CAN COMMUNICATION SYSTEM Check Bus 1 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 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom Trouble Area
There is no resistance between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

  • Short to GND in CAN main bus wire

  • Short to GND in CAN branch wire

  • Central gateway ECU (network gateway ECU)

  • Object recognition camera*1

  • Forward recognition camera*2

  • Driving support ECU assembly*1, *2

  • Millimeter wave radar sensor assembly*1, *2

  • Front side radar sensor RH*1

  • Seat belt control ECU*1

  • Parking assist ECU*3

  • Clearance warning ECU assembly

  • Rear television camera assembly

  • Blind spot monitor sensor RH*4

  • No. 3 CAN junction terminal

  • No. 9 CAN junction terminal

  • No. 6 CAN junction connector

  • No. 7 CAN junction connector

  • No. 16 CAN junction connector
*1: w/ Pre-collision System (for Stereo Camera Type)
*2: w/ Pre-collision System (for Mono Camera Type)
*3: w/ Panoramic View Monitor System
*4: w/ Blind Spot Monitor System

WIRING DIAGRAM

B004VQCE01
B004WN7E07

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

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 power 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 (-) 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

  • Some parts must be initialized and set when replacing or removing and installing parts.

    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 for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes 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 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 WIRE (NO. 6 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the G125 No. 6 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      G125-7 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 16 CAN junction connector
      G125-1 (CANL) - G20-4 (CG)
      G125-8 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Driving support ECU assembly*1, *3
      G125-2 (CANL) - G20-4 (CG)
      G125-9 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Millimeter wave radar sensor assembly*3
      G125-3 (CANL) - G20-4 (CG)
      G125-10 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 7 CAN junction connector
      G125-4 (CANL) - G20-4 (CG)
      G125-11 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      • Central gateway ECU (network gateway ECU)*1

      • Driving support ECU assembly*2, *3
      G125-5 (CANL) - G20-4 (CG)
      G125-12 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Parking assist ECU*4
      G125-6 (CANL) - G20-4 (CG)
      *1: for RHD
      *2: for LHD
      *3: w/ Pre-collision System
      *4: w/ Panoramic View Monitor System
      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU [network gateway ECU] CAN branch wire) B
      NG (No. 5 CAN junction connector CAN main wire) C
      NG (No. 7 CAN junction connector CAN main wire) D
      NG (Wire to ECU or sensor) E

    A

    REPLACE NO. 6 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 16 CAN JUNCTION CONNECTOR) Click here

    D

    CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 7 CAN JUNCTION CONNECTOR) Click here

    E

    GO TO STEP 6 Click here

    B

  2. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 6 CAN JUNCTION CONNECTOR)


    1. Reconnect the G125 No. 6 CAN junction connector.

    2. Disconnect the G66 central gateway ECU (network gateway ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G66-18 (CA4H) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G66-17 (CA4L) - G20-4 (CG)
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 6 CAN JUNCTION CONNECTOR)

  3. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 16 CAN JUNCTION CONNECTOR)


    1. Reconnect the G125 No. 6 CAN junction connector.

    2. Disconnect the L123 No. 16 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L123-1 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 6 CAN junction connector
      L123-11 (CANL) - G20-4 (CG)
      L123-2 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 3 CAN junction terminal
      L123-12 (CANL) - G20-4 (CG)
      L123-3 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Clearance warning ECU assembly
      L123-13 (CANL) - G20-4 (CG)
      L123-5 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Rear television camera assembly
      L123-15 (CANL) - G20-4 (CG)
      L123-6 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Blind spot monitor sensor RH*1
      L123-16 (CANL) - G20-4 (CG)
      L123-7 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Seat belt control ECU*2
      L123-17 (CANL) - G20-4 (CG)
      *1: w/ Blind Spot Monitor System
      *2: w/ Pre-collision System (for Stereo Camera Type)
      Result
      Result Proceed to
      OK A
      NG (No. 6 CAN junction connector CAN main wire) B
      NG (Wire to ECU or sensor) C

    A

    REPLACE NO. 16 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 16 CAN JUNCTION CONNECTOR - NO. 6 CAN JUNCTION CONNECTOR)

    C

    GO TO STEP 6 Click here

  4. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 7 CAN JUNCTION CONNECTOR)


    1. Reconnect the G125 No. 6 CAN junction connector.

    2. Disconnect the G126 No. 7 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      G126-7 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)*1
      G126-1 (CANL) - G20-4 (CG)
      G126-8 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 9 CAN junction terminal
      G126-2 (CANL) - G20-4 (CG)
      G126-9 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      • Forward recognition camera*2

      • Object recognition camera*3
      G126-3 (CANL) - G20-4 (CG)
      G126-10 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Swing grille actuator assembly
      G126-4 (CANL) - G20-4 (CG)
      G126-11 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Front side radar sensor RH*3
      G126-5 (CANL) - G20-4 (CG)
      G126-12 (CANH) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 6 CAN junction connector
      G126-6 (CANL) - G20-4 (CG)
      *1: for LHD
      *2: w/ Pre-collision System (for Mono Camera Type)
      *3: w/ Pre-collision System (for Stereo Camera Type)
      Result
      Result Proceed to
      OK A
      NG (No. 6 CAN junction connector CAN main wire) B
      NG (Central gateway ECU [network gateway ECU] CAN branch wire) C
      NG (Wire to ECU or sensor) D

    A

    REPLACE NO. 7 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 6 CAN JUNCTION CONNECTOR)

    D

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

    C

  5. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 7 CAN JUNCTION CONNECTOR)


    1. Reconnect the G126 No. 7 CAN junction connector.

    2. Disconnect the G66 central gateway ECU (network gateway ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G66-18 (CA4H) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G66-17 (CA4L) - G20-4 (CG)
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 7 CAN JUNCTION CONNECTOR)

  6. CHECK FOR SHORT TO GND IN CAN BUS WIRE (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 wire shorted to GND is connected.

      Click here

    3. B004T3JC19
      *a

      Component with harness connected

      (Central Gateway ECU [Network Gateway ECU])

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G66-18 (CA4H) - G20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G66-17 (CA4L) - G20-4 (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.

      • If the resistance does not become normal when the connector is disconnected from the ECU or sensor, check for a short to ground in the wire harness and repair or replace the wire harness or connector if necessary.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECU OR SENSOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR