Just had the same message appear on my '07 plate Alfa 150 1.9JTD a few weeks back, thought it was just a sensor fault or something then found this thread. Alfa confirmed there is a degredation monitor checking the oil ( why in't this in the manual)
I had assumed my oil had been changed at both my previous services and esp. at 38k mile (2 years) service in June! Evidently not and now I need an oil change for an extra £108!
Not sure if I have made it to 44k miles without a single oil change now! Will need to check my first service record as this was at a different Alfa garage (went bust) to the latest one being used which is Dutton Forshaw Cardiff.