What powers pin 16 (+12V) on OBD port?

I’ve been trying to track down where the OBD port pin 16 gets it’s 12V supply from with no luck.
I’m guessing cars can vary, but it seems like something in mine can momentarily disconnect that supply when the car is off and I’m a bit baffled by it. I don’t know how long it loses power for, could be a fraction of a second but it does seem to happen.

In my specific case, it’s a 2019 Hyundai Accent.

Any ideas?

All cars are different…

Head to Mitchell’s online subscription service and sign up for a subscription just for your Hyundai. Wiring diagrams are available which will show you exactly where that wire comes from.