2005 SUBARU IMPREZA WRX Owners Manual

7-18
Starting and operating
Driver’s Control Center Differential
(DCCD) (WRX-STi)
Always use the utmost care when driving. Be-
ing overconfident because you are driving a ve-
hicle with a driver’s control center differential
could easily lead to a serious accident.
In the event of failure of the driver’s control
center differential, the “ ” indicator light will
flash and the auto mode and manual mode will
both stop functioning. Have the vehicle in-
spected by your Subaru dealer.
„ Auto mode
This system automatically adjusts the differential-ac-
tion limiting factor (torque-distribution ratio between
the front and rear wheels) of the center differential to
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Starting and operating
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suit driving and road-surface conditions. When the ig-
nition switch is turned ON, the “AUTO” indicator light
in the combination meter comes on. The system can
be switched to a manual mode. „Manual mode
The manual mode allows the driver to set the differen-
tial-action limiting factor of the center differential as
desired to suit driving and road-surface conditions.
When this mode is selected, the “AUTO” indicator light
in the combination meter goes off. T Manual switch
Press the “DCCD-MANU” switch on the center con- sole to switch from auto mode to manual mode. The
“AUTO” indicator light in the combination meter will go
off. Press the switch again to go back to auto mode.
The “AUTO” indicator light in the combination meter
will come on. T
Center differential control dial and indicator
light
The control dial is located beside the parking-brake le-
ver. By turning the control dial forward and rearward,
it is possible to change the differential-action limiting
factor of the center differential.
The center-differential indicator lights in the combina-
tion meter give six levels of indication. The indicator
MANU
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7-20
Starting and operating
lights and control dial are linked; when the dial is
turned to change the differential-action limiting factor
(front/rear torque-distribution ratio), the illumination
position of the indicator lights change accordingly.
Turn the dial forward to increase the differential-action
limiting factor. If the white line on the dial reaches the
frontmost position, the center differential will be almost
completely locked and the “LOCK” indicator light will come on.
Turn the dial rearward to reduce the differential-action
limiting factor. If the white line on the dial reaches the
rearmost position, the factor will be minimal and the
“ ” indicator light will come on.
y
Do not turn the control dial when a wheel slip-
page occurs. Wait until the wheelspin has been
brought under control or select the auto mode. y When the vehicle has been fitted with a tem-
porary spare tire or is to be towed, turn the con-
trol dial fully rearward (to minimize the differen-
tial-action limiting factor) or select the auto
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7-21
Starting and operating
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mode.
NOTE yIf the differential-limiting factor is large during
cornering maneuvers, a small speed difference
between the front and rear wheels may cause tight
corner braking (a phenomenon accompanied by
vibration and noise). This phenomenon does not
indicate a problem. It will disappear if the differen-
tial-action limiting factor is reduced.y Use the center-differential indicator light only as
a rough indication of the differential-action limit-
ing factor.y If you rapidly depress and release the accelera-
tor pedal while driving at low speed, you may hear
a knocking sound from the vicinity of the center
differential and rear differential. This sound oc-
curs because of the structure of the center differ-
ential. It does not indicate a problem. „ Temporary release
When the driver stop the vehicle and pulls the parking-
brake lever after manually setting the differential-ac-
tion limiting factor, the factor is temporarily minimized.
The indicator in the combination meter continues to
show the driver’s selected differential-action limiting factor. When the driver releases the parking-brake le-
ver, the factor set by the driver is restored.

7-22
Starting and operating
Automatic transmission
The automatic transmission is electronically controlled
with 4-forward speeds and 1-reverse speed.
NOTE
Immediately after a disconnected battery is recon-
nected (Turbo model only) or ATF (automatic
transmission fluid) is replaced, you may feel that
the automatic transmission operation is some-
what unusual.
This results from erasure or invalidation of data
the on-board computer has collected and stored in memory to allow the transmission to shift at the
most appropriate times for the current condition
of your vehicle. Optimized shifting will be restored
as the vehicle continues to be driven for a while.
Do not shift from the “P” or “N” position into
the “D”, “3”, “2”, “1” or “R” position while de-
pressing the accelerator pedal. This may cause
the vehicle to jump forward or backward.
y
Shift into the “P” or “R” position only after
the vehicle is completely stopped. Shifting
while the vehicle is moving may cause damage
to the transmission.y Do not race the engine for more than five sec-
onds in any position except the “N” or “P” po-
sition when the brake is set or the tires are on
blocks. This may cause the automatic transmis-
sion fluid to overheat. y Avoid shifting from one of the forward driving
positions into the “R” position or vice versa un-
til the vehicle has completely stopped. Such
shifting may cause damage to the transmis-
sion.

7-23
Starting and operating
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„Selector lever for automatic transmis- sion
: With the brake pedal depressed, move the lever along the gate.
: Move the lever along the gate.
The selector lever has seven positions. T P (Park)
This position is for parking the vehicle and starting the
engine.
In this position, the transmission is mechanically
locked to prevent the vehicle from rolling freely.
When you park the vehicle, first set the parking brake
fully, then shift into the “P” position. Do not hold the ve-
hicle with only the transmission.
P
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Starting and operating
A shift interlock function is employed in the automatic
transmission system to ensure safe starting of the ve-
hicle.
To shift the selector lever from the “P” to the any other
position, you have to depress the brake pedal fully
when the ignition switch is in the “ON” position. This
prevents the vehicle from lurching when it is started.
If the shift lever does not move from the “P” position
with the brake pedal depressed, refer to the “Shift lock
release” section in this chapter. T
R (Reverse)
This position is for backing the vehicle.
To shift from the “N” to “R” position, first stop the vehi-
cle completely then move the lever to the “R” position. T N (Neutral)
This position is for restarting a stalled engine.
In this position the wheels and transmission are not
locked. In this position, the transmission is neutral; the
vehicle will roll freely, even on the slightest incline un-
less the parking brake or foot brake is on.
NOTE (Except Turbo models)
If you stop the engine with the selector lever in the
“N” position, move the selector lever to the “P”
position immediately. Otherwise, you may find that the selector lever soon cannot be moved to
the “P” position. If you find that the selector lever
cannot be moved from the “N” position to the “P”
position, turn the ignition switch to the “ON” posi-
tion and try again.
Do not drive the vehicle with the selector lever
in the “N” (neutral) position. Engine braking
has no effect in this condition and the risk of an
accident is consequently increased.
T D (Drive)
This position is for normal driving.
The transmission automatically shifts into a suitable
gear from 1st to 4th according to the vehicle speed
and the acceleration you require.
When more acceleration is required in this position,
press the accelerator pedal fully to the floor and hold
that position. The transmission will automatically
downshift to 3rd, 2nd or 1st gear. When you release
the pedal, the transmission will return to the original
gear position.

7-25
Starting and operating
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VWhile climbing a grade
When driving up hill, undesired upshift to 4th gear is
prevented from taking place when the accelerator
pedal is released. This minimizes the chances of sub-
sequent downshifting to a lower gear when accelerat-
ing again. This prevents repeated upshifting and
downshifting resulting in a smoother operation of the vehicle.
NOTE
The transmission may downshift to 2nd or 1st
gear, depending on the way the accelerator pedal
is pressed to accelerate the vehicle again. V While going down a hill
When descending a steep hill, depressing the brake
pedal will cause the transmission to downshift to 3rd
gear, thus applying engine braking. Reacceleration for
a short time will cause the transmission to upshift nor-
mally.
NOTE
In some cases, depressing the brake pedal on a
downhill grade does not result in an automatic
downshift to 3rd gear. This can happen when the
automatic transmission fluid temperature is very
low, for example, during driving shortly after the
vehicle has been parked for an extended period of time. When the ATF temperature has risen to a cer-tain level, automatic downshift normally takes
place. In the meantime, downshift manually for en-
gine braking as required.
Also, downshifting when braking downhill will not
occur at speeds above approximately 48 mph (78 km/h). T
3 (Third)
This position is for using engine braking when going
down a hill or for climbing a grade.
The transmission automatically shifts into a suitable
gear from 1st to 3rd according to the vehicle speed
and the acceleration you require.
When more acceleration is required in this position,
press the accelerator pedal fully to the floor and hold
that position. The transmission will automatically
downshift to 2nd or 1st gear. When you release the
pedal, the transmission will return to the original gear
position. T 2 (Second)
This position is for using engine braking when going
down a hill or for climbing a steep grade.
In this position, the transmission holds in the 2nd gear.
Use this position when starting off from a standstill on
slippery road surfaces such as mud or snow. It will en-