Well, I figured out what the "problem" was! Apparently the 2011+ models come with an "Extended Storage Switch" in that fuse box by the dead pedal. It comes from the factory in the 'off' position. Apparently the dealer is supposed to switch it to 'on' before they sell the car.
I pushed in the switch until it clicked, and sure enough, the OBDII scanner turned right on!
More info on the "Extended Storage Switch" can be found in this thread:
http://www.the370z.com/exterior-inte...ge-switch.html
Here's an image of the switch (snagged it from the thread I linked above):
