CAN COMMUNICATION SYSTEM(w/o Central Gateway ECU) Check CAN Bus Line for Short to GND (RHD 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)

  • Radio and display receiver assembly*2

  • Airbag sensor assembly

  • Power steering ECU assembly

  • Air conditioning amplifier assembly*3

  • Clearance warning ECU assembly*4

  • Engine stop and start ECU*5

  • Brake actuator assembly

  • Main body ECU (Multiplex network body ECU)

  • ECM

  • No. 1 CAN junction connector

  • No. 3 CAN junction connector

WIRING DIAGRAM

A01D4IPE03
A01D4DGE03

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.

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  • 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.

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  • 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.

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Tech Tips


  • 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.

      A01D4B9C04
      *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 Power Steering ECU Assembly *j to Steering Sensor (Spiral Cable with Sensor Sub-assembly)
      *k to DLC3 - -

      • *1: w/ Air Conditioning System

      • *2: for Radio and Display Type

      • *3: w/ Entry and Start System

      • *4: w/ Simple Intelligent Parking Assist System

      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)
      E57-9 (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)
      E57-21 (CANL) - E11-4 (CG)
      E57-11 (CANH) - E11-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher DLC3
      E57-22 (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

      Result
      Result Proceed to
      OK A
      NG (No. 1 CAN junction connector main line) B
      NG (ECU or sensor bus line) C
      NG (DLC3 branch line) D

    A

    REPLACE NO. 3 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 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.

      A01D4B9C05
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b to No. 3 CAN Junction Connector
      *c to Engine Stop and Start ECU*1 *d to Main Body ECU (Multiplex Network Body ECU)
      *e to Brake Actuator Assembly *f to ECM

      *1: w/ Stop and start 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 Engine stop and start ECU*1
      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)
      A32-5 (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/ Stop and start system

      Result
      Result Proceed to
      OK A
      NG (No. 3 CAN junction connector main line) B
      NG (ECU or sensor bus line) C

    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)

    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.

      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.

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    3. A01D67LC21
      *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)

      Tech Tips

      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