Subaru WRX & WRX STI Manuals 2013 Impreza WRX & WRX STI Owner's Manual | Page 344

11-24

Maintenance and service

! Winter (snow) tires
Winter tires are best suited for driving on
snow-covered and icy roads. However
winter tires do not perform as well as
summer tires and all season tires on roads
other than snow-covered and icy roads.

& Tire pressure monitoring
system (TPMS) (if equipped)
The tire pressure monitoring system provides the driver with a warning message
by sending a signal from a sensor that is
installed in each wheel when tire pressure
is severely low. The tire pressure monitoring system will activate only when the
vehicle is driven. Also, this system may
not react immediately to a sudden drop in
tire pressure (for example, a blow-out
caused by running over a sharp object).
If you adjust the tire pressures in a warm
garage and will then drive the vehicle in
cold outside air, the resulting drop in tire
pressures may cause the low tire pressure
warning light to illuminate. To avoid this
problem when adjusting the tire pressures
in a warm garage, inflate the tires to
pressures higher than those shown on the
tire placard. Specifically, inflate them by an
extra 1 psi (6.9 kPa, 0.07 kgf/cm2) for
every difference of 108F (5.68C) between
the temperature in the garage and the

temperature outside. By way of example,
the following table shows the required tire
pressures that correspond to various outside temperatures when the temperature
in the garage is 608F (15.68C).
Example:
Ti r e s i z e : P 2 0 5 / 5 5 R 1 6 8 9 V a n d
P205/50R17 88V
Standard tire pressures:
Front: 33 psi (230 kPa, 2.3 kgf/cm2)
Rear: 32 psi (220 kPa, 2.2 kgf/cm2)
Garage temperature: 608F (15.68C)
Outside
temperature

Adjusted pressure
[psi (kPa, kgf/cm2)]
Front

Rear

308F (−18C)

36 (250, 2.5)

35 (240, 2.4)

108F (−128C)

38
(265, 2.65)

37
(255, 2.55)

−108F (−238C) 40 (280, 2.8)

39 (270, 2.7)

If the low tire pressure warning light
illuminates when you drive the vehicle in
cold outside air after adjusting the tire
pressures in a warm garage, re-adjust the
tire pressures using the method described
above. Then, increase the vehicle speed
to at least 20 mph (32 km/h) and check to
see that the low tire pressure warning light
turns off a few minutes later. If the low tire
pressure warning light does not turn off,

the tire pressure monitoring system may
not be functioning normally. In this event,
go to a SUBARU dealer to have the
system inspected as soon as possible.
While the vehicle is driven, friction between tires and the road surface causes
the tires to warm up. After illumination of
the low tire pressure warning light, any
increase in the tire pressures caused by
an increase in the outside air temperature
or by an increase in the temperature in the
tires can cause the low tire pressure
warning light to turn off.
System resetting is necessary when the
wheels are changed (for example, a
switch to snow tires) and new TPMS
valves are installed on the newly fitted
wheels. Have this work performed by a
SUBARU dealer following wheel replacement.
It may not be possible to install TPMS
valves on certain wheels that are on the
market. Therefore, if you change the
wheels (for example, a switch to snow
tires), use wheels that have the same part
number as the standard-equipment
wheels. Without four operational TPMS
valve/sensors on the wheels, the TPMS
will not fully function and the warning light
on the combination meter will illuminate
steadily after blinking for approximately