Not what you want to hear but my advice would be to steer well clear of anything to do with module diagnostics on Alfas.
They are so prone to failiure that, even if you succesfully resolve this problem, you will find yourself chasing other faults that 'were ok before you looked at....etc'.
No-one can check/repair the modules. They usually need to be programmed at the dealers and you can never be sure of resolving the fault as there will be another problem lurking around waiting to pop up. Usully about 48hrs after you've handed the car back to the owner.
If you have really got your leg in it is always worth ringing the dealers to see if they sell anything on this particular system with any regularity.
I have used a company called Sherburn Motor Spares (01977 684222) in the past for Alfa problems as they specialise in them (the FOOLS!). They are quite helpful.