Hi-I'm a newbie here. I traded my 2005 prius a year and a half ago for an '08 which apparently was a rental car for 40K miles before me. It came with only one key(not a SKS)which recently quit unlocking the doors and hatch remotely. I looked under the steering column and there is only a reset button for the tire sensor guage, and a couple blanks, presumably one would be for the remote/smart key reset. I am currently using the enclosed key to manually unlock the doors. The remote works as usual when I place it in the slot to start the car. I live an hour plus from the closest dealers, and would love to address this issue without having to go there. I checked the FOB battery and even replaced it, although the voltage was practically identical between the existing battery and a new one. The little red light is operational when i press lock/unlock. The car stays outside - i don't have a garage, and remains unlocked between trips. Recently it sat for several days in the last large snowstorm. When I finally drove it up the 1/3 mile driveway, it would not lock when i was ready to leave it up on the 'hard road'. I've checked out a few related threads, but haven't hit on this issue yet. Perhaps the 12V battery is weak?