CAN COMMUNICATION SYSTEM Check Bus 2 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
No resistance exists 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 ground in CAN main bus line

  • Short to ground in CAN branch line

  • Central gateway ECU (network gateway ECU)

  • ECM

  • Combination meter assembly

  • Air conditioning amplifier assembly

  • Engine stop and start ECU (w/ Stop and Start System)

  • Power steering ECU assembly

  • Certification ECU (smart key ECU assembly)

  • Airbag sensor assembly

  • Yaw rate sensor

  • Main body ECU (multiplex network body ECU)

  • Skid control ECU (brake actuator assembly)

  • Stereo component equalizer assembly (w/ ASC System)

  • Steering sensor

  • Front steering control ECU (w/ VGRS System)

  • No. 1 CAN junction connector

  • No. 2 CAN junction connector

WIRING DIAGRAM

Figure 1. for LHD:

B003WAKE01
B003X7VE02

Figure 2. for RHD:

B003T60E01
B003WH1E02

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

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

    DTC check procedure: Turn the ignition switch to ON 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

  • Before replacing the ECM, main body ECU (multiplex network body ECU) or certification ECU (smart key ECU assembly), refer to Service Bulletin.

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. 1 CAN JUNCTION CONNECTOR) Click here

    A

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


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

    2. Disconnect the K109 No. 1 CAN junction connector.

      B003TBOC03
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b to No. 2 CAN Junction Connector
      *c to Combination Meter Assembly *d

      to Engine Stop and Start ECU

      (w/ Stop and Start System)
      *e to Central Gateway ECU (Network Gateway ECU) *f to Air Conditioning Amplifier Assembly
      *g

      to Stereo Component Equalizer Assembly

      (w/ ASC System)

      		 *h to Certification ECU (Smart Key ECU Assembly)
      *i 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
      K109-1 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 2 CAN junction connector
      K109-11 (CANL) - K9-4 (CG)
      K109-2 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Combination meter assembly
      K109-12 (CANL) - K9-4 (CG)
      K109-3 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU*1
      K109-13 (CANL) - K9-4 (CG)
      K109-4 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K109-14 (CANL) - K9-4 (CG)
      K109-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly
      K109-15 (CANL) - K9-4 (CG)
      K109-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Stereo component equalizer assembly*2
      K109-16 (CANL) - K9-4 (CG)
      K109-7 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      K109-17 (CANL) - K9-4 (CG)
      K109-9 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
      K109-19 (CANL) - K9-4 (CG)

      • *1: w/ Stop and Start System

      • *2: w/ ASC System

      Result
      Result Proceed to
      OK A
      NG (Line to No. 2 CAN junction connector) B
      NG (Line to central gateway ECU (network gateway ECU)) C
      NG (Line to ECU or sensor) D

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) Click here

    D

    GO TO STEP 8 Click here

    B

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


    1. Reconnect the K109 No. 1 CAN junction connector.

    2. Disconnect the K110 No. 2 CAN junction connector.

      B003UG4C91
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b to No. 1 CAN Junction Connector
      *c to Main Body ECU (Multiplex Network Body ECU) *d to ECM
      *e to Airbag Sensor Assembly *f to Yaw Rate Sensor
      *g to Steering Sensor *h to Skid Control ECU (Brake Actuator Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K110-1 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 1 CAN junction connector
      K110-11 (CANL) - K9-4 (CG)
      K110-2 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      K110-12 (CANL) - K9-4 (CG)
      K110-3 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher ECM
      K110-13 (CANL) - K9-4 (CG)
      K110-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag sensor assembly
      K110-15 (CANL) - K9-4 (CG)
      K110-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Yaw rate sensor
      K110-16 (CANL) - K9-4 (CG)
      K110-9 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Steering sensor
      K110-19 (CANL) - K9-4 (CG)
      K110-10 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Skid control ECU (brake actuator assembly)
      K110-20 (CANL) - K9-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (Line to No. 1 CAN junction connector) B
      NG (Line to ECU or sensor) C

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

    C

    GO TO STEP 8 Click here

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


    1. Reconnect the K109 No. 1 CAN junction connector.

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

      B003TGFC14
      *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
      K141-18 (CA4H) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-17 (CA4L) - K9-4 (CG)
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

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

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


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

    2. Disconnect the K109 No. 1 CAN junction connector.

      B003UG4C92
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b to No. 2 CAN Junction Connector
      *c to Combination Meter Assembly *d

      to Engine Stop and Start ECU

      (w/ Stop and Start System)
      *e to Airbag Sensor Assembly *f to Yaw Rate Sensor
      *g to Skid Control ECU (Brake Actuator Assembly) *h to Steering Sensor

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K109-1 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 2 CAN junction connector
      K109-11 (CANL) - K9-4 (CG)
      K109-2 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Combination meter assembly
      K109-12 (CANL) - K9-4 (CG)
      K109-3 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU*
      K109-13 (CANL) - K9-4 (CG)
      K109-4 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag sensor assembly
      K109-14 (CANL) - K9-4 (CG)
      K109-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Yaw rate sensor
      K109-15 (CANL) - K9-4 (CG)
      K109-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Skid control ECU (brake actuator assembly)
      K109-16 (CANL) - K9-4 (CG)
      K109-7 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Steering sensor
      K109-17 (CANL) - K9-4 (CG)

      • *: w/ Stop and Start System

      Result
      Result Proceed to
      OK A
      NG (Line to No. 2 CAN junction connector) B
      NG (Line to ECU or sensor) C

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    C

    GO TO STEP 8 Click here

    B

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


    1. Reconnect the K109 No. 1 CAN junction connector.

    2. Disconnect the K110 No. 2 CAN junction connector.

      B003TBOC04
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b to No. 1 CAN Junction Connector
      *c to Main Body ECU (Multiplex Network Body ECU) *d to ECM
      *e to Central Gateway ECU (Network Gateway ECU) *f to Air Conditioning Amplifier Assembly
      *g

      to Front Steering Control ECU

      (w/ VGRS System)

      		 *h to Certification ECU (Smart Key ECU Assembly)
      *i

      to Stereo Component Equalizer Assembly

      (w/ ASC System)

      		 *j 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
      K110-1 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 1 CAN junction connector
      K110-11 (CANL) - K9-4 (CG)
      K110-2 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      K110-12 (CANL) - K9-4 (CG)
      K110-3 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher ECM
      K110-13 (CANL) - K9-4 (CG)
      K110-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K110-15 (CANL) - K9-4 (CG)
      K110-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly
      K110-16 (CANL) - K9-4 (CG)
      K110-7 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Front steering control ECU*1
      K110-17 (CANL) - K9-4 (CG)
      K110-8 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      K110-18 (CANL) - K9-4 (CG)
      K110-9 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Stereo component equalizer assembly*2
      K110-19 (CANL) - K9-4 (CG)
      K110-10 (CANH) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
      K110-20 (CANL) - K9-4 (CG)

      • *1: w/ VGRS System

      • *2: w/ ASC System

      Result
      Result Proceed to
      OK A
      NG (Line to No. 1 CAN junction connector) B
      NG (Line to central gateway ECU (network gateway ECU)) C
      NG (Line to ECU or sensor) D

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

    D

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

    C

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


    1. Reconnect the K110 No. 2 CAN junction connector.

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

      B003TGFC15
      *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
      K141-18 (CA4H) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-17 (CA4L) - 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 (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 2 CAN JUNCTION CONNECTOR)

  8. 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.

      B003X8AC17
      *1 DLC3 - -
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      K141-18 (CA4H) - K9-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K141-17 (CA4L) - 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