2.2 JTS Timing Chain
My 2.2 JTS Spider had the timing chain replaced under warranty after 12,000 miles and it has just been done again a 62,000 miles. The ECU light has come back on but as the old chain was very slack when it came off, I'm pretty sure that replacing the solenoid will cure it completely.
Unfortunately this is a well documented problem with this engine, not only in the Alfa but also in the Vauxhall Vectra from where AR nicked the engine.
The main dealer will quote anything between £1,200 and £1,400 to do the chain but find a good indy Alfa specialist and you should get it done for somewhere south of £700.
Lewis at Alfatecnico just off J28 M1 who did mine this time confirmed that the chains are only good for 40,000 to 60,000 miles, although increasing the oil change frequency will help.
As this is a Vauxhall engine it's reasonable to assume that the "genuine" Alfa parts are sourced from Vauxhall, but they are twice the price of the equivalent Vauxhall parts.