+1 GSDOUBLEU .
What to do to see what your sitch is: Check your key fob. If there is a battery hatch on the back, it is a "Comfort Access" or "Convenient Access" key fob. If not, stop here, you don't have the feature.
If it IS a CA fob, then it must be coded to your car. I changed the battery on my two fobs (yes it is CR2032 - about the size of a quarter) and one of mine worked for CA, the other did not.
If it IS a CA fob and does NOT work with a fresh battery, it must be coded to your car by your dealership, and will likely cost you 0.5 hours at your local shop rate. The car can apparently only handle TWO fob codes. If one of the fobs has ever been replaced, the new fob needs to be coded overtop of the old one.