)*3
      O105-15 (CANL) - O8-16 (BAT)
      O105-6 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Air conditioning amplifier assembly
      O105-16 (CANL) - O8-16 (BAT)
      O105-7 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Front steering control ECU*4
      O105-17 (CANL) - O8-16 (BAT)
      O105-8 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Certification ECU (smart key ECU assembly)
      O105-18 (CANL) - O8-16 (BAT)
      O105-10 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Power steering ECU assembly
      O105-20 (CANL) - O8-16 (BAT)

      • *1: for Single Beam Headlight

      • *2: w/ Network gateway ECU

      • *3: w/o Network gateway ECU

      • *4: w/ VGRS system

      Result
      Result Proceed to
      OK A
      NG (No. 1 CAN junction connector main line) B
      NG (ECU or sensor bus line) C

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

    C

  3. CHECK FOR SHORT TO +B IN CAN BUS LINE (ECU, SENSOR)


    1. Reconnect all wire harness connectors.

    2. Disconnect the ECU or sensor connected to the CAN bus line that is shorted to +B.

      Tech Tips

      If the ECU or sensor has multiple connectors, disconnect the connector that includes the CAN bus lines. To determine the ECU or sensor that is connected to the shorted bus line, refer to Terminals of ECU.

      Click here

    3. B0076CHC87
      *1 DLC3

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      O8-6 (CANH) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      O8-14 (CANL) - O8-16 (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.

      Result
      Result
      OK
      NG

    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR CAN BUS LINE OR CONNECTOR