TC and CG Terminal Circuit: Description
WARNING: This page is about a different car, the 2008 Lexus IS F. 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 system to enter self-diagnostic mode If a malfunction is present, the MIL 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