Ram Trucks 2015 Chassis Cab Commercial - Owner Manual - Manual (Page 414)

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 [TPM] Telltale Light) illu-
minates, 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
(25 km/h) in order for the TPMS to receive this informa-
tion.
For example, your vehicle may have a recommended
cold (parked for more than three hours) placard pressure
of 30 psi (207 kPa). If the ambient temperature is 68°F
(20°C) and the measured tire pressure is 27 psi (186 kPa),
a temperature drop to 20°F (-7°C) will decrease the tire
pressure to approximately 23 psi (158 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
27 psi (186 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.
412 STARTING AND OPERATING