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)

  • ECM

  • Sub-battery with control assembly

  • Shift control ECU

  • No. 6 CAN junction connector

  • No. 18 CAN junction connector

WIRING DIAGRAM

B000USCE03

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 (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 18 CAN JUNCTION CONNECTOR)


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

    2. B000VFDC14
      *a

      Front view of wire harness connector

      (to Central Gateway ECU [Network Gateway ECU])

      Disconnect the 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
      P59-23 (CA1H) - P59-8 (CA1L) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

  2. CONNECT CONNECTOR


    1. Reconnect the P59 central gateway ECU (network gateway ECU) connector.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR SHORT IN CAN BUS WIRES (ECM - NO. 6 CAN JUNCTION CONNECTOR)


    1. Disconnect the ECM connector.

    2. B000V8DC05
      *a

      Front view of wire harness connector

      (to ECM)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A58-13 (CANH) - A58-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

  4. CONNECT CONNECTOR


    1. Reconnect the A58 ECM connector.

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK FOR SHORT IN CAN BUS WIRES (NO. 6 CAN JUNCTION CONNECTOR)


    1. B000UFYC31
      *a

      Front view of wire harness connector

      (to No. 6 CAN Junction Connector)
      *b to Shift Control ECU
      *c to ECM
      *d to No. 18 CAN Junction Connector

      Disconnect the No. 6 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
      P124-1 (CANH) - P124-12 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Shift control ECU
      P124-2 (CANH) - P124-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
      P124-3 (CANH) - P124-14 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 18 CAN junction connector
      Result
      Result Proceed to
      OK A
      NG (ECM CAN main wire) B
      NG (No. 18 CAN junction connector CAN main wire) C
      NG (Wire to ECU or sensor) D

    A

    REPLACE NO. 6 CAN JUNCTION CONNECTOR

    B

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

    D

    GO TO STEP 8 Click here

    C

  6. CONNECT CONNECTOR


    1. Reconnect the P124 No. 6 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

  7. CHECK FOR SHORT IN CAN BUS WIRES (NO. 18 CAN JUNCTION CONNECTOR)


    1. B000UFYC12
      *a

      Front view of wire harness connector

      (to No. 18 CAN Junction Connector)
      *b to No. 6 CAN Junction Connector
      *c to Central Gateway ECU (Network Gateway ECU)
      *d to Sub-battery with Control Assembly

      Disconnect the No. 18 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
      b10-1 (CANH) - b10-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 6 CAN junction connector
      b10-2 (CANH) - b10-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU)
      b10-3 (CANH) - b10-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Sub-battery with control assembly
      Result
      Result Proceed to
      OK A
      NG (No. 6 CAN junction connector CAN main wire) B
      NG (Central gateway ECU [network gateway ECU] CAN main wire) C
      NG (Wire to ECU or sensor) D

    A

    REPLACE NO. 18 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 18 CAN JUNCTION CONNECTOR - NO. 6 CAN JUNCTION CONNECTOR)

    C

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 18 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU])

    D

  8. 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 line is connected.

      Click here

    3. B000XJRC08
      *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
      P59-23 (CA1H) - P59-8 (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
      Result
      OK
      NG

    OK

    REPLACE ECU OR SENSOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR