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.
(b) Observe the connection response screen for approximately 2 minutes to check for a change in connection
status of the connected ECUs and sensors.
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
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.
4. HOW TO INTERPRET CAN BUS CHECK SCREEN
(a) When a communication stop is currently occurring, the probable malfunctioning part can be determined
from the CAN bus check and by using the following methods.
The following CAN bus wiring diagram is provided only as an example. This wiring diagram is different from
the actual wiring diagram for this vehicle.
When a communication stop is currently occurring, it is easier to determine the probable malfunctioning part
from the CAN bus check rather than from communication DTCs.
Wait for approximately 2 minutes after turning the ignition switch to ON (or simulate the driving conditions
that enable the malfunction to be reproduced) and select the CAN bus check. Then observe the
communication status of each ECU on the screen.
(b) If a communication error of only 1 ECU or sensor is indicated on the CAN Bus Check screen, a
communication stop of the ECU or sensor is suspected.
Example: Open in both CAN branch lines of ECU B on the V bus