CAN COMMUNICATION SYSTEM Open in Bus 3 Main Bus Line

DESCRIPTION

There may be an open circuit in one of the CAN main bus lines when the resistance between terminals 6 (CA3H) and 21 (CA3L) of the central gateway ECU (network gateway ECU) is 70 Ω or higher.

Symptom Trouble Area
Resistance between terminals 6 (CA3H) and 21 (CA3L) of central gateway ECU (network gateway ECU) is 70 Ω or higher.

  • CAN main bus lines or connector

  • Central gateway ECU (network gateway ECU)

  • No. 7 CAN junction connector (for LHD)

  • No. 8 CAN junction connector (for RHD)

This malfunction is not related to the lines of a CAN branch or to ECUs or sensors connected to a CAN branch.

WIRING DIAGRAM

Figure 1. for LHD:

B003T7LE01
*1 CAYH
*2 CAYL
*3 No. 7 CAN Junction Connector
*4 Central Gateway ECU (Network Gateway ECU)

Figure 2. for RHD:

B003T7LE02
*1 CAYH
*2 CAYL
*3 No. 8 CAN Junction Connector
*4 Central Gateway ECU (Network Gateway ECU)

CAUTION / NOTICE / HINT

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 engine switch on (IG) and wait for at least 31 seconds.

  • 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 VEHICLE TYPE


    1. Check vehicle type.

      Result
      Result Proceed to
      for LHD A
      for RHD B

    B

    CHECK FOR OPEN IN CAN BUS LINES (NO. 8 CAN JUNCTION CONNECTOR) Click here

    A

  2. CHECK FOR OPEN IN CAN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR)


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

    2. B003W9WC08
      *a

      Front view of wire harness connector

      (to No. 7 CAN Junction Connector)
      *b to Central Gateway ECU (Network Gateway ECU)

      Disconnect the K115 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
      K115-7 (CANH) - K115-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU)
      K115-11 (CANH) - K115-22 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU)
      Result
      Result
      OK
      NG

    OK

    REPLACE NO. 7 CAN JUNCTION CONNECTOR

    NG

  3. CHECK FOR OPEN IN CAN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 7 CAN JUNCTION CONNECTOR)


    1. Reconnect the K115 No. 7 CAN junction connector.

    2. B003X08C21
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

      Disconnect the K141 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
      K141-6 (CA3H) - K141-19 (CAYH) Cable disconnected from negative (-) battery terminal Below 1 Ω
      K141-21 (CA3L) - K141-20 (CAYL) Cable disconnected from negative (-) battery terminal Below 1 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 7 CAN JUNCTION CONNECTOR)

  4. CHECK FOR OPEN IN CAN BUS LINES (NO. 8 CAN JUNCTION CONNECTOR)


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

    2. B003W9WC09
      *a

      Front view of wire harness connector

      (to No. 8 CAN Junction Connector)
      *b to Central Gateway ECU (Network Gateway ECU)

      Disconnect the K116 No. 8 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
      K116-7 (CANH) - K116-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU)
      K116-11 (CANH) - K116-22 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU)
      Result
      Result
      OK
      NG

    OK

    REPLACE NO. 8 CAN JUNCTION CONNECTOR

    NG

  5. CHECK FOR OPEN IN CAN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 8 CAN JUNCTION CONNECTOR)


    1. Reconnect the K116 No. 8 CAN junction connector.

    2. B003X08C21
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

      Disconnect the K141 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
      K141-6 (CA3H) - K141-19 (CAYH) Cable disconnected from negative (-) battery terminal Below 1 Ω
      K141-21 (CA3L) - K141-20 (CAYL) Cable disconnected from negative (-) battery terminal Below 1 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 8 CAN JUNCTION CONNECTOR)