Turning the key to MAR the warning light on the dial turns on, but it should go off as soon as the engine is started.
If the 
warning light turns on when
the car is travelling (on certain versions together with the message on the display),
stop the engine immediately and contact a Fiat Dealership.
See also:
Windscreen/rear window washer fluid
To top up, remove the cap A-fig. 12 and lift the telescopic filler B, until it
clicks.
Pour a mixture of water and TUTELA PROFESSIONAL SC 35, in the following concentrations:
30% of TUTELA PROFESS ...
Sunroof
It is controlled electrically and it will only work when the ignition key is
at MAR.
Sunroof is controlled by a switch. When you release it the roof locks in the
position it is at that moment.
...
Ignition Key Removal
1. Place the shift lever in PARK (if equipped with an automatic transmission).
2. Turn the ignition switch to the ACC/ON/RUN position.
3. Rotate the key to the OFF/LOCK position.
4. Remove the key ...