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:
3. Front Fog Light Indicator — If Equipped
This indicator will illuminate when the front fog lights are on. ...
Operation
When the shift lever is in the AutoStick position (to the left of the Drive position),
it can be moved forward and rearward. This allows the driver to manually select
the transmission gear being u ...
Fiat 500 Owners Manual
h1 {color: red;}
h2 {color: green;}
h3 {color: blue;}
h4 {color: #FF00FF;}
...