This morning when I started my '06 to go to work, I noticed the red battery warning light stayed on. I checked the battery and it's showing a green light (full charge).
The owner's manual indicates that if this light comes on, stop immediately and call your Toyota dealer (whatever) and that it could be the accessory belt. I checked the belt quickly and it seemed fine.
I'm guessing either the belt's slipping or bad alternator? Possibly a bad belt tensioner?