CAN COMMUNICATION SYSTEM Check Bus 3 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 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom Trouble Area
No resistance exists between terminal 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 21 (CA3L) 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

  • Telematics transceiver (w/ Telematics Transceiver)

  • Radio receiver assembly (w/ Navigation System or Audio and Visual System)

  • Central gateway ECU (network gateway ECU)

  • Option connector (bus buffer ECU) (for LHD)

  • No. 7 CAN junction connector (for LHD)

  • No. 8 CAN junction connector (for RHD)

WIRING DIAGRAM

Figure 1. for LHD:

B003VNIE01

Figure 2. for RHD:

B003W8DE01

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 31 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 VEHICLE TYPE


    1. Check vehicle type.

      Result
      Result Proceed to
      for LHD A
      for RHD B

    B

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

    A

  2. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the K115 No. 7 CAN junction connector.

      B003X4RC07
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 7 CAN Junction Connector)

      		 *b to Central Gateway ECU (Network Gateway ECU)
      *c

      to Telematics Transceiver

      (w/ Telematics Transceiver)

      		 *d

      to Radio Receiver Assembly

      (w/ Navigation System or Audio and Visual System)
      *e to Option Connector (Bus Buffer ECU) - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K115-7 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K115-18 (CANL) - K9-4 (CG)
      K115-8 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Telematics transceiver*1
      K115-19 (CANL) - K9-4 (CG)
      K115-9 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Radio receiver assembly*2
      K115-20 (CANL) - K9-4 (CG)
      K115-10 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Option connector (bus buffer ECU)
      K115-21 (CANL) - K9-4 (CG)
      K115-11 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K115-22 (CANL) - K9-4 (CG)

      • *1: w/ Telematics Transceiver

      • *2: w/ Navigation System or Audio and Visual System

      Result
      Result Proceed to
      OK A
      NG (Line to central gateway ECU (network gateway ECU)) B
      NG (Line to ECU or sensor) C

    A

    REPLACE NO. 7 CAN JUNCTION CONNECTOR

    C

    GO TO STEP 6 Click here

    B

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


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

      B003TGFC12
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

      		 - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K141-6 (CA3H) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-21 (CA3L) - K9-4 (CG)
      K141-19 (CAYH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-20 (CAYL) - K9-4 (CG)
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

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


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

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

      B003X4RC08
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 8 CAN Junction Connector)

      		 *b to Central Gateway ECU (Network Gateway ECU)
      *c

      to Radio Receiver Assembly

      (w/ Navigation System or Audio and Visual System)

      		 - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K116-7 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K116-18 (CANL) - K9-4 (CG)
      K116-9 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Radio receiver assembly*
      K116-20 (CANL) - K9-4 (CG)
      K116-11 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K116-22 (CANL) - K9-4 (CG)

      • *: w/ Navigation System or Audio and Visual System

      Result
      Result Proceed to
      OK A
      NG (Line to central gateway ECU (network gateway ECU)) B
      NG (Line to ECU or sensor) C

    A

    REPLACE NO. 8 CAN JUNCTION CONNECTOR

    C

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

    B

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


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

      B003TGFC12
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

      		 - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K141-6 (CA3H) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-21 (CA3L) - K9-4 (CG)
      K141-19 (CAYH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-20 (CAYL) - K9-4 (CG)
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

  6. 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.

      B003X8AC15
      *1 DLC3 - -
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      K141-6 (CA3H) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-21 (CA3L) - 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