You definitely don’t want to spend extra money on a trip to the mechanic if you could easily solve the problem on your own. An OBD-II scanner will help—but first, you need to know where to put it!
The OBD port is a long, 16-prong outlet, and you’ll probably need to use a flashlight to make it easier to find. Unfortunately, you may be better off going to a mechanic if the OBD port in your 2012 Camry is hidden behind interior paneling, as they’ll be better equipped to remove the paneling without damaging it.