I know this subject has been covered a lot and most of the threads on new keys and immobilisers get a little of track and confusing. There are several types of immobilisers used on Alfas this one is for 156 and 166 models up to 2002 Code 2 only.
I know a few of you have cars that at some point have had there ECU's and lock sets changed then run into problems getting new keys cut later as the details for your code card held buy Alfa no longer match your vehicle I know this wont help all of you but it is possible to retrieve your code from the immobiliser and have new immobiliser chips made without having to go through the dealer.
All the data relating to your keys and your pin code is held in a small file on an eprom chip in the immobiliser box. Reading this type of chip is actually very easy with some basic equipment. Although this is as much as you can do buy yourself without some serious investment.
If its something you feel comfortable doing I'll happily extract your pin from the file for you. This file can also be used to produce new immobiliser chips for your car. Although you can't really do this yourself if you have the file already you should find plenty of locksmiths capable of programming the chip for you at a much more reasonable price than the dealer or if you had a locksmith do it for you from scratch.
This is the code box and keys in question.
The information relating to the keys and code is held in the little 8 legged chip you can see in the middle of the last picture. The chip is a 93c56 eprom which is a relativley basic memory chip. You can get programmers that will read these chips for under £20 on ebay. http://cgi.ebay.co.uk/ws/eBayISAPI.d...#ht_946wt_1093
If your not comfortable soldering this sort of thing which I'm guessing most of you wont be you will need a test clip (soic8/sop8) http://cgi.ebay.co.uk/3M-SOIC-SOP-8-...#ht_4156wt_862
as well so you can read the chip without removing it. If you want to read it in circuit you must short the quartz which is the silver oval component next to the chip. The legs of the chip protrude through the base of the circuit board so you can do this by simply pressing them against a bit of conductive metal whilst reading the chip a nice clean penny works fine.
Once you have done this you should end up with a file that looks like this.
This is about as far as you can go without investing some more serious cash in software and equipment. If you want your pin then send me your file and I'll extract it for you. If you want a new immobiliser chip then give the file to your local auto locksmith and they should be able to make one for you. If you don't have any one local then it can be done by post.
Once you have your immo chip it will be ready to start the car all you need to do from there is put it into a standard key and have it cut or a new or second hand remote with a new key blade. The remote can then be programmed either by the dealer or you can do it on alfa obd if you have it. The code for the remote is different to the one for the immobiliser and you will need to get this from the dealer if possible.