engine SUBARU IMPREZA WRX STI 2012 Repair Manual

Black plate (266,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
7-16
Starting and operating
& Driving tipsDo not drive with your foot resting on the
clutch pedal and do not use the clutch to
hold your vehicle at a standstill on an
upgrade. Either of those actions may
cause clutch damage.
Do not drive with your hand resting on the
shift lever. This may cause wear on the
transmission components.
When it is necessary to reduce vehicle
speed due to slow traffic, turning corners,
or driving up steep hills, downshift to a
lower gear before the engine starts to
labor.
On steep downgrades, downshift the
transmission to 5th, 4th, 3rd or 2nd gear
as necessary; this helps to maintain a safe
speed and to extend brake pad life.
In this way, the engine provides a braking
effect. Remember, if you “ride”(over use)
the brakes while descending a hill, they
may overheat and not work properly.
The engine may, on rare occasions, knock
when the vehicle rapidly accelerates or
rapidly pulls away from a standstill. This
phenomenon does not indicate a malfunc-
tion.
Manual transmission –5
speeds (except STI)The manual transmission is a fully syn-
chromeshed, 5-forward-speed and 1-re-
verse-speed transmission.
The shift pattern is shown on the shift
lever knob. When shifting from 5th gear to
reverse gear, first return the shift lever to
the neutral position then shift into reverse
gear.
To change gears, fully depress the clutch
pedal, move the shift lever, and gradually
let up on the clutch pedal.
If it is difficult to shift into gear, put the
transmission in neutral, release the clutch
pedal momentarily, and then try again.
WARNING
. Do not drive the vehicle with the
clutch disengaged (i.e., when the
clutch pedal is depressed) or
with the shift lever in the neutral
position. Engine braking has no
effect in either of these condi-
tions and the risk of an accident
is consequently increased.
. Do not engage the clutch (i.e.,
release the clutch pedal) sud-
denly when starting the vehicle.
By doing so the vehicle might
unexpectedly accelerate or the
transmission could malfunction.
CAUTION
Shift into reverse ONLY when the
vehicle has completely stopped. It
may cause damage to the transmis-
sion to try shifting into reverse when
the vehicle is moving.

Black plate (267,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
& Shifting speeds! Recommended shifting speeds
The best compromise between fuel econ-
omy and vehicle performance during
normal driving is ensured by shifting up
at the speeds listed in the following table.
Shift up mph (km/h)
1st to 2nd 15 (24)
2nd to 3rd 25 (40)
3rd to 4th 40 (64)
4th to 5th 45 (72)
!
Maximum allowable speeds
The following table shows the maximum
speeds that are possible with each differ-
ent gear. The tachometer ’s needle will
enter the red area if these speeds are
exceeded.
With the exception of cases where sudden
acceleration is required, the vehicle
should not be driven with the tachometer ’s
needle inside the red area. Failure to
observe this precaution can lead to
excessive engine wear and poor fuel
economy.
mph (km/h)
1st 37 (61)
2nd 64 (104)
WARNING
When shifting down a gear, ensure
that the vehicle is not travelling at a
speed exceeding the Maximum Al-
lowable Speed for the gear which is
about to be selected. Failure to
observe this precaution can lead to
engine over-revving and this in turn
can result in engine damage.
In addition, sudden application of
engine brakes when the vehicle is
travelling on a slippery surface can
lead to wheel locking; as a conse-
quence, control of the vehicle may
be lost and the risk of an accident
increased.NOTENever exceed the posted speed limit.&
Driving tipsDo not drive with your foot resting on the
clutch pedal and do not use the clutch to
hold your vehicle at a standstill on an
upgrade. Either of those actions may
cause clutch damage. Do not drive with your hand resting on the
shift lever. This may cause wear on the
transmission components.
When it is necessary to reduce vehicle
speed due to slow traffic, turning corners,
or driving up steep hills, downshift to a
lower gear before the engine starts to
labor.
On steep downgrades, downshift the
transmission to 4th, 3rd or 2nd gear as
necessary; this helps to maintain a safe
speed and to extend brake pad life.
In this way, the engine provides a braking
effect. Remember, if you
“ride”(over use)
the brakes while descending a hill, they
may overheat and not work properly.
The engine may, on rare occasions, knock
when the vehicle rapidly accelerates or
rapidly pulls away from a standstill. This
phenomenon is not an indication of a
problem in your vehicle.
Starting and operating
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Black plate (272,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
7-22
Starting and operating
SI-DRIVE (STI)SI-DRIVE (SUBARU Intelligent Drive)
works to maximize engine performance,
control and efficiency.
This system consists of three modes:
Intelligent (I), Sport (S), and Sport Sharp
(S#). By adjusting the SI-DRIVE selector,
the character of the power unit changes.& Intelligent (I) mode! For smooth, efficient performance
drivingThe Intelligent (I) mode provides well-
balanced performance with greater fuel
efficiency and smooth driveability without
stress. Power delivery is moderate during
acceleration for maximum fuel efficiency. This is ideal for around-town driving and
situations that do not require full power
output. It provides better control in difficult
driving conditions, such as slippery roads
or loose surfaces, due to gentler throttle
response.
When Intelligent (I) mode is selected, a
shift-up indicator
“
”on the combination
meter will blink to signal the best time to
shift gears for maximum fuel efficiency.
& Sport (S) mode! For all-around performance drivingThe Sport (S) mode provides the engine
power desired by those who want to make
the driving experience their own personal
adventure.
The linear acceleration characteristic of
this versatile mode is ideal for normal
driving use.

Black plate (273,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
& Sport Sharp (S#) mode! For maximum performance drivingFor sports-minded drivers, the Sport
Sharp (S#) mode offers an exhilarating
level of engine performance and control.
The throttle becomes more responsive
regardless of the engine speed. Delivering
maximum driving enjoyment, this mode is
ideal for tackling twisting roads and for
merging or overtaking other vehicles on
the freeway with confidence.
&SI-DRIVE selectorWhen you rotate the SI-DRIVE selector to
the left, the current SI-DRIVE mode
changes to Sport (S) mode. When you
rotate it to the right, the mode changes to
Sport Sharp (S#) mode, and when you
push it, the mode changes to Intelligent (I)
mode. After performing this operation, the
switch returns to its original location.NOTE. The next time you turn on the
engine, after you turned off the engine
in the Sport Sharp (S#) mode, the SI-
DRIVE mode changes to the Sport (S)
mode.
. The next time you turn on the
engine, after you turned off the engine
in the Sport (S) mode or Intelligent (I)
mode, the SI-DRIVE mode will stay in the same mode as when the engine
was turned off.
.
While the engine is running, if the
CHECK ENGINE warning light/malfunc-
tion indicator light illuminates, the SI-
DRIVE mode changes to the Sport (S)
mode. In this case, it is not possible to
change to the Sport Sharp (S#) mode or
Intelligent (I) mode.
. If there is a possibility that the
engine could overheat because of a
temperature increase of the engine
coolant, it is not possible to change to
the Sport Sharp (S#) mode. While the
vehicle is in the Sport Sharp (S#) mode,
it changes to the Sport (S) mode when
the engine coolant temperature in-
creases.
. If any of the SI-DRIVE indicators
blink, the SI-DRIVE system may be
malfunctioning. Contact your SUBARU
dealer.
Starting and operating
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Black plate (274,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
7-24
Starting and operating
Limited slip differential (LSD)
(STI)The LSD provides optimum distribution of
power according to the difference in
revolutions between the right and left
wheels that may be caused by certain
driving conditions, thereby improving driv-
ing stability on snow-covered, muddy or
other slippery roads or when high speed
driving.
CAUTION
. Never start the engine while a tire
on one side is jacked up, as the
vehicle may move.
. If one tire is spinning in mud,
avoid continued spinning at high
speed as this could adversely
affect the LSD.
. If you use a temporary spare tire
to replace a flat tire, be sure to
use the original temporary spare
tire stored in the vehicle. Using
other sizes will adversely affect
the LSD.
Power steeringThe power steering system operates only
when the engine is running.
If you lose power steering assist because
the engine stops or the system fails to
function, you can steer but it will take
much more effort.
CAUTION
Do not hold the steering wheel at the
fully locked position left or right for
more than 5 seconds. This may
damage the power steering pump.NOTERight after the engine has been started
and before it has warmed up, you may
hear a noise coming from areas adja-
cent to the power steering pump which
is located at the right-front area of the
engine compartment. This noise is
normal. It does not indicate power
steering system trouble.
Braking& Braking tips
WARNING
Never rest your foot on the brake
pedal while driving. This can cause
dangerous overheating of the
brakes and needless wear on the
brake pads and linings.
! When the brakes get wet
When driving in rain or after washing the
vehicle, the brakes may get wet. As a
result, brake stopping distance will be
longer. To dry the brakes, drive the vehicle
at a safe speed while lightly depressing
the brake pedal to heat up the brakes.
! Use of engine braking
Remember to make use of engine braking
in addition to foot braking. When descend-
ing a grade, if only the foot brake is used,
the brakes may start working improperly
because of brake fluid overheating,
caused by overheated brake pads. To
help prevent this, shift into a lower gear to
get stronger engine braking.
! Braking when a tire is punctured
Do not depress the brake pedal suddenly
when a tire is punctured. This could cause

Black plate (275,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
a loss of control of the vehicle. Keep
driving straight ahead while gradually
reducing speed. Then slowly pull off the
road to a safe place.& Brake system! Two separate circuits
Your vehicle has two separate circuit
brake systems. Each circuit works diag-
onally across the vehicle. If one circuit of
the brake system should fail, the other half
of the system still works. If one circuit fails,
the brake pedal will go down much closer
to the floor than usual and you will need to
press it down much harder. And a much
longer distance will be needed to stop the
vehicle.
! Brake booster
The brake booster uses engine manifold
vacuum to assist braking force. Do not
turn off the engine while driving because
that will turn off the brake booster, result-
ing in poor braking power.
The brakes will continue to work even
when the brake booster completely stops
functioning. If this happens, however, you
will have to depress the pedal much
harder than normal and the braking dis-
tance will increase. !
Brake assist system
WARNING
Do not be overconfident about the
brake assist. It is not a system that
brings more braking ability to the
vehicle beyond its braking capabil-
ity. Always use the utmost care
when driving regarding vehicle
speed and safe distance.
CAUTION
When you need to brake suddenly,
continue depressing the brake pedal
strongly to bring the effect of the
brake assist.
Brake assist is a driver assistance system.
It assists the brake power when the driver
cannot depress the brake pedal strongly
and the brake power is insufficient.
Brake assist generates the brake power
according to the speed at which the driver
depresses the brake pedal.NOTEWhen you depress the brake pedal
strongly or suddenly, the following
phenomena occur. However, even
though these occur, they do not indi- cate any malfunctions, and the brake
assist system is operating properly.
.
You might feel that the brake pedal
is applied by lighter force and gener-
ates a greater braking force.
. You might hear the sound of ABS
operating from the engine compart-
ment.
& Disc brake pad wear warning
indicatorsThe disc brake pad wear warning indica-
tors on the disc brakes give a warning
noise when the brake pads are worn.
If a squeaking or scraping noise is heard
from the disc brakes while braking, im-
mediately have your vehicle checked by
your SUBARU dealer.
Starting and operating
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Black plate (276,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
7-26
Starting and operating
ABS (Anti-lock Brake Sys-
tem)The ABS system prevents the lock-up of
wheels which may occur during sudden
braking or braking on slippery road sur-
faces. This helps prevent the loss of
steering control and directional stability
caused by wheel lock-up.
When the ABS system is operating, you
may hear a chattering noise or feel a slight
vibration in the brake pedal. This is normal
when the ABS operates.
The ABS system will not operate when the
vehicle speed is below approximately 6
mph (10 km/h).
WARNING
Always use the utmost care in
driving –overconfidence because
youaredrivingwithanABS
equipped vehicle could easily lead
to a serious accident.
CAUTION
. The ABS system does not always
decrease stopping distance. You
should always maintain a safe
following distance from other vehicles.
. When driving on badly surfaced
roads, gravel roads, icy roads, or
over deep newly fallen snow,
stopping distances may be long-
er for a vehicle with the ABS
system than one without. When
driving under these conditions,
therefore, reduce your speed and
leave ample distance from other
vehicles.
. When you feel the ABS system
operating, you should maintain
constant brake pedal pressure.
Do not pump the brake pedal
since doing so may defeat the
operation of the ABS system.
& ABS system self-checkJust after the vehicle is started, you may
feel on the brake pedal a vibration similar
to when the ABS operates, and you may
also hear the sound of the ABS working
from the engine compartment. This is
caused by an automatic functional test of
the ABS system being carried out and
does not indicate any abnormal condition.&ABS warning lightRefer to “ABS warning light ”F 3-18.
Electronic Brake Force Dis-
tribution (EBD) systemThe EBD system maximizes the effective-
ness of the brakes by allowing the rear
brakes to supply a greater proportion of
the braking force. It functions by adjusting
the distribution of braking force to the rear
wheels in accordance with the vehicle’ s
loading condition and speed.
The EBD system is an integral part of the
ABS system and uses some of the ABS
system ’s components to perform its func-
tion of optimizing the distribution of brak-
ing force. If any of the ABS components
used by the EBD system malfunction, the
EBD system also stops working.
When the EBD system is operating, you
may hear a chattering noise or feel a slight
vibration in the brake pedal. This is normal
and does not indicate a malfunction.

Black plate (277,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
& Steps to take if EBD system
malfunctionsIf a malfunction occurs in the EBD system,
the system stops working and the brake
system warning light and ABS warning
light illuminate simultaneously.
The EBD system may be malfunctioning if
the brake system warning light and ABS
warning light illuminate simultaneously
during driving.
Even if the EBD system malfunctions, the
conventional braking system will still func-
tion. However, the rear wheels will be
more prone to locking when the brakes
are applied harder than usual and the
vehicle’ s motion may therefore become
somewhat harder to control.
If the brake system warning light and ABS warning light illuminate simultaneously,
take the following steps.
1. Stop the vehicle in the nearest safe,
flat location.
2. Shut down the engine, apply the
parking brake, and then restart it.
3. Release the parking brake. If both
warning lights turn off, the EBD system
may be malfunctioning. Drive carefully to
the nearest SUBARU dealer and have the
system inspected.
4. If both warning lights illuminate again
and remain illuminated after the engine
has been restarted, shut down the engine
again, apply the parking brake, and check
the brake fluid level. Refer to
“Brake fluid”
F 11-18.
5. If the brake fluid level is not below the
“MIN ”mark, the EBD system may be
malfunctioning. Drive carefully to the
nearest SUBARU dealer and have the
system inspected.
6. If the brake fluid level is below the
“MIN ”mark, DO NOT drive the vehicle.
Instead, have the vehicle towed to the
nearest SUBARU dealer for repair.
WARNING
. Driving with the brake system
warning light illuminated is dan- gerous. This indicates your brake
system may not be working
properly. If the light remains
illuminated, have the brakes in-
spected by a SUBARU dealer
immediately.
. If at all in doubt about whether
the brakes are operating prop-
erly, do not drive the vehicle.
Have your vehicle towed to the
nearest SUBARU dealer for re-
pair.
Starting and operating
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Black plate (278,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
7-28
Starting and operating
Vehicle Dynamics Control
system
WARNING
Always use the utmost care in
driving –overconfidence because
you are driving with a Vehicle Dy-
namics Control system equipped
vehicle could easily lead to a ser-
ious accident.
CAUTION
. Even if your vehicle is equipped
with Vehicle Dynamics Control
system, winter tires should be
used when driving on snow-cov-
ered or icy roads; in addition,
vehicle speed should be reduced
considerably. Simply having a
Vehicle Dynamics Control sys-
tem does not guarantee that the
vehicle will be able to avoid
accidents in any situation.
. Activation of the Vehicle Dy-
namics Control system is an
indication that the road being
travelled on has a slippery sur-
face; since having Vehicle Dy-
namics Control is no guarantee that full vehicle control will be
maintained at all times and under
all conditions, its activation
should be seen as a sign that
the speed of the vehicle should
be reduced considerably.
. Whenever suspension compo-
nents, steering components, or
an axle are removed from a
vehicle, have an inspection of
that system performed by an
authorized SUBARU dealer.
. The following precautions should
be observed in order to ensure
that the Vehicle Dynamics Con-
trol system is operating properly:
– All four wheels should be
fitted with tires of the same
size, type, and brand. Further-
more, the amount of wear
should be the same for all
four tires.
– Keep the tire pressure at the
proper level as shown on the
vehicle placard attached to
the driver ’s side door pillar.
– Use only the specified tem-
porary spare tire to replace a
flat tire. With a temporary
spare tire, the effectiveness
of the Vehicle Dynamics Con- trol system is reduced and
this should be taken into ac-
count when driving the vehi-
cle in such a condition.
. If non-matching tires are used,
the Vehicle Dynamics Control
system may not operate cor-
rectly.
. The Vehicle Dynamics Control
system helps prevent unstable
vehicle motion such as skidding
using control of the brakes and
engine power. Do not turn off the
Vehicle Dynamics Control sys-
tem unless it is absolutely ne-
cessary. If you must turn off the
Vehicle Dynamics Control sys-
tem, drive very carefully based
on the road surface condition.
In the event of wheelspin and/or skidding
on a slippery road surface and/or during
cornering and/or an evasive maneuver,
the Vehicle Dynamics Control system
adjusts the engine ’s output and the
wheels ’respective braking forces to help
maintain traction and directional control.
. Traction Control Function
The traction control function is designed to
prevent spinning of the driving wheels on
slippery road surfaces, thereby helping to
maintain traction and directional control.

Black plate (279,1)
北米Model "A1130BE-A" EDITED: 2011/ 6/ 7
Activation of this function is indicated by
steady illumination of the Vehicle Dy-
namics Control operation indicator light.
. Skid Suppression Function
The skid suppression function is designed
to help maintain directional stability by
suppressing the wheels ’tendency to slide
sideways during steering operations. Acti-
vation of this function is indicated by
flashing of the Vehicle Dynamics Control
operation indicator light.NOTE. The Vehicle Dynamics Control sys-
tem may be considered normal when
the following conditions occur.
–Slight twitching of the brake
pedal is felt.
– The vehicle or steering wheel
shakes to a small degree.
– An operating sound from the
engine compartment is heard
briefly when starting the engine
and when driving off after starting
the engine.
– The brake pedal seems to jolt
when driving off after starting the
engine.
. In the following circumstances, the
vehicle may be less stable than it feels
to the driver. The Vehicle Dynamics Control System may therefore operate.
Such operation does not indicate a
system malfunction.
–on gravel-covered or rutted
roads
– on unfinished roads
– when the vehicle is fitted with
snow tires or winter tires
. Activation of the Vehicle Dynamics
Control system will cause operation of
the steering wheel to feel slightly
different compared to that for normal
conditions.
. It is always important to reduce
speed when appro aching a corner,
even if the vehicle is equipped with
Vehicle Dynamics Control.
. Always turn off the engine before
replacing a tire as failure to do so may
render the Vehicle Dynamics Control
system unable to operate correctly.
& Vehicle Dynamics Control
system monitorRefer to “Vehicle Dynamics Control warn-
ing light/Vehicle Dynamics Control opera-
tion indicator light ”F 3-20 and “Vehicle
Dynamics Control OFF indicator light/
Traction Control OFF indicator light (STI) ”
F 3-21.
& Vehicle Dynamics Control
mode switch (STI)Indicator lightVehicle Dynamics Control mode switchWhen the switch is pressed briefly or for
more than approximately 3 seconds dur-
Starting and operating
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