Originally Posted by jmw748

If you have a spare remote at home, call the house and ask them to find your spare keyfob and keep pressing the unlock button into the phone - they need to keep pressing the remote into the phone receiver.

Put your mobile (receiving call) next to your car lock or where your transponder is and the car will unlock.

Sounds mad, but I was given this tip from a reliable source and it works on both my cars (Audi and wife's Kia Sorento). My wife laughed at me the first time I asked her to test the theory. But she then tried opening her car from the end of the garden behind the house without success, only to find that it did unlock when she "fired" the unlock into her mobile and mine mobile unlocked her car at the front of the house.
May be a bit partial to certain car marques transmission frequencies, but it works for me.

Cra*p solution if you only have one set of keys though or you lock your mobile with your keys in the car!