Can Bus Check

HINT: 

The ECUs and sensors that are properly connected to the CAN communication system can be displayed using the Techstream.

1. Using the Techstream, select the CAN Bus Check screen.
   NOTE:

   • It may be possible to select buses that do not have ECUs or sensors from the bus selection pull-down menu. This is not a malfunction. (This occurs when optional devices are not on a sub bus that is monitored by a gateway function equipped ECU.)
   • In the bus selection pull down menu, all buses applicable to the model are displayed (e.g. LIN communication buses are also displayed). Therefore, refer to the wiring diagrams to check the names of sub buses for CAN communication.

     Refer to SYSTEM DIAGRAM [08/2016 - 11/2017]

   HINT: 

   Different connection statuses are indicated by the background color of ECUs and sensors that are displayed.

   EXPLANATION OF CAN BUS CHECK SCREEN
   
   

   Bus Type	Background Color	Connection Status
   V Bus	White	Communication has been normal since the start of the CAN bus check.
   	Yellow	Communication stop occurred at least once since the start of the CAN bus check, but communication is currently occurring (unstable communication).
   	Red	Communication was established at least once since the start of the CAN bus check, but communication is currently not occurring (unstable communication).
   	Not displayed	Communication stop has continued since the start of the CAN bus check.*1
   Sub Bus (gateway function equipped ECU that does not have history of connected ECUs)*2	White	Communication has been normal since the start of the CAN bus check.
   	Yellow	Communication stop occurred at least once since the start of the CAN bus check, but communication is currently occurring (unstable communication).
   	Red	Communication was established at least once since the start of the CAN bus check, but communication is currently not occurring (unstable communication).
   	Not displayed	Communication stop has continued since the start of the CAN bus check.*1
   Sub Bus (gateway function equipped ECU that has history of connected ECUs)*3	White	Communication has been normal since the start of the CAN bus check.
   	Yellow	Communication stop occurred at least once since the start of the CAN bus check, but communication is currently occurring (unstable communication).
   	Red	Currently not communicating (either of the following): Communication stop has continued since the start of the CAN bus check. Communication was established at least once since the start of the CAN bus check, but communication is currently not occurring.
   	Not displayed	Either of the following: If a gateway function equipped ECU cannot communicate, the sub bus and ECUs connected to the sub bus will not be displayed. If no ECUs are connected to the sub bus, "There is no system found on the Communication Bus" will be displayed.

   HINT: 

   • Gateway function equipped ECUs relay signals between the ECUs connected to the different buses.
   • *1: ECUs that are present in the vehicle but are not displayed on the CAN Bus Check screen.
   • *2: Gateway function equipped ECU that does not memorize the sub bus ECUs that are connected to it.
   • *3: Gateway function equipped ECU that memorizes the sub bus ECUs that are connected to it.
   • If none of the connected ECUs are displayed, or there is no response from the vehicle to the Techstream, check the DLC3 branch and the V bus main bus lines for a malfunction.
2. Observe the connection response screen for approximately 2 minutes to check for a change in connection status of the connected ECUs and sensors.

   HINT: 

   • If an open occurs in one of the lines of a CAN branch (except DLC3), output from the other branch line (the line that is not open) will be unstable and it may interfere with the response (display) of other ECUs and sensors.
   • If the connection status changes during the inspection, repair the open in the branch line of the ECU or sensor that does not respond (is not detected) and then perform the CAN bus check again.