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

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

  • FC converter assembly

  • Network gateway ECU

  • Spiral cable with sensor sub-assembly

  • Certification ECU (smart key ECU assembly)

  • Airbag ECU assembly

  • Power steering ECU assembly

  • Air conditioning amplifier assembly

  • Main body ECU (multiplex network body ECU)

  • Integration control and panel assembly

  • Radio and display receiver assembly

  • FC control ECU

  • EV control ECU

  • Skid control ECU (brake booster with master cylinder assembly)

  • No. 2 CAN junction connector

  • No. 3 CAN junction connector

WIRING DIAGRAM

A01MH5ZE01
A01MJCVE01
A01MGCQE01

CAUTION / NOTICE / HINT

Note


  • 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 negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary 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 power switch on (IG) and wait at least 2 minutes, and then drive the vehicle at a speed of 36 km/h (22 mph) or more for 300 seconds 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

  • If the main body ECU (multiplex network body ECU) is replaced, refer to Service Bulletin.

Tech Tips


  • Operating the power 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 (-) auxiliary battery terminal.

    2. Disconnect the No. 3 CAN junction connector.

      A01MJJSC04
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 3 CAN Junction Connector)

      		 *b to Power Steering ECU Assembly
      *c to Certification ECU (Smart Key ECU Assembly) *d to Radio and Display Receiver Assembly
      *e to Spiral Cable with Sensor Sub-assembly *f to No. 2 CAN Junction Connector
      *g to Network Gateway ECU *h to DLC3
      *i to Combination Meter Assembly *j to Integration Control and Panel Assembly

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      G85-1 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power steering ECU assembly
      G85-11 (CANL) - G8-4 (CG)
      G85-2 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      G85-12 (CANL) - G8-4 (CG)
      G85-3 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Radio and display receiver assembly
      G85-13 (CANL) - G8-4 (CG)
      G85-4 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Spiral cable with sensor sub-assembly
      G85-14 (CANL) - G8-4 (CG)
      G85-5 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 2 CAN junction connector
      G85-15 (CANL) - G8-4 (CG)
      G85-6 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Network gateway ECU
      G85-16 (CANL) - G8-4 (CG)
      G85-7 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher DLC3
      G85-17 (CANL) - G8-4 (CG)
      G85-8 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Combination meter assembly
      G85-18 (CANL) - G8-4 (CG)
      G85-9 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Integration control and panel assembly
      G85-19 (CANL) - G8-4 (CG)
      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. 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. 2 CAN JUNCTION CONNECTOR)


    1. Reconnect the G85 No. 3 CAN junction connector.

    2. Disconnect the No. 2 CAN junction connector.

      A01MGETC04
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b to Skid Control ECU (Brake Booster with Master Cylinder Assembly)
      *c to FC Control ECU *d to No. 3 CAN Junction Connector
      *e to EV Control ECU *f to FC Converter Assembly
      *g to Airbag ECU Assembly *h to Air Conditioning Amplifier Assembly
      *i to Main Body ECU (Multiplex Network Body ECU) - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      G84-1 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Skid control ECU (brake booster with master cylinder assembly)
      G84-11 (CANL) - G8-4 (CG)
      G84-2 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher FC control ECU
      G84-12 (CANL) - G8-4 (CG)
      G84-3 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 3 CAN junction connector
      G84-13 (CANL) - G8-4 (CG)
      G84-5 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher EV control ECU
      G84-15 (CANL) - G8-4 (CG)
      G84-6 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher FC converter assembly
      G84-16 (CANL) - G8-4 (CG)
      G84-7 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Airbag ECU assembly
      G84-17 (CANL) - G8-4 (CG)
      G84-8 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Air conditioning amplifier assembly
      G84-18 (CANL) - G8-4 (CG)
      G84-9 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      G84-19 (CANL) - G8-4 (CG)
      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. 2 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 2 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.

    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.

      Click here

    3. A01MHX3C02
      *1 DLC3

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G8-6 (CANH) - G8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G8-14 (CANL) - G8-4 (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