CAN COMMUNICATION SYSTEM Bus Buffer ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Bus Buffer ECU Communication Stop Mode

Any condition is met:


  • Communication stop for "Accessory Gateway" is indicated on the "Communication Bus Check" screen of the GTS.

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  • Communication system DTCs (DTCs that start with U) that correspond to "Bus Buffer ECU Communication Stop Mode" in "DTC Combination Table" are output.

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  • Option connector (bus buffer ECU) branch wire or connector

  • Option connector (bus buffer ECU)

WIRING DIAGRAM

B005ABQE60
*a Dealer-installed Option
*b No. 9 CAN Junction Connector
*c Option Connector (Bus Buffer ECU)

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.

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  • 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.

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  • Some parts must be initialized and set when replacing or removing and installing parts.

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  • 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.

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Tech Tips


  • Operating the engine switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. CHECK FOR OPEN IN CAN BUS WIRE (OPTION CONNECTOR [BUS BUFFER ECU] BRANCH WIRE)


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

    2. B0059P1C06
      *a

      Front view of wire harness connector

      (to Option Connector [Bus Buffer ECU])

      Disconnect the option connector (bus buffer ECU).*

      *: When a dealer-installed option is installed

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I130-4 (CAN+) - I130-8 (CAN-) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Proceed to
      OK
      NG

    OK

    CHECK DEALER-INSTALLED OPTION

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR