Have you received any reports of faulty Fiat 500 TwinAir models? My garage says the unit cannot be tested and only replaced at a cost of £611! There's a fault with cylinder two inlet valve sticking open. Other cause of fault could be the ECU. They have spoken to two Fiat dealers, both said they sell at least one of these units per month. I was wondering if it's a design fault. The car is a 2014 model. Not sure how to proceed. Any advice would be appreciated.