i'm just curious becuase i did a search and didn't come up with a conclusive answer. what i've been hearing is that the 4.2 A6's all have the immobilizer on them, regardless of year. is there any truth to this? the reason i ask is because i was going to buy another switchblade key off of ebay for a backup, but then saw that post saying that the 4.2 A6's all had the immobilizers, so now i'm not sure whether i'll have to take the key to the dealership to get it programmed so that the immobilizer will still work or if i can just do it with my vagcom. by the way, mine car is a 2000 4.2 quattro sport, if that makes any difference.

 

The first year was 01. to check and see if you have immobilizer. key your car to acc. check to see if you have a key symbol on the dash. if no then you are good to go....That being said there are no 2000 immobilizer A6's 01 was the first year.

 

thanks man, that's def clears everything up for me.

 

And to add to the confusion, some cars, such as mine, came with an immobilizer delete option. Only way to tell is that when you turn on your ignition, if your car is equipped with an immobilizer, then you will see a key symbol on your dash light up for a few seconds, like Baskin4.2l said.