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:
14. Electronic Throttle Control (ETC) Light
This light informs you of a problem with the Electronic Throttle Control (ETC)
system. If a problem is detected, the light will come on while the engine is running.
Cycle the ignition key when t ...
24. Door Ajar
This light will turn on to indicate that one or more doors or the trunk may be
ajar. ...
How to warm up the engine after it has just started (petrol and diesel versions)
Proceed as follows:
❒ Drive off slowly, letting the engine turn at medium revs. Do not accelerate
abruptly;
❒ Do not drive at full performance for the initial kilometres. Wait until ...