PORSCHE 911 CARRERA 2006 5.G Repair Manual

Controls, Instruments
61
Four-Wheel Drive With the four-wheel drive of the 911 Carrera 4 and
911 Carrera 4S, the engine power is variably dis-
tributed to the front and rear wheels.
Power distribution and wheel speed compensation
between the front and rear axles is realised with a
viscous multiple-disc clutch.
Distribution of the engine power is dependent
upon the wheel speed difference between the two
axles.
The viscous multiple-disc clutch always delivers
sufficient drive power to the front wheels (approx.
5% to 40%) to ensure optimum traction even on a
poor road surface.
In combination with the Porsche Stability Manage-
ment (PSM), four-wheel drive improves handling
and increases driving stability.
Warning!
The increased control that is provided should
not induce you to take greater risks with your
safety. The limits dictated by the laws of phy-
sics cannot be overcome, even with four-
wheel drive.
The risk of accidents due to inappropriate
speed cannot be reduced, even by four-
wheel drive.
The driver bears the responsibility for all dri-
ving maneuvers.
fAdapt your driving style to the prevailing road
and weather conditions.
fObey all traffic laws.
Dynamometer testing procedure Some U.S. states and Canadian provinces con-
duct emissions inspection/maintenance testing in-
volving the use of two-wheel dynamometer.
A two-wheeled dynamometer is a treadmill type
device upon which a single axle of the car, the dri-
ving axle of the vehicle, rotates to simulate vehicle
operation on the road while the vehicle remains
stationary.
Your 911 Carrera 4 or 911 Carrera 4S has a full-
time four-wheel drive system which cannot be
disabled. Severe damage to the powertrain can
result if tested on a two-wheel dynamometer.
Warning!
To avoid severe powertrain damage and a
possible unexpected movement of the vehic-
le.
fYour 911 Carrera 4 or 911 Carrera 4S vehicle
must never be tested on a two-wheel dynamo-
meter.
fAdvise the emission station of this warning be-fore testing the vehicle.
Power measurement
Power measurements on dynamometers are not
approved by Porsche.

62
Controls, Instruments
Brake tests Brake tests must be performed only on plate-type
test stands or roller test stands.
The following limit values must not be exceeded
on roller test stands:
– Testing speed 5 mph (8 km/h)
– Test duration 20 seconds Handbrake tests Handbrake tests on the roller test stand must be
performed only with the ignition switched off. Balancing wheels on the vehicle During finish balancing of the wheels, the vehicle
must be hoisted and all the wheels able to rotate
freely. Towing fPlease observe the chapter “TOWING” on
Page 281.

Controls, Instruments
63
Retractable Rear SpoilerThe rear spoiler improves driving stability,
especially at higher speeds.
Warning!
Risk of accident. If the rear spoiler cannot be
extended, driving stability will be adversely
affected by increased rear axle lift, which
could lead to loss of control.
fAdapt your driving style and speed to the
changed driving behaviour.
fHave the fault remedied at an authorized
Porsche dealer.
Risk of injury during manual retraction or
extension of the rear spoiler with the vehicle
stationary.
fMake sure that no persons or objects are
within the range of movement of the rear
spoiler.
Risk of damage from pushing the vehicle by
the spoiler.
fDo not push the vehicle at the spoiler.
Automatic modeThe limits for automatic extension and retraction
of the spoiler depend on various circumstances
(e.g. driving speed, engine compartment temper-
ature).
Engine compartment temperature
under 122°F/55°C
Spoiler extends at 75 mph/120 km/h and
retracts at 37 mph/60 km/h.
Engine compartment temperature
over 140°F/60°C
Spoiler extends at 50 mph/80 km/h and retracts
at 19 mph/30 km/h.
If automatic control fails, a warning message is
displayed by the on-board computer.

64
Controls, Instruments When the ignition is on, the rear spoiler can be
extended and retracted manually using the button
in the center console.
Extending
fPress button briefly.
The spoiler extends to its final position.
The light-emitting diode in the button lights up.Retracting a manually extended rear spoiler
fat speeds between 0 and 20 mph
(0 and 30 km/h)
Press and hold button until the rear spoiler has
reached its final position.
The light-emitting diode in the button goes out.
The rear spoiler changes to automatic mode.
fat speeds between 20 and 60 mph
(30 and 100 km/h)
Press button briefly.
The rear spoiler retracts, the light-emitting
diode in the button goes out.
The rear spoiler changes to automatic mode.
fat speeds over 60 mph (100 km/h)
Press button briefly.
The rear spoiler remains extended, the light-
emitting diode in the button goes out.
The rear spoiler changes to automatic mode.Manual control

Controls, Instruments
65
Clutch Pedal The clutch pedal must be depressed fully
before the starter will engage.
Warning!
Risk of an accident.
fAlways check the movement of the clutch ped-
al before driving and make sure that it is not
obstructed by a floor mat or any other object.
fSecure the floor mat to prevent it from sliding
into positions that could interfere with the safe
operation of your vehicle.
Your Porsche dealer will be glad to offer you
nonskid floor mats of the correct size.
To avoid damage to the clutch and transmis-
sion:
fAlways depress the clutch pedal fully when
changing gears.
fDo not hold the car on a steep grade with the clutch pedal partially depressed.
Should the free travel of the clutch pedal suddenly
become larger, it could mean a malfunction of the
clutch.
fSee your Porsche dealer for correction.
Parking Brake Parking brake force is mechanically transferred to
the rear wheels by means of cables.
fUse the parking brake only after the vehicle
has come to a full stop.
Setting the parking brake fPull the lever all the way up (arrow).
With the ignition on, the parking brake warning
lights in the instrument panel and on-board
computer will come on if the lever is even
slightly raised. A firm pull upward is required to
properly engage the parking brake.
If the brake is not fully set, the vehicle may roll
without control.
fMove the selector lever to “P” (Tiptronic) or
move the gearshift lever to reverse or first
gear (Manual transmission).
fBefore exiting the vehicle, make sure that the
parking brake is fully set and the vehicle is not
moving at all.
Danger!
Risk of serious personal injury or death. A
partially engaged parking brake may allow
the vehicle to roll, causing serious personal
injury or death to any person in its path.
fEngage the parking brake fully.Releasing the parking brakefPull the lever slightly up as you depress the re-
lease button, and then push the lever all the
way down.

66
Controls, Instruments The warning lights in the instrument panel and on-
board computer will go out after the parking brake
is fully released.
The warning lights are not an indicator that the
parking brake is fully set; it is only intended to be
a warning to release the parking brake before
driving the car. Caution!
A partially engaged brake will overheat the
rear brakes, reduce their effectiveness and
cause excessive wear.
fRelease the parking brake fully.
fWhen parking your car, always set the parking
brake by pulling all the way up on the lever.
fMove the selector lever to “P” (Tiptronic) or
move the gearshift lever to reverse or first
gear (Manual transmission).
fOn hills also turn the front wheels towards the
curb.
Brakes fMake it a habit to check the operation of your
brakes before driving.
Keep in mind that the braking distance increases
very rapidly as the speed increases. At 60 mph or
100 km/h, for example, it is not twice but four
times longer than 30 mph or 50 km/h. Tire trac-
tion is also less effective when the roads are wet
or slippery.
fTherefore, always maintain a safe distance
from the car in front of you.
Vehicles without Porsche Ceramic Compos-
ite Brake (PCCB)
Even though the brake discs consist of alloyed
grey cast iron, they will unavoidably start to cor-
rode if your car is parked for an extended period.
The brakes will tend to “rub” as a result.
The nature, extent and effects of corrosion de-
pend on the amount of time the vehicle was
parked, whether granular or liquid road salt was
spread and whether grease-dissolving agents
were used in car washes.
If the braking comfort is noticeably impaired, we
recommend having the brake system checked by
experts at an authorized Porsche dealer.
Brake system function Your Porsche is equipped with a power assisted
hydraulic dual circuit brake system with disc
brakes at the front and rear.
Both circuits function independently. One brake
circuit operates the front and the other operates
the rear.
If one brake circuit has failed, the other will still op-
erate. However, you will notice an increased pedal
travel when you apply the brakes.
Failure of one brake circuit will cause the stopping
distance to increase.
Warning!
Risk of an accident.
In the unlikely event of hydraulic failure of
one brake circuit:
fPush the brake pedal down firmly and hold it in
that position.
A mechanical linkage activates the second cir-
cuit, and you will be able to bring the vehicle to
a stop.
fAfter bringing your vehicle to a complete stop,
avoid driving the vehicle and instead have it
towed to the nearest authorized Porsche deal-er for repair.
Parking brake warning light USA
Parking brake warning light
Canada

Controls, Instruments
67
If the warning lights in the instrument panel and on-
board computer go on while driving, the brake flu-
id level may be too low, or (if the brake pedal travel
has increased) one of the two brake circuits may
have failed.
A greater braking pressure will be required, stop-
ping distances will be longer and the braking be-
havior will change, particularly in curves.
With correctly adjusted brakes, and a correctly
working brake system, the pedal travel to the
point of brake actuation should be 1-3/16 in. to
1-9/16 in. or 30 to 40 mm.
Whenever the brake pedal travel exceeds this dis-
tance, have the brake system checked.
Brake pedal
Warning!
Risk of an accident.
Any obstruction of the brake pedal could
increase the stopping distance.
fAlways check the movement of the brake pedal
before driving and make sure that it is not ob-
structed by a floor mat or any other object.
fSecure the floor mat to prevent it from sliding
into positions that could interfere with the safe
operation of your vehicle.
Your Porsche dealer will be glad to offer you nonskid floor mats of the correct size.
Note
In case one of the two brake circuits fails, in-
creased pedal travel is required to bring your
vehicle to a full stop.
Warning!
To avoid overheating and premature wear of
the brakes:
fBefore descending a steep grade, reduce
speed and shift the transmission into a lower
gear or driving position to control speed.
fDo not “ride the brakes” by resting your foot on
the pedal when not intending to apply brake
pressure.
fDo not hold the pedal down too long or too
often.
This could cause the brakes to get hot and not function properly.
Brake warning light USA
Brake warning light Canada

68
Controls, Instruments
Brake booster The brake booster assists braking only when
the engine is running.
When the car is moving while the engine is not run-
ning, or if the brake booster is defective, more
pressure on the brake pedal is required to bring
the car to a stop.
If this happens, ABS and PSM will also not oper-
ate.
Moisture or road salt on brakes affects braking.
When the vehicle is driven on salted roads for ex-
tended periods, the brakes should be washed
down thoroughly about every 2 weeks. An auto-
matic carwash facility cannot do this job properly.
Brakes will dry after a few cautious brake applica-
tions.
Warning!
Driving through water may reduce the trac-
tion.
Moisture on brakes from road water, car
wash, or coating of road salt may affect
braking efficiency.
fCautiously apply brakes to test brakes after being exposed.
Brake wear Your car has excellent brakes, but they are still
subject to wear. The rate at which they wear de-
pends on how the brakes are used.
fHave the brake system inspected at the
intervals recommended in your Maintenance
Booklet.
If the warning lights in the instrument panel and on-
board computer stay on when the engine is run-
ning or come on while driving, the brake pads are
worn, excessively.
fDo not continue to operate the vehicle.
Have your authorized Porsche dealer inspect
or replace the brake pads.
Brake pads Wear on the brake pads and brake discs depends
to a great extent on the driving style and the con-
ditions of use and therefore cannot be expressed
in actual miles on the road.
The high-performance brake system is designed
for optimal braking effect at all speeds and tem-
peratures.
Certain speeds, braking forces and ambient
conditions (such as temperature and humidity)
therefore might cause “brake noises”.
New brake pads or linings
New brake pads and brake discs have to be “bro-
ken in”, and therefore only attain optimal friction
when the car has covered several hundred miles
or km.
The slightly reduced braking ability must be com-
pensated for by pressing the brake pedal harder.
This also applies whenever the brake pads and
brake discs are replaced.
Warning light USA
Warning light Canada

Controls, Instruments
69
ABS Brake System
(Antilock Brake System)The ABS system represents a major contribution
to the enhancement of active safety in your vehi-
cle. This system prevents the wheels from locking
in a panic stop on almost all road surfaces. With the ABS system in your vehicle, the
following areas are enhanced:
Steering, vehicle remains steerable under all
braking forces when ABS is engaged.
Good directional control, no swerving caused
by locking of wheels under braking conditions.
Shorter stopping distance, stopping distances
are usually reduced because controlled braking is
maximized.
Prevention of wheel lock up, no brake- induced
sliding and thus no localized tire wear from emer-
gency braking.
The crucial advantage of the ABS system over a
conventional brake system is in the area of main-
taining directional control and maneuverability of
the car in emergency situations during normal driv-
ing, including panic braking in turns.
Warning!
The increased control that is provided should
not induce you to take greater risks with your
safety. The limits dictated by the laws of
physics cannot be overcome, even with ABS.
The risk of accidents due to inappropriate
speed cannot be reduced, even by the ABS.
The driver bears the responsibility for all
driving maneuvers.
fAdapt your driving style to the prevailing road
and weather conditions.
fObey all traffic laws.
Other vehicles not equipped with the ABS
system may not be able to maintain control,
especially on wet or poor road surfaces and
thus may be more likely to impact you from
behind.
fTo minimize that risk, use your ABS system to
increase your ability to maneuver to avoid dan-
gerous situations and not merely to try to stop in the shortest distance possible.

70
Controls, Instruments
Operation of the ABS systemA wheel speed sensor is mounted to each of the
four wheels. If wheel lock-up of either of the front
wheels or the rear wheels is sensed during brak-
ing, the brake pressure is adjusted automatically
until the wheel no longer slips. The brake pressure
is regulated for each front wheel individually and
for both of the rear wheels together.
On a road surface which is slippery on only one
side, the rear wheel which is braking on the slip-
pery surface determines the brake pressure which
will be applied equally to both rear wheels. This en-
sures that directional stability is maintained. How-
ever, if braking forces approach the wheel lock-up
point for all wheels (panic braking) the ABS system
will intervene to provide a rapid rythmic braking.
The proper operation of ABS is perceived by the
driver as a pulsating brake pedal in conjunction
with audible noise and perhaps some vibration.
fIf you experience these sensations while driv-
ing or a road surface with questionable trac-
tion, reduce vehicle speed appropriate for the
prevailing road conditions.
The functional readiness of all the main electrical
components of the ABS is checked by an
electronic monitoring system both before and
while you drive. When the ignition is switched on the ABS warning
light will light up while the system is electronically
interrogated and goes out when the engine is
started if the check is not yet complete.
If the ABS warning lamp fails to go out, this indi-
cates that ABS has been deactivated due to a
fault. If the warning lights in the instrument panel
and on-board computer light up while you are driv-
ing, this indicates that a fault has occurred. In both
cases, normal braking, as in vehicles without ABS,
is still retained.
The ABS system should, however, be examined at
an authorized Porsche dealer immediately to pre-
vent the occurrence of further faults.
fIf the ABS system becomes inoperative, take
your vehicle to your authorized Porsche dealer
immediately.
Warning!
The control unit of the ABS brake system is
set for standard tire size. If non-standard
tires are installed, the control unit may mis-
interpret the speed of the vehicle, because of
the variant data it receives from the sensors
on the axles.
fUse only tire makes and types tested by Porsche.
Warning light USA
Warning light Canada