I got one of those bluetooth ODB readers and the torque android app would not show any codes even when I get a half engine sign in the car or even the regular code thrown because of the disconnected exhaust flapper.
Procede would show the codes so I don't think regular ODB readers see them.
It might be because the Procede has the canclear which should clear the codes before they get stored as permanent.
I'm certain the shadow codes are even more special so you probably need something like a BT scan tool.
I guess it also depends on how much you paid for your reader