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:
Annual inspection schedule
For cars with an annual mileage of below 20,000 km (for example about 15,000
km) the following yearly inspection programme is advised:
❒ check tyre conditions/wear and adjust pressure if req ...
High temperature engine coolant fluid
(red)
Turning the ignition key to MAR the warning light turns on, but it should go
off after few seconds.
The warning light turns on when the engine is overheated.
If the warning light comes on ...
28. Tachometer
The white area of the scale shows the permissible engine revolutions-per-minute
(RPM x 1000) for each gear range.
Before reaching the red area, ease up on the accelerator to prevent engine damage. ...