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:
Radio Operation And Mobile Phones
Under certain conditions, the mobile phone being on in your vehicle can cause
erratic or noisy performance from your radio. This condition may be lessened or
eliminated by relocating the mobile ph ...
Changing the battery
If required, replace the battery with a genuine spare part having the same specifications.
If a battery with different specifications is fitted, the service intervals given
in the “Service schedule ...
Cleaning The Rear Park Assist System
Clean the Rear Park Assist sensors with water, car wash soap and a soft cloth.
Do not use rough or hard cloths. In washing stations, clean sensors quickly keeping
the vapor jet/high pressure washi ...