What happened to my key remote?

[Burger]

Last week one of my remotes stopped working - no indications that battery was on its way out - in fact the opposite was working well. Have used the spare since then. Read a few threads where there were rumours of the igntion/contact recoding the key, but this was refuted as it comprimised the security of the key. Well, I just opened the locks with the working key (1st key still not working) placed the dead key into the ignition and started the car. Turned it off and started it again with working key. Then locked and unlocked the car with the problem key - it's now working fine. Any ideas what has happened here?

[andyman]

the key had lost sync with the body control modules 'roling code' system,

what you did is the way to re sync them, alternately you can use the key in the door lock, it will set the alam off when you open the door, but once you put the key in the ignition and turn it on, the alarm will go off

[Burger]

Thanks andyman, thought it must have been something like that but got confused reading previous threads as to what exactly had happened.