...for anyone who needs to add another/ new key to their central locking on the Alfa 156...I've been trying to do this and thought someone in the future might find my experience helpful....
First, I found the previous owner had removed the central locking receiver from under the parcel shelf in the boot. Went and bought a new unprogrammed one off eBay, but I believe any will work - there is no specific programming required to put a 'new' one in the car from a security perspective. Of course, make sure you get one that is the matching frequency for your country and keys. Mine is 433Mhz like europe.
Second, you will need an interface cable to connect to the receiver via the KLL/ OBD. I bought one from diagnostics.co.uk The one I chose allowed switching on the cable rather than adapter cables. Which in this case is very good - as when switched to 12/13 it also connects K line to pin 11 which is where the central locking receiver is located. Other cables might be different so you need to check the internal wiring of the cable.
Third, you will need the right software to program the remote control receiver. The only one I know that works is AlfaOBD. It allows programming of the remote control.
Fourth, the process to add a new remote control key to the car is (once you have the PIN for programming the receiver - I believe these are all the same for Alfa 156 - PM me if you want it):
Login with password, use the "Login with PIN" button on the first tab or 'Login with Password' from active diagnostic list. VAS97 unit does not report if the login is successful or not.
If the PIN is correct it will allow programming, otherwise programming is rejected.
Select "Remote control storage" from Active diagnostic list.
- The ignition key must be in 'STOP'
- The Alarm control unit emergency key must be 'ON' if you have one fitted
Click 'START' and within next 15 seconds activate the remote control for at least 2 seconds. If the program reports "Procedure is not supported" it can mean that the PIN is not accepted.
Click 'Next' to store another code ( and activate next remote for 2 seconds), 'End' to save codes to memory, 'Stop' to abort storage. Do not click 'End' to abort!
Thats it. Mine is a 2 button remote, but I'm seeing if I can add a 3 button remote (from a different Alfa) to the receiver. Will let you know how I go....
Hope this helps someone...