CAN COMMUNICATION SYSTEM Check Bus 2 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 23 (CA1H) and 8 (CA1L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom Trouble Area
Resistance between terminals 23 (CA1H) and 8 (CA1L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

  • Short in CAN main bus wire

  • Short in CAN branch wire

  • Central gateway ECU (network gateway ECU)

  • Shift control ECU

  • Engine stop and start ECU*

  • ECM

  • No. 9 CAN junction connector

  • No. 13 CAN junction connector
*: w/ Stop and Start System

WIRING DIAGRAM

B006BEXE02

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 IN CAN BUS WIRES (NO. 9 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the G129 No. 9 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
      G129-12 (CANH) - G129-1 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU)
      G129-13 (CANH) - G129-2 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU*
      G129-14 (CANH) - G129-3 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Shift control ECU
      G129-16 (CANH) - G129-5 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 13 CAN junction connector
      *: w/ Stop and Start System
      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU [network gateway ECU] CAN main wire) B
      NG (No. 13 CAN junction connector CAN main wire) C
      NG (Wire to ECU or sensor) D

    A

    REPLACE NO. 9 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT IN CAN BUS WIRES (NO. 13 CAN JUNCTION CONNECTOR) Click here

    D

    GO TO STEP 5 Click here

    B

  2. CHECK FOR SHORT IN CAN BUS WIRES (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 9 CAN JUNCTION CONNECTOR)


    1. Reconnect the G129 No. 9 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
      G66-23 (CA1H) - G66-8 (CA1L) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 9 CAN JUNCTION CONNECTOR)

  3. CHECK FOR SHORT IN CAN BUS WIRES (NO. 13 CAN JUNCTION CONNECTOR)


    1. Reconnect the G129 No. 9 CAN junction connector.

    2. Disconnect the L118 No. 13 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
      L118-1 (CANH) - L118-7 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
      L118-3 (CANH) - L118-9 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 9 CAN junction connector
      L118-4 (CANH) - L118-10 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Sub-battery with control assembly
      Result
      Result Proceed to
      OK A
      NG (ECM CAN main wire) B
      NG (No. 9 CAN junction connector CAN main wire) C
      NG (Wire to ECU or sensor) D

    A

    REPLACE NO. 13 CAN JUNCTION CONNECTOR

    C

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 13 CAN JUNCTION CONNECTOR - NO. 9 CAN JUNCTION CONNECTOR)

    D

    CHECK FOR SHORT IN CAN BUS WIRES (ECU, SENSOR) Click here

    B

  4. CHECK FOR SHORT IN CAN BUS WIRES (ECM - NO. 13 CAN JUNCTION CONNECTOR)


    1. Reconnect the L118 No. 13 CAN junction connector.

    2. Disconnect the A56*1 or A95*2 ECM connector.


      • *1: for 8GR-FKS

      • *2: for V35A-FTS

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

      Standard Resistance
      for 8GR-FKS
      Tester Connection Condition Specified Condition
      A56-13 (CANH) - A56-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      for V35A-FTS
      Tester Connection Condition Specified Condition
      A95-18 (CANH) - A95-17 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM for 8GR-FKS: Click here
    REPLACE ECM for V35A-FTS: Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (ECM - NO. 13 CAN JUNCTION CONNECTOR)

  5. CHECK FOR SHORT IN CAN BUS WIRES (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 short circuited branch wire is connected.

      Click here

    3. B006FRUC20
      *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
      G66-23 (CA1H) - G66-8 (CA1L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω

      Tech Tips

      If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECU OR SENSOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR