Jeep 2007 Liberty Owner's Manual page 263

The TPM System will warn the driver of a low tire
pressure if the tire pressure falls below the low pressure
warning threshold for any reason, including low tem-
perature effects.
The TPM System 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 recom-
mended cold tire pressure. Once the "Tire Pressure
Monitoring Telltale Light" has been illuminated, the tire
pressure must be increased to the recommended cold tire
pressure in order for the "Tire Pressure Monitoring
Telltale Light" to be turned off. The system will automati-
cally update, and the "Tire Pressure Monitoring Telltale
Light" will extinguish once the updated tire pressures
have been received. The vehicle may need to be driven
for up to 10 minutes above 15 mph (24 km/h) to receive
this information.
STARTING AND OPERATING 263
For example, your vehicle has a recommended cold
(parked for more than 3 hours) tire 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
sufficiently 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 have been
inflated to the vehicle's recommended cold tire pressure
value.
NOTE: Seasonal temperature changes will affect tire
pressure, and the TPM system will monitor the actual tire
pressure in the tire.
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