Check CAN Bus Line: Description
WARNING: This page is about a different car, the 2009 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.
If any DTCs from the CAN communication system are not output, first measure the resistance between the terminals of the DLC3 to specify the trouble area, and check that there is no short in the CAN wire, and +B or GND.