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:
Onboard Diagnostic System – OBD II
Your vehicle is equipped with a sophisticated onboard diagnostic system called
OBD II. This system monitors the performance of the emissions, engine, and automatic
transmission control systems. Wh ...
Trip computer
General features
The “Trip computer” displays information (with ignition key at MAR, relating
to the operating status of the vehicle.
This function comprises the “General trip” concerning the comp ...
Installation of electric / electronic devices
Electric/electronic devices installed after buying the car or in aftermarket
shall bear the and marking:
Fiat Auto S.p.A. authorizes the installation of transceivers provided that installation
...