CAN COMMUNICATION SYSTEM Check CAN Bus Line for Short to GND (LHD Models)

DTC Code DTC Name
Check CAN Bus Line for Short to GND (LHD Models)

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of the DLC3.

Symptom

Trouble Area

No resistance exists between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of DLC3.

  • Short in CAN main bus line

  • Short in CAN branch line

  • Combination meter assembly

  • Certification ECU (Smart key ECU assembly)*1

  • Steering sensor (Spiral cable with sensor sub-assembly)*2

  • Radio and display receiver assembly*3

  • Airbag sensor assembly

  • Power steering ECU assembly

  • Air conditioning amplifier assembly*4

  • Clearance warning ECU assembly*5

  • Engine stop and start ECU*6

  • Brake actuator assembly

  • Main body ECU (Multiplex network body ECU)

  • AFS ECU (Headlight swivel ECU assembly)*7

  • ECM

  • No. 1 CAN junction connector

  • No. 3 CAN junction connector

  • *1: w/ Entry and Start System

  • *2: w/ VSC

  • *3: for Radio and Display Type

  • *4: w/ Air Conditioning System

  • *5: w/ Simple Intelligent Parking Assist System

  • *6: w/ Stop and Start System

  • *7: w/ AFS (Adaptive Front-lighting System)

WIRING DIAGRAM

C274993E03
C274994E03

CAUTION / NOTICE / HINT

Note:

  • Before measuring the resistance of the CAN bus, turn the ignition 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 (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the ignition 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 ignition switch to ON and wait at least 31 seconds, and then drive the vehicle at a speed of 20 km/h (12 mph) 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

Tip:

  • Operating the ignition 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 GND IN CAN BUS LINE (NO. 3 CAN JUNCTION CONNECTOR)

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

    2. Disconnect the E57 No. 3 CAN junction connector.

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

      C275702C08

      *1

      DLC3

      -

      -

      *a

      Front view of wire harness connector

      (to No. 3 CAN Junction Connector)

      *b

      to Airbag Sensor Assembly

      *c

      to Air Conditioning Amplifier Assembly*1

      *d

      to Radio and Display Receiver Assembly*2

      *e

      to Combination Meter Assembly

      *f

      to No. 1 CAN Junction Connector

      *g

      to Certification ECU (Smart Key ECU Assembly)*3

      *h

      to Clearance Warning ECU Assembly*4

      *i

      to Engine Stop and Start ECU*5

      *j

      to Power Steering ECU Assembly

      *k

      to Steering Sensor (Spiral Cable with Sensor Sub-assembly)*6

      -

      -

      • *1: w/ Air Conditioning System

      • *2: for Radio and Display Type

      • *3: w/ Entry and Start System

      • *4: w/ Simple Intelligent Parking Assist System

      • *5: w/ Stop and Start System

      • *6: w/ VSC

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Connected to

      E57-1 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Airbag sensor assembly

      E57-12 (CANL) - E11-4 (CG)

      E57-2 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Air conditioning amplifier assembly*1

      E57-13 (CANL) - E11-4 (CG)

      E57-3 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Radio and display receiver assembly*2

      E57-14 (CANL) - E11-4 (CG)

      E57-4 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Combination meter assembly

      E57-15 (CANL) - E11-4 (CG)

      E57-5 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      No. 1 CAN junction connector

      E57-16 (CANL) - E11-4 (CG)

      E57-6 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Certification ECU (Smart key ECU assembly)*3

      E57-17 (CANL) - E11-4 (CG)

      E57-7 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Clearance warning ECU assembly*4

      E57-18 (CANL) - E11-4 (CG)

      E57-8 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Engine stop and start ECU*5

      E57-19 (CANL) - E11-4 (CG)

      E57-9 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Power steering ECU assembly

      E57-20 (CANL) - E11-4 (CG)

      E57-10 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Steering sensor (Spiral cable with sensor sub-assembly)*6

      E57-21 (CANL) - E11-4 (CG)

      • *1: w/ Air Conditioning System

      • *2: for Radio and Display Type

      • *3: w/ Entry and Start System

      • *4: w/ Simple Intelligent Parking Assist System

      • *5: w/ Stop and Start System

      • *6: w/ VSC

    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. 3 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU, SENSOR)Click here

    B

  2. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 1 CAN JUNCTION CONNECTOR)

    1. Disconnect the A32 No. 1 CAN junction connector.

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

      C275702C09

      *1

      DLC3

      -

      -

      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      *b

      to No. 3 CAN Junction Connector

      *c

      to DLC3

      *d

      to Main Body ECU (Multiplex Network Body ECU)

      *e

      to AFS ECU (Headlight Swivel ECU Assembly)*1

      *f

      to Brake Actuator Assembly

      *g

      to ECM

      -

      -

      *1: w/ AFS (Adaptive Front-lighting System)

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Connected to

      A32-1 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      No. 3 CAN junction connector

      A32-12 (CANL) - E11-4 (CG)

      A32-2 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      DLC3

      A32-13 (CANL) - E11-4 (CG)

      A32-3 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Main body ECU (Multiplex network body ECU)

      A32-14 (CANL) - E11-4 (CG)

      A32-4 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      AFS ECU (Headlight swivel ECU assembly)*1

      A32-15 (CANL) - E11-4 (CG)

      A32-5 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Brake actuator assembly

      A32-16 (CANL) - E11-4 (CG)

      A32-6 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      ECM

      A32-17 (CANL) - E11-4 (CG)

      *1: w/ AFS (Adaptive Front-lighting System)

    Result

    Result

    Proceed to

    OK

    A

    NG (No. 3 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

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - NO. 3 CAN JUNCTION CONNECTOR)

    D

    REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3

    C

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

    1. Reconnect all wire harness connectors (No. 1 CAN junction connector and No. 3 CAN junction connector).

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

      Tip:

      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. C151827C21

      *1

      DLC3

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E11-6 (CANH) - E11-4 (CG)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      E11-14 (CANL) - E11-4 (CG)
      Tip:

      If the resistance changes to 200 Ω 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 BRANCH LINES OR CONNECTOR