SUBARU IMPREZA WRX 2012 4.G Owners Manual

11-20Maintenance and service
Brake booster
If the brake booster does not operate as
described in the following, have it checked
by your SUBARU dealer.
1. With the engine off, depress the brake
pedal several times, applying the same
pedal force each time. The distance the
pedal travels should not vary.
2. With the brake pedal depressed, start
the engine. The pedal should move
slightly down to the floor.
3. With the brake pedal depressed, stop
the engine and keep the pedal depressed
for 30 seconds. The pedal height should
not change.
4. Start the engine again and run for
approximately one minute then turn it off.
Depress the brake pedal several times to
check the brake booster. The brake
booster operates properly if the pedal
stroke decreases with each depression. NOTE
For vehicles equipped with the brake
assist system, when you depress the
brake pedal strongly or suddenly, you
might feel that lighter depression of the
brake pedal generates a greater brak-
ing force. However, even though these
occur, they do not indicate any mal- functions, and the brake assist system
is operating properly.
Brake assist is not a system that brings
more braking ability to the vehicle
beyond its breaking capability.
Brake pedal
Check the brake pedal free play and
reserve distance according to the main-
tenance schedule in the
“Warranty and
Maintenance Booklet ”.
& Checking the brake pedal
free play
1) 0.02 –0.08 in (0.5 –2.0 mm)
Stop the engine and firmly depress the
brake pedal several times. Lightly pull the
brake pedal up with one finger to check
the free play with a force of less than 2 lbf
(10 N, 1 kgf).
If the free play is not within proper
specification, contact your SUBARU deal-
er.

&Checking the brake pedal
reserve distance
1) More than 2.56 in (65 mm)
Depress the pedal with a force of approxi-
mately 66 lbf (294 N, 30 kgf) and measure
the distance between the upper surface of
the pedal pad and the floor.
When the measurement is smaller than
the specification, or when the pedal does
not operate smoothly, contact with your
SUBARU dealer. Clutch pedal
Check the clutch pedal free play and
reserve distance according to the main-
tenance schedule in the
“Warranty and
Maintenance Booklet ”.
& Checking the clutch function
Check the clutch engagement and disen-gagement.
1. With the engine idling, check that there
are no abnormal noises when the clutch
pedal is depressed, and that shifting into
1st or reverse feels smooth.
2. Start the vehicle by releasing the pedal
slowly to check that the engine and
transmission smoothly couple without
any sign of slippage. &
Checking the clutch pedal
free play1) 0.16 –0.43 in (4.0 –11.0 mm)
Lightly depress the clutch pedal down with
your finger until you feel resistance, and
check the free play.
If the free play is not within proper
specification, contact your SUBARU deal-
er. Maintenance and service
11-21

11-22Maintenance and service
Hill start assist system
Ensure that the Hill start assist system
operates properly under the followingcircumstances:
1. Stop the vehicle on an uphill grade by
depressing the brake pedal and clutch
pedal, with the engine running.
2. Make sure that the vehicle does not
move backward even after the brake
pedal is released.
3. Then make sure the vehicle starts
climbing the grade by following the normal
starting procedures.
If the Hill start assist system does not
operate as described above, contact with
your SUBARU dealer. Replacement of brake pad
and lining
The disc brakes have audible wear
indicators on the brake pads. If the brake
pads wear close to their service limit, the
wear indicator makes a very audible
scraping noise when the brake pedal isapplied.
If you hear this scraping noise each time
you apply the brake pedal, have the brake
pads serviced by your SUBARU dealer as
soon as possible.
CAUTION
If you continue to drive despite the
scraping noise from the audible
brake pad wear indicator, it will result in the need for costly brake
rotor repair or replacement.
& Breaking-in of new brake
pads and linings
When replacing the brake pad or lining,
use only genuine SUBARU parts. After
replacement, the new parts must be
broken in as follows. ! Brake pad and lining
While maintaining a speed of 30 to 40
mph (50 to 65 km/h), step on the brake
pedal lightly. Repeat this five or moretimes. ! Parking brake lining
1. Drive the vehicle at a speed of
approximately 22 mph (35 km/h).
2. With the parking brake release button
pushed in, pull the parking brake lever
SLOWLY and GENTLY (pulling with a
force of approximately 33.7 lbf [150 N,
15.3 kgf]).
3. Drive the vehicle for approximately
220 yards (200 meters) in this condition.
4. Wait 5 to 10 minutes for the parking
brake to cool down. Repeat this proce-dure.
5. Check the parking brake stroke. If the
parking brake stroke is out of the specified

range, adjust it by turning the adjusting nut
located on the parking brake lever.Parking brake stroke: 7–8 notches / 45 lbf (200 N, 20.4 kgf)
WARNING
A safe location and situation should
be selected for break-in driving.
CAUTION
Pulling the parking brake lever too
forcefully may cause the rear
wheels to lock. To avoid this, be
certain to pull the lever up slowly
and gently. Parking brake stroke
Check the parking brake stroke according
to the maintenance schedule in the“
Warranty and Maintenance Booklet ”.
When the parking brake is properly
adjusted, braking power is fully applied
by pulling the lever up 7 to 8 notches
gently but firmly (approximately 45 lbf [200
N, 20.4 kgf]). If the parking brake lever
stroke is not within the specified range,
have the brake system checked and
adjusted at your SUBARU dealer. Tires and wheels &
Types of tires
You should be familiar with type of tires
present on your vehicle. ! All season tires
All season tires are designed to provide
an adequate measure of traction, handling
and braking performance in year-round
driving including snowy and icy road
conditions. However all season tires do
not offer as much traction performance as
winter (snow) tires in heavy or loose snow
or on icy roads.
All season tires are identified by “ALL
SEASON ”and/or “M+S ”(Mud & Snow) on
the tire sidewall. ! Summer tires
Summer tires are high-speed capability
tires best suited for highway driving under
dry conditions.
Summer tires are inadequate for driving
on slippery roads such as on snow-
covered or icy roads.
If you drive your vehicle on snow-covered
or icy roads, we strongly recommend the
use of winter (snow) tires.
When installing winter tires, be sure to
replace all four tires. Maintenance and service
11-23
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11-24Maintenance 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 pro-
vides 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 monitor-
ing 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/cm
2) for
every difference of 10 8F (5.6 8C) 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 out-
side temperatures when the temperature
in the garage is 60
8F (15.6 8C).
Example:
Tire size: P205/55R16 89V and
P205/50R17 88V
Standard tire pressures:
Front: 33 psi (230 kPa, 2.3 kgf/cm
2)
Rear: 32 psi (220 kPa, 2.2 kgf/cm2)
Garage temperature: 60 8F (15.6 8C)
Outside
temperature Adjusted pressure
[psi (kPa, kgf/cm
2)]
Front Rear
30 8F( 18C) 36 (250, 2.5) 35 (240, 2.4)
10 8F( 12 8C) 38
(265, 2.65) 37
(255, 2.55)
10 8F( 23 8C) 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 be-
tween 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 replace-ment.
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

one minute.
When a tire is replaced, adjustments are
necessary to ensure continued normal
operation of the tire pressure monitoring
system. As with wheel replacement, there-
fore, you should have the work performed
by a SUBARU dealer.
WARNING
If the low tire pressure warning light
does not illuminate briefly after the
ignition switch is turned ON or the
light illuminates steadily after blink-
ing for approximately one minute,
you should have your Tire Pressure
Monitoring System checked at a
SUBARU dealer as soon as possi-ble.
If this light illuminates while driving,
never brake suddenly and keep
driving straight ahead while gradu-
ally reducing speed. Then slowly
pull off the road to a safe place.
Otherwise an accident involving
serious vehicle damage and serious
personal injury could occur.
If this light still illuminates while
driving after adjusting the tire pres-
sure, a tire may have significant
damage and a fast leak that causes
the tire to lose air rapidly. If you have a flat tire, replace it with a spare tire
as soon as possible.
When a spare tire is mounted or a
wheel rim is replaced without the
original pressure sensor/transmitter
being transferred, the low tire pres-
sure warning light will illuminate
steadily after blinking for approxi-
mately one minute. This indicates
the TPMS is unable to monitor all
four road wheels. Contact your
SUBARU dealer as soon as possible
for tire and sensor replacement and/
or system resetting. If the light
illuminates steadily after blinking
for approximately one minute,
promptly contact a SUBARU dealer
to have the system inspected.
& Tire inspection
Check on a daily basis that the tires are
free from serious damage, nails, and
stones. At the same time, check the tires
for abnormal wear.
Contact your SUBARU dealer immedi-
ately if you find any problem. NOTE . When the wheels and tires strike
curbs or are subjected to harsh treat-
ment as when the vehicle is driven on a rough surface, they can suffer damage
that cannot be seen with the naked eye.
This type of damage does not become
evident until time has passed. Try not
to drive over curbs, potholes or on
other rough surfaces. If doing so is
unavoidable, keep the vehicle
’s speed
down to a walking pace or less, and
approach the curbs as squarely as
possible. Also, make sure the tires are
not pressed against the curb when you
park the vehicle.. If you feel unusual vibration while
driving or find it difficult to steer the
vehicle in a straight line, one of the
tires and/or wheels may be damaged.
Drive slowly to the nearest authorized
SUBARU dealer and have the vehicleinspected.
& Tire pressures and wear
Maintaining the correct tire pressures
helps to maximize the tires ’service lives
and is essential for good running perfor-
mance. Check and, if necessary, adjust
the pressure of each tire (including the
spare) at least once a month (for example,
during a fuel stop) and before any long
journey. Maintenance and service
11-25
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11-26Maintenance and service
Check the tire pressures when the tires
are cold. Use a pressure gauge to adjust
the tire pressures to the values shown on
the tire placard. The tire placard is located
on the door pillar on the driver ’s side.
Driving even a short distance warms up
the tires and increases the tire pressures.
Also, the tire pressures are affected by the
outside temperature. It is best to check tire
pressure outdoors before driving thevehicle.
When a tire becomes warm, the air inside
it expands, causing the tire pressure to
increase. Be careful not to mistakenly
release air from a warm tire to reduce itspressure. NOTE .
The air pressure in a tire increases
by approximately 4.3 psi (30 kPa, 0.3 kgf/cm
2) when the tire becomes warm.
. The tires are considered cold when
the vehicle has been parked for at least
three hours or has been driven less
than one mile (1.6 km).
WARNING
Do not let air out of warm tires to
adjust pressure. Doing so will result
in low tire pressure.
Incorrect tire pressures detract from con-
trollability and ride comfort, and they
cause the tires to wear abnormally. .
Correct tire pressure (tread worn
evenly)
Roadholding is good, and steering is
responsive. Rolling resistance is low, so
fuel consumption is also lower.

.Abnormally low tire pressure (tread
worn at shoulders)
Rolling resistance is high, so fuel con-
sumption is also higher. .
Abnormally high tire pressure (tread
worn in center)Ride comfort is poor. Also, the tire
magnifies the effects of road-surface
bumps and dips, possibly resulting in
vehicle damage.
If the tire placard shows tire pressures for
the vehicle when fully loaded, adjust the
tire pressures to the values that match
current loading conditions.
WARNING
Driving at high speeds with exces-
sively low tire pressures can cause
the tires to deform severely and to
rapidly become hot. A sharp in-
crease in temperature could cause
tread separation, and destruction of the tires. The resulting loss of
vehicle control could lead to anaccident.
& Wheel balance
Each wheel was correctly balanced when
your vehicle was new, but the wheels will
become unbalanced as the tires become
worn during use. Wheel imbalance causes
the steering wheel to vibrate slightly at
certain vehicle speeds and detracts from
the vehicle ’s straight-line stability. It can
also cause steering and suspension sys-
tem problems and abnormal tire wear. If
you suspect that the wheels are not
correctly balanced, have them checked
and adjusted by your SUBARU dealer.
Also have them adjusted after tire repairs
and after tire rotation.
CAUTION
Loss of correct wheel alignment
causes the tires to wear on one side
and reduces the vehicle ’s running
stability. Contact your SUBARU
dealer if you notice abnormal tire
wear. Maintenance and service
11-27
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11-28Maintenance and service
NOTE
The suspension system is designed to
hold each wheel at a certain alignment
(relative to the other wheels and to the
road) for optimum straight-line stability
and cornering performance. &Wear indicators
1) New tread
2) Worn tread
3) Tread wear indicator
Each tire incorporates a tread wear
indicator, which becomes visible when
the depth of the tread grooves decreases
to 0.063 in (1.6 mm). A tire must be
replaced when the tread wear indicator
appears as a solid band across the tread.
WARNING
When a tire ’s tread wear indicator
becomes visible, the tire is worn
beyond the acceptable limit and
must be replaced immediately. With
a tire in this condition, driving at
high speeds in wet weather can
cause the vehicle to hydroplane.
The resulting loss of vehicle control
can lead to an accident.
NOTE
For safety, inspect tire tread regularly
and replace the tires before their tread
wear indicators become visible. &
Tire rotation direction mark
Example of tire rotation direction mark
1) Front
If the tire has the rotation direction
specification, the tire rotation direction
mark is placed on its sidewall.
When you install a tire that has the tire
rotation direction mark, install the tire with
the direction mark facing forward.

&Tire rotation
Vehicles equipped with 4 non-unidirec-
tional tires
1) Front
Vehicles equipped with unidirectional tires
1) Front Tire wear varies from wheel to wheel. To
maximize the life of each tire and ensure
that the tires wear uniformly, it is best to
rotate the tires every 7,500 miles (12,000
km). Move the tires to the positions shown
in the illustration each time they arerotated.
Replace any damaged or unevenly worn
tires at the time of rotation. After tire
rotation, adjust the tires pressures and
make sure the wheel nuts are correctlytightened.
After driving approximately 600 miles
(1,000 km), check the wheel nuts again
and retighten any nut that has becomeloose. &
Tire replacement
The wheels and tires are important and
integral parts of your vehicle ’s design;
they cannot be changed arbitrarily. The
tires fitted as standard equipment are
optimally matched to the characteristics
of the vehicle and were selected to give
the best possible combination of running
performance, ride comfort, and service
life. It is essential for every tire to have a
size and construction matching those
shown on the tire placard and to have a
speed symbol and load index matching
those shown on the tire placard. Using tires of a non-specified size detracts
from controllability, ride comfort, braking
performance, speedometer accuracy and
odometer accuracy. It also creates incor-
rect body-to-tire clearances and inappro-
priately changes the vehicle
’s ground
clearance.
All four tires must be the same in terms of
manufacturer, brand (tread pattern), con-
struction, and size. You are advised to
replace the tires with new ones that are
identical to those fitted as standard equip-ment.
For safe vehicle operation, SUBARU
recommends replacing all four tires at
the same time.
WARNING
. When replacing a tire, you must
use a tire that is of the same size,
circumference, construction,
brand (tread pattern), speed sym-
bol and load index as the original
tires listed on the tire placard.
Using tires of other sizes, cir-
cumferences or constructions
may result in severe mechanical
damage to the drive train of your
vehicle and may affect ride,
handling, braking, speedometer/
odometer calibration, and clear- Maintenance and service
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