CAN COMMUNICATION SYSTEM Check Bus 4 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 terminal 22 (CA2H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 7 (CA2L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom Trouble Area
No resistance exists between terminal 22 (CA2H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 7 (CA2L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

  • Short to ground in CAN main bus line

  • Short to ground in CAN branch line

  • Central gateway ECU (network gateway ECU)

  • Skid control ECU (brake actuator assembly)

  • Power steering ECU assembly

  • Front steering control ECU

  • Absorber control ECU

  • No. 8 CAN junction connector

  • No. 14 junction connector

WIRING DIAGRAM

B003UUKE01

CAUTION / NOTICE / HINT

Note


  • 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

  • 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

  • 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) and wait for at least 60 seconds.

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

    Click here

Tech Tips


  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.

  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE


  1. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 14 JUNCTION CONNECTOR)


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

    2. Disconnect the Q57 No. 14 junction connector.

      B003X4RC11
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 14 Junction Connector)

      		 *b to No. 8 CAN Junction Connector
      *c to Power Steering ECU Assembly - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      Q57-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 8 CAN junction connector
      Q57-16 (CANL) - K9-4 (CG)
      Q57-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
      Q57-17 (CANL) - K9-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (Line to No. 8 CAN junction connector) B
      NG (Line to ECU or sensor) C

    A

    REPLACE NO. 14 JUNCTION CONNECTOR

    C

    GO TO STEP 4 Click here

    B

  2. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 8 CAN JUNCTION CONNECTOR)


    1. Reconnect the Q57 No. 14 junction connector.

    2. Disconnect the K116 No. 8 CAN junction connector.

      B003X4RC12
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 8 CAN Junction Connector)

      		 *b to Front Steering Control ECU
      *c to Skid Control ECU (Brake Actuator Assembly) *d to No. 14 Junction Connector
      *e to Absorber Control ECU *f to Central Gateway ECU (Network Gateway ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K116-1 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Front steering control ECU
      K116-12 (CANL) - K9-4 (CG)
      K116-3 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Skid control ECU (brake actuator assembly)
      K116-14 (CANL) - K9-4 (CG)
      K116-4 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 14 junction connector
      K116-15 (CANL) - K9-4 (CG)
      K116-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Absorber control ECU
      K116-16 (CANL) - K9-4 (CG)
      K116-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K116-17 (CANL) - K9-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (Line to No. 14 junction connector) B
      NG (Line to central gateway ECU (network gateway ECU)) C
      NG (Line to ECU or sensor) D

    A

    REPLACE NO. 8 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 14 JUNCTION CONNECTOR)

    D

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

    C

  3. CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Reconnect the K116 No. 8 CAN junction connector.

    2. Disconnect the K141 central gateway ECU (network gateway ECU) connector.

      B003TGFC17
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

      		 - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K141-22 (CA2H) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-7 (CA2L) - K9-4 (CG)
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

  4. CHECK FOR SHORT TO GND IN CAN BUS LINE (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 bus line shorted to GND is connected.

      Click here

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

      B003X8AC19
      *1 DLC3 - -
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      K141-22 (CA2H) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-7 (CA2L) - K9-4 (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 CAN BUS LINE OR CONNECTOR