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:
Interiors
Periodically check that water is not trapped under the mats (due to water dripping
off shoes, umbrellas, etc.) which could cause oxidisation of the sheet metal.
CLEANING SEATS AND FABRIC AND VELVET ...
Warning light check function
The instrument panel performs a check on the following warning lights:
❒ handbrake on/low brake fluid level;
❒ ABS and EBD system;
❒ ESP system on/failure;
❒ “Dualdri ...
Windscreen/rear window/headlight washer fluid
To top up, remove the cap (A) and then pour a mixture of water and TUTELA PROFESSIONAL
SC 35, in the following concentrations:
❒ 30% TUTELA PROFESSIONAL SC 35 and 70% water in summer;
...