Fiat 500L 2014 Owner's Manual page 262

260 STARTING AND OPERATING
also increase as the vehicle is driven. This is normal and
there should be no adjustment for this increased pres-
sure.
The TPMS will warn the driver of a low tire pressure if
the tire pressure falls below the low-pressure warning
limit for any reason, including low temperature effects
and natural pressure loss through the tire.
The TPMS will continue to warn the driver of low tire
pressure as long as the condition exists, and will not turn
off until the tire pressure is at or above the recommended
cold placard pressure. Once the low tire pressure warn-
ing (Tire Pressure Monitoring Telltale Light) illuminates,
you must increase the tire pressure to the recommended
cold placard pressure in order for the "Tire Pressure
Monitoring Telltale Light" to turn off. The system will
automatically update and the "Tire Pressure Monitoring
Telltale Light" will turn off once the system receives the
updated tire pressures. The vehicle may need to be
driven for up to 20 minutes above 15 mph (24 km/h) in
order for the TPMS to receive this information.
For example, your vehicle may have a recommended
cold (parked for more than three hours) placard pressure
of 33 psi (227 kPa). If the ambient temperature is 68°F
(20°C) and the measured tire pressure is 28 psi (193 kPa),
a temperature drop to 20°F (-7°C) will decrease the tire
pressure to approximately 24 psi (165 kPa). This tire
pressure is low enough to turn ON the "Tire Pressure
Monitoring Telltale Light." Driving the vehicle may cause
the tire pressure to rise to approximately 28 psi (193 kPa),
but the "Tire Pressure Monitoring Telltale Light" will still
be on. In this situation, the "Tire Pressure Monitoring
Telltale Light" will turn off only after the tires are inflated
to the vehicle's recommended cold placard pressure
value.