FORD 2005 Explorer v.1 - Manual (Page 185)

When inflating your tires
When putting air into your tires (such as at a gas station or in your
garage), the Tire Pressure Monitoring System may not respond
immediately to the air added to your tires. Here are the details:
• The tire pressure monitor sensors mounted in your wheels updates
your vehicle with tire pressure information only once every minute,
therefore it may take up to a minute for the light to turn off after you
have filled your tires to the recommended tire pressure.
• If your vehicle has been parked for over 15 minutes, the sensors go
into a low power mode to conserve battery life and therefore only
transmit about once an hour. If you inflate your tires under these
conditions, the light could take up to an hour to turn off after you
have filled your tires to the recommended tire pressure.
For these reasons, the low tire warning light is NOT a substitute for using
an accurate tire gauge when checking and filling your tires. The best way to
turn off the low tire warning light is to fill your tires to the recommended
tire pressure and drive your vehicle — the tire pressure sensors in your
wheels will update your vehicle with the updated tire pressure when your
vehicle reaches a speed of 20 mph (32 km/h) for at least a minute.
How temperature affects your tire pressure
The Tire Pressure Monitoring System (TPMS) monitors tire pressure in
each pneumatic tire. The pressure in each tire is dependent upon several
factors, one of them being the contained air temperature (temperature of
the air inside the tire). As the contained air temperature increases, the tire
pressure also increases. While driving in a normal manner, a typical
passenger tire inflation pressure may increase approximately 2 to 4 psi (14
to 28 kPa) from a cold start situation. This increase in tire pressure is due
to an increase in the contained air temperature. Contained air temperature
is dependent upon several factors such as rate of tire rotation, tire
deflection, amount of braking, etc. In similar manner, the tire pressure will
decrease if the contained air temperature decreases. For example, if the
vehicle is stationary over night with the outside temperature significantly
lower than the daytime temperature, the tire pressure may decrease
approximately 3 psi (20.7 kPa) for a drop of 30° F (16.6° C) in ambient
temperature. This lower pressure value may be detected by the TPMS as
being significantly lower than the cold pressure indicated on your vehicles
tire label, and activate the TPMS warning for low tire pressure. If the low
warning light is on, visually check each tire to verify that no tire is flat. If
one or more tires are flat, repair as necessary. If all tires appear to be
inflated, carefully drive the vehicle to the nearest location where air can be
added to the tires. Turn the ignition to the “off” position. Inflate all the
tires to the recommended cold pressure.
REVIEW COPY
2005 Explorer (exp), Owners Guide (post-2002-fmt) (own2002),
Market: USA_English (fus)
Tires, Wheels and Loading
185