CAN COMMUNICATION SYSTEM(w/o Toyota Safety Sense) Open in One Side of CAN Branch Line

DESCRIPTION

If an ECU or sensor is not displayed on the Communication 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 of one pair of CAN branch lines.

Tech Tips

If some ECUs and sensors repeatedly appear and disappear from the Communication 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 lines. In this case, the CAN branch lines 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 lines).

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

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


  • ECM

  • Brake booster with master cylinder assembly (Skid control ECU)

  • Main body ECU (Multiplex network body ECU)

  • Air conditioning amplifier assembly

  • Power steering ECU assembly

  • Smart key ECU assembly (Certification ECU)*1

  • Airbag sensor assembly

  • Spiral cable with sensor sub-assembly (Steering sensor)

  • Power management control ECU

  • Radio and display receiver assembly*2

  • Combination meter assembly

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.

  • 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 (IG), turn the cruise control system on using the cruise control main switch (ON/OFF switch), wait at least 60 seconds, and then drive the vehicle at a speed of 20 km/h (12 mph) or more.

  • After the repair, perform Communication Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed Click here.

Tech Tips

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 ONE SIDE OF V BUS BRANCH LINE


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

    2. Using the GTS, select and perform the communication bus check Click here.

    3. Observe the screen for approximately 2 minutes to check the ECUs and sensors that are not displayed on the screen and also those that repeatedly appear and disappear from the screen.

    4. Check the applicable communication stop mode for the ECU or sensor that is not displayed on the screen.


    NEXT

    GO TO CORRESPONDING COMMUNICATION STOP MODE Click here