Sorry for reviving an old thread, but it's relevant to my question and I wanted to keep everything in one place for future reference.
Anyway, my dad uses the car most of the time, but we have two keys. He has one and I have one. The one I have is a spare and we got it from those key cutting stores. Both worked perfectly fine.
Then one day he tells me the buttons on his key are deteriorating (I bought replacement buttons before, and so tried to replace them again but this time didn't work), so I gave him my spare and had made another spare for myself.
However, the new spare that I have now works in odd ways - if I want to use it, I can't unlock the car with the buttons. I have to stick the key in the door lock to open the door, which sets off the alarm, and I can only shut it off once I put the key in the ignition. From then on, I can lock/unlock using the buttons.
But after I return the car to my dad, the same problem happens to HIS key now, where he can only unlock it by sticking it in the door, having the alarm go off etc. Now each time we alternate use of the car, we have this problem.
Does anyone know what went wrong or how I can fix this?