brake PORSCHE 911 2009 5.G User Guide

34
Operation, Safety
Operating with the remote control of the
vehicle keyEach remote control (up to six) can be assigned an
individual seat and door mirror position.
The stored seat and door mirror position is set au-
tomatically when the vehicle is unlocked using the
corresponding remote control.
Storing seat position
1. Switch the ignition on with the desired car key.
Reverse gear must not be engaged.
2. Set the desired seat and door-mirror positions.
3. Keep memory button M depressed and also
press key button 1 until an audible signal
confirms that the position has been stored.
The individual setting is now assigned to this
remote control and to the key button.
It is necessary to wait for at least 15 seconds
between locking and unlocking the door.Storing individual lowered position of the
passenger’s door mirror as a parking aid
Once the driver's seat setting has been stored, an
individual lowered position of the passenger's
door mirror may be stored for driving in reverse:
1. Apply the handbrake.
2. Switch the ignition on with the desired car key.
3. Engage reverse gear.
4. Select passenger side with mirror switch.
The passenger’s mirror swivels downwards.
5. Set passenger’s door mirror to desired final
position.
6. Keep memory button M depressed and also
press key button 1 until an audible signal
confirms that the position has been stored.
The individual setting is now assigned to this
remote control and to the key button.Recalling seat position
fUnlock the locked vehicle or the luggage
compartment with the remote control.
The stored seat position is automatically set.
The seat position assigned to a remote control
can also be recalled with the key button 1 if the
corresponding key was used to switch on the
ignition.
If no seat position has been assigned to a remote
control, the key button will not work.
Note on operation
Automatic seat adjustment can be interrupted
immediately:
fby switching on the ignition,
fby pressing the central locking button,
fby pressing any memory or seat adjustment
button.
Clearing the stored seat position
1. Switch the ignition on with the desired car key.
2. Press memory button twice and key button 1
once consecutively.

Operation, Safety
57
Sports Exhaust SystemSwitching on and offThe sports exhaust system can be switched on
and off when the ignition is switched on using
button A.
When the sports exhaust system is switched on,
the light-emitting diode in the button lights up.
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” (PDK) 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.

58
Operation, Safety 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” (PDK) 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.
To prevent corrosion of the brake discs, “brake
them dry” before parking the car.
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, resulting in serious per-
sonal injury or death.
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

Operation, Safety
59
Brake system warning light
You can check the functionality of the brake
system warning light by switching the ignition to
the "On" position and verifying that the warning
light illuminates.
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, resulting in serious per-
sonal injury or death.
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

60
Operation, Safety
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 or sanded
roads for extended periods, the brakes should be
washed down thoroughly about every 2 weeks. An
automatic carwash facility cannot do this job prop-
erly.
Brakes will dry after a few cautious brake applica-
tions.
Warning!
Risk of an accident, resulting in serious per-
sonal injury or death.
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 ex-posure to road water, etc.
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.
Brake system warning light
You can check the functionality of the brake
system warning light by switching the ignition to
the "On" position and verifying that the warning
light illuminates.
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

Operation, Safety
61
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.
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.
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.
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 au-
dible 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.
fIf full braking should be necessary, press the
brake pedal all the way down throughout the
entire braking procedure, regardless of the pul-
sating pedal. Do not ease up on pressure ap-
plied to the pedal.
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.

62
Operation, Safety 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!
Risk of an accident, resulting in serious per-
sonal injury or death.
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.
Clutch Pedal The clutch pedal must be depressed fully
before the starter will engage.
Warning!
Risk of an accident, resulting in serious per-
sonal injury or death.
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.
Warning light USA
Warning light Canada

Operation, Safety
63
Porsche Traction Management
(PTM)With PTM, the engine power is variably distributed
to the front and rear wheels.
Power distribution between the front and rear ax-
les is performed by a map-conrolled multiple-disc
clutch.
Distribution of the engine power also depends on
the difference in wheel speed between the two ax-
les.
The multiple-disc clutch always delivers sufficient
drive power to the front wheels to ensure optimum
propulsion even on an unfavorable road surface.
In combination with the Porsche Stability Manage-
ment (PSM), the PTM ensures optimum handling
and high 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 PTM.
The risk of accidents due to inappropriate
speed cannot be reduced, even by PTM.
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 vehicle 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 dy-
namometer.
Warning!
Risk of severe powertrain damage and a pos-
sible unexpected movement of the vehicle.
fDo not test your vehicle on a two-wheel dyna-
mometer.
fAdvise the emission station of this warning be-fore testing the vehicle.
Brake testsBrake tests must be performed only on plate-type
test stands or roller test stands.
The ignition must be off.
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 only
be carried out 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 see the chapter “TOWING” on
Page 280.Wheels/TiresThe PTM control unit is adapted to the approved
tire sizes. The use of non-approved tire sizes may
lead to deviations in wheel speeds and it may influ-
ence handling or result in the PTM switching off.

66
Operation, Safety
Porsche Stability Management
(PSM)PSM is an active control system for stabilization of
the vehicle approaching the performance limits of
driving maneuvers.
Warning!
Risk of an accident, resulting in serious per-
sonal injury or death.
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 PSM.
The risk of accidents due to inappropriate
speed cannot be reduced, even by PSM.
The driver bears the responsibility for all
driving maneuvers.
fAdapt your driving style to the prevailing road
and weather conditions.
fObey all traffic laws.
Sensors at the wheels, brakes, steering system
and engine continuously measure:
–Speed
– Direction of travel (steering angle)
– Lateral acceleration
– Rate of turn about the vertical axis
– Longitudinal accelerationPSM uses these values to determine the direction
of travel indicated by the driver.
PSM intervenes and helps to correct the course if
the actual direction of motion deviates from the
chosen course (steering-wheel position):
It brakes individual wheels as needed. In addition,
the engine power may be manipulated in order to
stabilize the vehicle.
The events below inform the driver of PSM control
operations and warn him/her to adapt his/her
driving style to the road conditions:
– The multifunctional information light on the
instrument panel flashes.
– Hydraulic noises can be heard.
– The vehicle decelerates and steering-wheel
forces are altered as the PSM controls the
brakes.
– Reduced engine power.
– The brake pedal pulsates and its position is
changed during braking.
In order to achieve full vehicle deceleration,
foot pressure must be increased after the
brake pedal has begun vibrating.
Examples of PSM control operations– If the front wheels of the vehicle drift on a
bend, the rear wheel on the inside of the bend
is braked and the engine power is reduced if
necessary.
– If the rear of the vehicle swings out on a bend,
the front wheel on the outside of the bend is
braked.Additional braking functions– Pre-filling the brake system:
The brake system is prepared for possible
subsequent emergency braking if the acceler-
ator pedal is released suddenly and quickly.
The brake system is prefilled and the brake
pads are already applied gently to the brake
discs.
– Brake booster:
In the event of an emergency braking operation
where the pedal force is insufficient, a brake
booster provides the braking pressure neces-
sary for maximum deceleration at all 4 wheels.Advantages of PSM– Best possible traction and lane-holding ability
in all driving situations – even on road surfaces
with varying friction.

Operation, Safety
67
– The system compensates for undesired lateral
vehicle reactions when the driver releases the
accelerator pedal or brakes when cornering.
This compensation functions up to the
maximum lateral acceleration.
– PSM actively stabilizes the vehicle as required
during dynamic driving maneuvers (e.g. rapid
steering movements, during lane changes or
on alternating bends).
– Improved braking stability on bends and on
different or varying road surfaces.
– It improves braking function and shortens
stopping distance in the event of emergency
braking.Readiness for operationPSM is switched on automatically every time you
start the engine.
PSM should always be switched on during
“normal” driving.
However, it may be advantageous to switch off
PSM temporarily in exceptional situations, for
example:
– On a loose surface or in deep snow,
– When “rocking” the vehicle free and
– When using snow chains.
Switching off PSMfPress PSM OFF button.
PSM is switched off after a short delay.
The light-emitting diode in the button is lit up.
When the PSM is switched off, the PSM multi-
functional light on the instrument panel is lit
and a message is shown on the on-board
computer.
An acoustic signal also sounds.
Note
When PSM is switched off, the additional braking
functions are deactivated. Automatic reactivation
in emergency situations is linked to the PSM
control.The following functions stabilize the vehicle in
emergency situations, even with PSM switched
off:
– When PSM is off, the vehicle is stabilized as
soon as one of the two front wheels enters the
ABS control range.
– When PSM is off and Sport mode is on, the
vehicle is stabilized as soon as both front
wheels enter the ABS control range.
One-sided spinning of the wheels is prevented,
even with PSM switched off.
Switching PSM back onfPress PSM OFF button.
PSM is switched on after a short delay.
The light-emitting diode in the button and the
PSM multifunctional light on the instrument
panel go out.
The on-board computer shows a message.