2011 SUBARU IMPREZA engine

Power steering
The 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.
NOTE
Right 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 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 thevehicle. ! 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. Starting and operating
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7-32Starting and operating
!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. NOTE
When 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 indicators
The 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. 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
you are driving with an ABS
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 othervehicles.
. 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-check
Just 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 light
Refer to “ABS warning light ”F 3-21. Electronic Brake Force Dis-
tribution (EBD) system
The 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 ABSsystem ’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. &
Steps to take if EBD system malfunctions
Turbo models
Non-turbo models
If a malfunction occurs in the EBD system,
the system stops working and the brake Starting and operating
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7-34Starting and operating
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 thevehicle’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 11-25. 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. 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. 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 circumstances listed in the
following, the vehicle may be more
unstable than it feels to the driver. Starting and operating
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7-36Starting and operating
The Vehicle Dynamics Control System
may therefore operate. Such operation
does not indicate a system malfunc-tion. –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 normalconditions. . It is always important to reduce
speed when approaching 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 monitor
Refer to “Vehicle Dynamics Control opera-
tion indicator light ”F 3-23 and “Vehicle
Dynamics Control warning light/Vehicle
Dynamics Control OFF indicator light/
Traction Control OFF indicator light (STI) ”
F 3-23. &
Vehicle Dynamics Control
mode switch (STI)
Indicator light
Vehicle Dynamics Control mode switch
When the switch is pressed briefly or for
more than approximately 3 seconds dur- ing engine operation, the mode of the
Vehicle Dynamics Control System will bechanged. !
Vehicle Dynamics Control mode
When the ignition switch is on, this mode
is selected.
This mode enables all controls for ABS,
the Traction Control System, and the
Vehicle Dynamics Control system. Select
this mode for most driving situations.
When this mode is selected, the indicator
light on the combination meter turns off. ! Traction mode
This mode restricts the functions of the
Traction Control System and Vehicle
Dynamics Control system and thus delays
utilizing their functions as a reaction to
vehicle behavior in comparison with the
Vehicle Dynamics Control mode. This
mode should be used in driving situations
where the vehicle dynamic performance
will improve without decreasing engine
torque control.
When the switch is pressed briefly during
engine operation, the indicator light on the
combination meter illuminates in green.
When the switch is pressed again to
reactivate the Vehicle Dynamics Control
system, the indicator light turns off.

!Vehicle Dynamics Control OFF mode
This mode allows only the ABS control.
This mode should be used in an emer-
gency situation such as getting out of
snow or mud.
When the switch is pressed for more than
approximately 3 seconds during engine
operation, the indicator light on the com-
bination meter illuminates in yellow. When
the switch is pressed again to reactivate
the Vehicle Dynamics Control system, the
indicator light turns off. NOTE . The Vehicle Dynamics Control sys-
tem will be activated automatically
when the engine is started.. If the switch is held down for 10
seconds or longer, the indicator light
turns off, the Vehicle Dynamics Control
system is activated, and the system
ignores any further pressing of the
switch. To make the switch usable
again, turn the ignition switch to the“ LOCK ”position and restart the en-
gine.. When the Vehicle Dynamics Control
OFF mode is selected, the vehicle ’s
running performance is comparable
with that of a vehicle that does not
have a Vehicle Dynamics Control sys- tem. Do not deactivate the Vehicle
Dynamics Control system except when
absolutely necessary..
Even when the Vehicle Dynamics
Control OFF mode is selected, compo-
nents of the brake control system may
still activate. When the brake control
system is activated, the Vehicle Dy-
namics Control operation indicator
light illuminates.
& Vehicle Dynamics Control
OFF switch (except STI)
Indicator light (turbo models)
Indicator light (non-turbo models)
Vehicle Dynamics Control OFF switch
Pressing the switch to deactivate the
Vehicle Dynamics Control system can
facilitate the following operations: . a standing start on a steeply sloping Starting and operating
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7-38Starting and operating
road with a snowy, gravel-covered, or
otherwise slippery surface .extrication of the vehicle when its
wheels are stuck in mud or deep snow
When the switch is pressed during engine
operation, the Vehicle Dynamics Control
OFF indicator light on the combination
meter illuminates. The Vehicle Dynamics
Control system will be deactivated and the
vehicle will behave like a model not
equipped with the Vehicle Dynamics Con-
trol system. When the switch is pressed
again to reactivate the Vehicle Dynamics
Control system, the Vehicle Dynamics
Control OFF indicator light turns off.
With the Vehicle Dynamics Control system
deactivated, traction and stability en-
hancement offered by Vehicle Dynamics
Control system is unavailable. Therefore
you should not deactivate the Vehicle
Dynamics Control system except under
above-mentioned situations. NOTE . The Vehicle Dynamics Control sys-
tem will be activated automatically
when the engine is started.. If the switch is held down for 10
seconds or longer, the indicator light
turns off, the Vehicle Dynamics Control
system is activated, and the system
ignores any further pressing of the switch. To make the switch usable
again, turn the ignition switch to the“
LOCK ”position and restart the en-
gine.. When the switch is pressed to
deactivate the Vehicle Dynamics Con-
trol system, the vehicle ’s running per-
formance is comparable with that of a
vehicle that does not have a Vehicle
Dynamics Control system. Do not de-
activate the Vehicle Dynamics Control
system except when absolutely neces-
sary.. Even when the Vehicle Dynamics
Control system is deactivated, compo-
nents of the brake control system may
still activate. When the brake control
system is activated, the Vehicle Dy-
namics Control operation indicator
light illuminates. Tire pressure monitoring
system (TPMS) (U.S.-spec.
models)
Turbo models
Non-turbo models