TC and CG Terminal Circuit [12/2013 - 11/2016]: Description
WARNING: This page is about a different car, the 2016 Toyota Highlander, 2015 Toyota Highlander, and 2014 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
Connecting terminals TC and CG of the DLC3 causes the dynamic radar cruise control system to enter self-diagnostic mode. If a malfunction is present, the cruise control indicator will blink.
HINT:
When a particular warning light remains blinking, a ground short in the wiring of terminal TC of the DLC3 or an internal ground short in the relevant ECU is suspected.