Jeep Wrangler 2020 Owner's Manual page 261

The tire pressure will vary with temperature by approxi-
mately 1 psi (7 kPa) for every 12°F (6.5°C). This means that
when the outside temperature decreases, the tire pressure
will decrease. Tire pressure should always be set based on
cold inflation tire pressure. This is defined as the tire pres-
sure after the vehicle has not been driven for at least three
hours, or driven less than 1 mile (1.6 km) after a three hour
period. The cold tire inflation pressure must not exceed the
maximum inflation pressure molded into the tire sidewall.
Refer to "Tires" in "Servicing And Maintenance" for infor-
mation on how to properly inflate the vehicle's tires. The tire
pressure will also increase as the vehicle is driven. This is
normal and there should be no adjustment for this increased
pressure.
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 pres-
sure 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 warning (Tire
Pressure Monitoring System Warning Light) illuminates,
you must increase the tire pressure to the recommended cold
placard pressure in order for the TPMS Light to turn off.
NOTE:
When filling warm tires, the tire pressure may need to be
increased up to an additional 4 psi (28 kPa) above the recom-
mended cold placard pressure in order to turn the TPMS
Warning Light off.
The system will automatically update and the TPMS
Warning 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
TPMS Warning Light. Driving the vehicle may cause the tire
pressure to rise to approximately 28 psi (193 kPa), but the
TPMS Warning Light will still be on. In this situation, the
TPMS Warning Light will turn off only after the tires are
inflated to the vehicle's recommended cold placard pressure
value.
SAFETY 259
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