I bought a 1999 audi a4 with lots of problems. Keys were the least of my problems but, it only came with one and, no key fob. I spent the money and, bought a full version of the ross vag tool. After all mech problems were solved I wanted 2 keys with fobs. With the tool what I found out is that if you had to remotes programmed, you need to either clear the old fobs, or program the new ones into empty spots in the ecu. It will take up to 4 key fobs. The trick is you need to push the unlock button to the space you are programming it for. So, if you had 2 keys programmed before you need to press the unlock button on the key in the drivers door 3 times, 4 times for the fourth key fob. This needs to happen with in 5 secs of turning the key to the unlock position. If you want to clear all key fobs you should push the unlock button 5 times.

 

This is how you program a key, copied right of the manual:Remote Transmitter Coding Procedure
– Switch ignition on (using separate key).
– Check how many transmitters have already been coded in measuring value block 003 Read Measuring Value Block → Chapter.

Indicated on display
Display field 2 indicates how many remote transmitters have been coded and in which memory positions (in the example given, 1 transmitter in position 1).
– Lock vehicle from outside using key to be coded via driver-side door lock.
– Press “unlock” button within 5 seconds often enough to reach next memory position (in example given, twice).
Every press of the button is confirmed by the emergency flashers and the anti-theft system horn.
– Wait 5 seconds.
– Now press “unlock” button one more time (vehicle unlocks).
– Switch ignition off and remove ignition key.
– Check function of new transmitter.
– Check display field 2 in measuring value block 003. It should now display another “1” (in example given: 1100).
NoteBe sure that new transmitters are always coded into free memory positions. If occupied positions (distinguishable by a “1”) are used, the transmitter previously coded to this position will no longer work. THe gist being if you already had 2 remotes programmed to the car you must clear the memory or push the unlock button on the new remote 3 or 4 times to get to a new memory slot where the remote will work

 

I Bought a Audi key programming tools last month, it is quite good to use！
here is the link: BAV BMW VW KEY Programmer Work with Digimaster 3/CKM100 and is not very expensive!
hope is useful to you

 

I just had a local Locksmith in the Minneapolis MN area cut and program a switchblade type key and remote for my1998 A4for $140.00 not cheap but better than the dealer and it only took about 15 minutes after he ordered it in.(Quality Locksmith 651-387-8427 benc@qlsi.biz)