My 2007 key fob will only work after the car has been driven, say going to the store. When we return to the car the remote will not lock, unlock the doors or the trunk. This is very repeatable. It's as if there were a computer type button battery somewhere in the ECU that has lived its life and needs replacing. Does anyone know if that's the case by chance? We have owned the car since it was one year old and we have two fobs that behave identical to the description.

 

Possibilities:
- Battery on the fobs are weak
- Car battery is weak *Highest Probability*
- You have a loose connection with a wiring harness, driving the car shakes it so it can work again
- You have a corroded connection at a fuse point
- You have two remote fobs that are failing at the same time (not impossible)

I'd start with changing the battery on one of the Fobs and see if that changes performance in comparison to the other, make sure you mark which is which.
I'd also check your vehicle battery with a multi-meter to see what base voltage you're at.
Failing that, check all the fuses with regards to door locks, ECU etc... polish off any corrosion on the fuse spades, there are special files for sprucing up fuse terminals, and that's a relatively cheap fix.