Keys: Changed Battery Now Does Not Work

[A3Mike]

Hello,

My wife has a 1.6 A3 (X reg) and recently she noticed that the range of the remote locking/opening had reduced. She decided to change the batteries in the key, and successfully opened it, and put in new replacement batteries.

Now the key does not work at all. She's checked that the batteries are right way in, etc.

Any ideas? Does removing the batteries lose the key settings/codes? If so, how do we go about reprogramming it?

Thanks,

Mike.
(We do have a spare set of keys.)