I can only input what I experienced. My 2000 S4 had one key when I bought it. Now the key/remote/Immobilizer is a 3 piece package. The Key is a metal blank whic may be removed by opening it partially and pushing out the locking pin. The Immobilizer is the FOB half that the ket is attached to. The remote is the other half of the FOB. Thes two are seperated to gain acces to the battery for the remote.
I bought used remotes off Ebay. These are matched/paired to the car in a simple procedure, but you need TWO keys thay will work the ignition and door lock.
Try this, it's from the Bentley:
Programming new remote controls
Two keys and all the remote controls that are to be programmed
will be needed. The maximum number of remote controls that can be
programmed, including old and new, is four.
- Insert first key into ignition switch, and turn it to
- Insert second key into outer door handle, and turn it to
unlocked position for 10 seconds.
System alarm will emit three beeps.
- Take first remote control to be programmed and press button
-1-, two beeps will be emitted. For second remote control, press
button -1-, two beeps will be emitted. Use same procedure to program
third or fourth remote control. All remote controls must be programmed
within one minute, otherwise new programming will cancel and old
remote control programming will be valid.
- Turn key in outer door handle to unlocked position for 10
seconds, one beep will be emitted.
- Switch ignition off.
If your car is an early 2000, it may not have an immobilizer!!! To test push out the pin on you good FOB, leave the FOB 20-30 ft from the car. Now use JUST the metal key to start the car(pliars may be needed to turn it). If it starts...you DO NOT have to have anything done at the dealer.
The key blank may be cut by any locksmith with the proper machine for that style key. If you want, the key may be purchased with the Immobilizer from the dealer. Most states require you to bring the car and registration/title to the dealer or locksmith to verify ownership. I thought my car had the Immobilizer so I bought the key/Immobilizer at the dealer. Cost was about $100 far as I recall. I tried the key to be sure the blank was cut correctly and was surprized when the car started. So I went back inside and told the Service Mgr I didn't need the pairing service and he seemed as surprized as me.