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) or 9 (CAXH) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) or 24 (CAXL) 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) or 9 (CAXH) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) or 24 (CAXL) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.
  • Short to ground in CAN main bus wire

  • Short to ground in CAN branch wire

  • Central gateway ECU (network gateway ECU)

  • Driving support ECU assembly*1

  • Forward recognition camera*1

  • Millimeter wave radar sensor assembly*1

  • Clearance warning ECU assembly

  • Television camera assembly

  • Blind spot monitor sensor RH*2

  • No. 4 CAN junction terminal

  • No. 3 CAN junction connector

  • No. 14 CAN junction connector

  • No. 15 CAN junction connector

*1: w/ Pre-collision System
*2: w/ Blind Spot Monitor System

WIRING DIAGRAM

B000XVPE06
B000UZ3E10

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 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

  • 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 engine 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. 3 CAN JUNCTION CONNECTOR)

    Tech Tips


    • Before disconnecting the connectors, make a note of where it is connected.

    • Reconnect the connector to its original position.


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

    2. Disconnect the No. 3 CAN junction connectors.

      B000Y4UC08
      *1 No. 3 CAN Junction Connector - -
      *a

      Rear view of wire harness connector

      (to No. 3 CAN Junction Connector)

      *b Front view of DLC3
      Wiring Color
      Code Color (CANH Side) Color (CANL Side) Connect to
      P109 BE W Central gateway ECU (network gateway ECU)
      P110 L W Millimeter wave radar sensor assembly (w/ Pre-collision System)
      P111 R W Driving support ECU assembly (w/ Pre-collision System)
      P112 G W Forward recognition camera (w/ Pre-collision System)
      P113 P W Central gateway ECU (network gateway ECU)
      P114 Y W No. 15 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
      P109-1 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      P109-2 (CANL) - P12-4 (CG)
      P110-1 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Millimeter wave radar sensor assembly*
      P110-2 (CANL) - P12-4 (CG)
      P111-1 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Driving support ECU assembly*
      P111-2 (CANL) - P12-4 (CG)
      P112-1 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Forward recognition camera*
      P112-2 (CANL) - P12-4 (CG)
      P113-1 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      P113-2 (CANL) - P12-4 (CG)
      P114-1 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 15 CAN junction connector
      P114-2 (CANL) - P12-4 (CG)
      *: w/ Pre-collision System
      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU [network gateway ECU] CAN main wire) B
      NG (Central gateway ECU [network gateway ECU] CAN branch wire) C
      NG (No. 15 CAN junction connector CAN main wire) D
      NG (Wire to ECU or sensor) E

    A
    C
    D
    E
    B
  2. CONNECT CONNECTOR


    1. Reconnect the No. 3 CAN junction connectors.

      Result
      Proceed to
      NEXT

    NEXT
  3. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 3 CAN JUNCTION CONNECTOR)


    1. B000W88C51
      *a

      Front view of wire harness connector

      (to Central Gateway ECU [Network Gateway ECU])

      *b Front view of DLC3

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P59-9 (CAXH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      P59-24 (CAXL) - P12-4 (CG)
      Result
      Result
      OK
      NG

    OK
    NG
  4. CONNECT CONNECTOR


    1. Reconnect the No. 3 CAN junction connectors.

      Result
      Proceed to
      NEXT

    NEXT
  5. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 3 CAN JUNCTION CONNECTOR)


    1. B000W88C52
      *a

      Front view of wire harness connector

      (to Central Gateway ECU [Network Gateway ECU])

      *b Front view of DLC3

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P59-18 (CA4H) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      P59-17 (CA4L) - P12-4 (CG)
      Result
      Result
      OK
      NG

    OK
    NG
  6. CONNECT CONNECTOR


    1. Reconnect the No. 3 CAN junction connectors.

      Result
      Proceed to
      NEXT

    NEXT
  7. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 15 CAN JUNCTION CONNECTOR)


    1. B000WKZC11
      *a

      Front view of wire harness connector

      (to No. 15 CAN Junction Connector)

      *b Front view of DLC3
      *c to No. 3 CAN Junction Connector
      *d to No. 14 CAN Junction Connector
      *e to Television Camera Assembly

      Disconnect the No. 15 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      X110-1 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 3 CAN junction connector
      X110-12 (CANL) - P12-4 (CG)
      X110-2 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 14 CAN junction connector
      X110-13 (CANL) - P12-4 (CG)
      X110-3 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Television camera assembly
      X110-14 (CANL) - P12-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (No. 3 CAN junction connector CAN main wire) B
      NG (No. 14 CAN junction connector CAN main wire) C
      NG (Wire to ECU or sensor) D

    A
    B
    D
    C
  8. CONNECT CONNECTOR


    1. Reconnect the X110 No. 15 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT
  9. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 14 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 14 CAN junction connector.

    2. B000WKZC12
      *a

      Front view of wire harness connector

      (to No. 14 CAN Junction Connector)

      *b Front view of DLC3
      *c to Clearance Warning ECU Assembly
      *d to Blind Spot Monitor Sensor RH (w/ Blind Spot Monitor System)
      *e to No. 15 CAN Junction Connector
      *f to No. 4 CAN Junction Terminal

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      X109-1 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Clearance warning ECU assembly
      X109-12 (CANL) - P12-4 (CG)
      X109-2 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Blind spot monitor sensor RH*
      X109-13 (CANL) - P12-4 (CG)
      X109-3 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 15 CAN junction connector
      X109-14 (CANL) - P12-4 (CG)
      X109-4 (CANH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 4 CAN junction terminal
      X109-15 (CANL) - P12-4 (CG)
      *: w/ Blind Spot Monitor System
      Result
      Result Proceed to
      OK A
      NG (No. 15 CAN junction connector CAN main wire) B
      NG (Wire to ECU or sensor) C

    A
    B
    C
  10. CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)


    1. B000YSNC31
      *a

      Component with harness connected

      (Central Gateway ECU [Network Gateway ECU])

      *b Front view of DLC3

      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.

      Standard Resistance
      Tester Connection Condition Specified Condition
      P59-9 (CAXH) - P12-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      P59-24 (CAXL) - P12-4 (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
      Result
      OK
      NG

    OK
    NG