The warning light on the dial comes on (on certain versions together with the message on the display) when dieel fuel filter sensor failure is detected. Contact Fiat Dealership as soon as possible to have the fault removed.
See also:
EOBD system
The EOBD system (European On Board Diagnosis) allows continuos diagnosis of the
components of the car correlated with emissions.
It also alerts the driver, by the turning on of the warning light
...
For checking and restoring pressure only
The compressor can be also used just for restoring pressure. Disconnect the quick
connection and connect it directly to the tyre valve; in this way the cylinder is
not connected to compressor and ...