I have an Alfa 2.0 JTS petrol.
The engine warning block and 'go to dealer' comes on. New lambda sensor and soldering/checking/cleaning doesn't seem to help. The fault seems to occur on longer journeys particularly when overtaking say. This seems to be a COMMON ALFA PROBLEM but annoying as it costs to reset the warning system. Quite honestly, I would rather have no sensors or bypass them. They don't seem to serve any useful purpose other than to provide garages with a little earner for resetting them. I can't say I am convinced anybody really knows how to solve this problem effectively.
Oh, by the way, the engine seems to run fine!
So....to any new owner who gets scared to death by this warning ... don't panic!!
Remember the days when cars had none of this extra electronic gadgetry and yourelied on nasty noises, smells, steam or smoke to tell you something was REALLY wrong.
If anyone really does have the definitive answer to the lambda sensor problem I would love to hear from them.