I would remove pandora and try loading maps again. If that does not work a wipe and reinstall of your phone. Back up 1st... when you getting it working try reinstalling pandora maybe something was corrupt...
Ironically and semi-unrelated to your problem, I had Pandora and some huge battery issues. When I deleted Pandora, my battery issues have all been resolved. Maybe a fluke, but maybe it will help you to know that too- just wanted to share.