CAN COMMUNICATION SYSTEM(w/o Central Gateway ECU) Open in One Side of CAN Branch Line

DESCRIPTION

If an ECU or sensor is not displayed on the "CAN Bus Check" screen of the GTS and some ECUs and sensors repeatedly appear and disappear from the screen when the CAN main bus lines are normal (there is no open, short, short to +B or short to GND in the main bus lines), there may be an open circuit in either wire of one pair of CAN branch wires.

Tech Tips

If some ECUs and sensors repeatedly appear and disappear from the "CAN Bus Check" screen, communication between the normal ECUs (sensors) and the GTS may be affected by the incomplete signals that are output from the ECU that has an open circuit in either of its CAN branch wires. In this case, the CAN branch wires for the ECUs and sensors that repeatedly appear and disappear from the screen are normal and the ECU that is not displayed on the screen may be the main cause of the problem (this ECU may have an open circuit in either of its CAN branch wires).

Symptom Trouble Area
2 or more ECUs and/or sensors do not appear on the GTS "CAN Bus Check" screen.

One side of CAN branch wire is open, or output signals are incomplete.


  • Brake actuator assembly (skid cotrol ECU)

  • 4 wheel drive control ECU

  • Airbag sensor assembly

  • Air conditioning amplifier assembly

  • Main body ECU (multiplex network body 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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  • 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.

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

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PROCEDURE


  1. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE


    1. Based on the vehicle equipment and specifications, confirm the systems that use CAN communication.

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    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the GTS on.

    5. Using the GTS, perform "CAN Bus Check".

      Click here

    6. Observe the screen for approximately 2 minutes to check for ECUs and sensors that are displayed as not communicating.

    7. Perform the inspection as specified in the Problem Symptoms Table for the ECUs or sensors that are not communicating.

      Result
      Proceed to
      NEXT

    NEXT

    GO TO CORRESPONDING COMMUNICATION STOP MODE Click here