2004 PORSCHE CAYENNE brake light

Driving and Driving Safety
165
Brake boosterThe brake booster assists braking only when
the engine is running.
When the car is moving while the engine is not
running, or if the brake booster is defective, more
pressure on the brake pedal is required to bring
the car to a stop.
Moisture, road salt or grit on brakes affects
braking.
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 a coating of road salt or grit may
affect braking efficiency.
fCautiously apply brakes to test brakes after exposure to road water, etc.
Brake wearYour car has excellent brakes, but they are still
subject to wear. The rate at which they wear
depends on how the brakes are used.
fHave the brake system inspected at the inter-
vals recommended in your Maintenance Book-
let.
Brake system warning light
You can check the functionality of the brake sys-
tem warning light by switching the ignition to the
“On” position and verifying that the warning light
illuminates.
A warning message will be displayed on the multi-
purpose display of the instrument panel if the
brake pads are worn, excessively.
fDo not continue to operate the vehicle.
Have your authorized Porsche dealer inspect
or replace the brake pads.
fPlease see the chapter “OVERVIEW OF
WARNING MESSAGES” on Page 149.
Brake pads and brake discsWear 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 the brakes to squeal.
Brake wear warning message
10_Cayenne_21_KW17.book Seite 165 Donnerstag, 9. April 2009 3:33 15

166
Driving and Driving Safety New brake pads or linings
New brake pads have to be “broken in”, and there-
fore 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!
fDo not obstruct the pedal travel with floor mats
or other objects.
The brake booster is ready for operation only
while the engine is running.
If the engine is switched off or there is a defect in
the brake booster, much greater force has to be
applied to the pedal when braking.
fPlease see the chapter “TOWING” on
Page 342.
In heavy rain, while driving through water or after
leaving a car wash, the braking action may be
delayed and increased pressure may be required.
fFor this reason, keep further back from the ve-
hicle in front and “dry” the brakes by applying
them at intervals. Make sure that following traf-
fic is not affected.
After a long drive over salted or sanded roads, a
coating may form on the brake discs and pads
that significantly reduces friction and thus braking
action.fEven though the brake discs consist of alloyed
grey cast iron, they will unavoidably start to
corrode 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
depend on the amount of time the vehicle was
parked, whether road salt or grit was spread
and whether grease-dissolving agents were
used in car washes (not on vehicles with
Porsche Ceramic Composite Brake).
To prevent corrosion of the brake discs, “brake
them dry” before parking the car (not on
vehicles with Porsche Ceramic Composite
Brake).
If the braking comfort is noticeably impaired,
we recommend having the brake system
checked by experts at an authorized Porsche
dealer.
fTo relieve the braking system on downhill
stretches, change down to a lower gear in
enough time to obtain engine braking.
If engine braking is insufficient on steep
stretches, operate the footbrake at intervals.
Continuous braking overheats the brakes and
reduces the braking effect.
fPlease see the chapter “BRAKE-FLUID LEVEL”
on Page 257.
10_Cayenne_21_KW17.book Seite 166 Donnerstag, 9. April 2009 3:33 15

168
Driving and Driving Safety
DeceleratingOption 1
fPush operating lever down into position 4 until
the desired speed is reached.
The speed reached is maintained and stored
when the operating lever is released.
Option 2
fPush operating lever slightly downwards into
position 4 (a maximum of 10 times).
The speed is reduced by 1 mph (2 km/h), each
time the lever is pushed downwards.
Interrupting cruise control operationThe speed driven before the interruption remains
stored in the memory and can be reactivated by
operating the operating lever. Please see the
chapter “RESUMING THE STORED SPEED” on
Page 168.
fPush the operating lever forward to position 2
(it doesn’t engage) or
fOperate brake or clutch pedal or, on vehicles
with Tiptronic S, select position N.
fPlease see the chapter “TIPTRONIC S” on
Page 170.
Cruise control operation is interrupted
automatically:
– If the set vehicle speed is exceeded by more
than approx. 16 mph (25 km/h) for longer than
20 seconds.
– If the actual vehicle speed falls by approx.
6 mph (10 km/h) below the set vehicle speed
for longer than 5 seconds (e.g. upward
slopes).
– If Porsche Stability Management (PSM)
intervenes for longer than 0.2 seconds.
– If Low Range is switched on.
Resuming the stored speedfPull back the operating lever to position 1.
Note on operation
The stored speed should only be recalled when
traffic conditions and the road surface so permit.Switching cruise control readiness offfPush forward the operating lever to position 2
until it clicks audibly into place.
The memory is cleared and the green
readiness light goes out.
When the vehicle is parked and the ignition
switched off, the memory is cleared.
Tip on driving
On upward or downward slopes, the set speed
cannot always be maintained by cruise control.
fTo obtain sufficient engine braking or a better
engine-speed range, therefore, you have to
change down to a lower gear.
10_Cayenne_21_KW17.book Seite 168 Donnerstag, 9. April 2009 3:33 15

174
Driving and Driving Safety
M - Manual selection mode (in the off-
road driving program)
Warning!
The kickdown function is not active in manual
selection mode “M”.
The kickdown function cannot be used to
downshift in manual selection mode “M”.
fTherefore shift down manually when accelera-ting (e.g. to overtake).
Tip on driving
The kickdown function is not active in selector
lever position M.
Unlike in the road driving program, an automatic
upshift is not performed when the engine-speed
limit is reached.Shifting up
fPress upper part (+) of a rocker switch A or
fPush selector lever B forward in the M gate.
Shifting down
fPress lower part (–) of a rocker switch A or
fPush selector lever B back in the M gate.
Depending on driving speed and engine speed,
you can shift up or down at any time. Gear
changes which would exceed the upper or lower
engine-speed limit are not executed by the control
unit.
You can change down two gears by quickly pres-
sing rocker switches A or selector lever B twice.
The gear is changed down automatically just
before idle speed is reached.
fSelect an appropriately low gear on upward
and downward slopes.
This will ensure optimum use of engine power
and engine braking.
If manual mode fails, the control electronics
switch to automatic mode. In this event, the instru-
ment panel will display selector lever position D.
fTo remedy the fault, please consult an
authorized Porsche dealer.
StoppingfFor a brief stop (e.g. at a traffic light), leave the
selector lever in drive position and hold the
vehicle with the brake pedal.
fDo not hold the car on a slope using the acce-
lerator. Use the brake pedal or the parking
brake instead.
fBefore leaving the vehicle, always apply the
handbrake and move the selector lever to
position P.
Tip on driving
In selector lever positions D and M, the hillholder
function makes it easier to move off from a stand-
still on an upward slope when the engine is run-
ning. The driver does not have to apply the brake.
fPlease see the chapter “HILLHOLDER -
MOVING-OFF ASSISTANT ON VEHICLES WITH
TIPTRONIC S” on Page 187.
10_Cayenne_21_KW17.book Seite 174 Donnerstag, 9. April 2009 3:33 15

Driving and Driving Safety
179
Note on operation
If the Low Range indicator light next to the rocker
switch flashes rapidly after the ignition is swit-
ched on, there is a fault in the shifting system.
fHave the vehicle checked immediately.
Please consult an authorized Porsche dealer.
If the Low Range indicator light next to the rocker
switch flashes when you attempt to operate
rocker switch, then at least one condition for shif-
ting has not been met:
Vehicles with manual transmission
– Vehicle is not stationary.
– Brake is not pressed.
– Gearshift lever in not in neutral.
Vehicles with Tiptronic S
– Vehicle has exceeded or gone below the limit
speed.
– Tiptronic selector lever is not in position N.
Sport ModeFunction
The sports exhaust system is switched on and a
sportier car set-up is obtained when Sport mode
is switched on.
Interventions by the Porsche control systems are
intentionally shifted towards greater agility and
driving performance.
– PASM (Porsche Active Suspension Manage-
ment) is automatically changed to Sport mode,
resulting in a stiffer suspension setup.– PDCC (Porsche Dynamic Chassis Control) is
automatically set to Sport mode, and this
further reduces the roll tendency of the
vehicle.
– The air suspension automatically changes to
the low level setting.
– The Tiptronic S transmission changes to a
sportier shift strategy.
The gear-changing points are shifted to higher
speed ranges. Upward shifts are initiated later,
and deceleration shifts are performed earlier.
The vehicle moves off in 1st gear.
– The electronic accelerator pedal reacts
sooner, and the engine is more responsive to
throttle inputs.
– Sporty engine tuning is activated.
fFor further information:
Please see the chapter “PORSCHE ACTIVE
SUSPENSION MANAGEMENT (PASM)” on
Page 193.
fPlease see the chapter “PORSCHE DYNAMIC
CHASSIS CONTROL (PDCC)” on Page 194.
Low Range indicator light
10_Cayenne_21_KW17.book Seite 179 Donnerstag, 9. April 2009 3:33 15

184
Driving and Driving Safety The events below inform the driver of PSM control
operations and warn him to adapt her/his driving
style to the road conditions:
– The multi-functional information light in the
instrument panel lights up.
– Light in the PSM Off button 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 begin-
ning of the brake pedal pulsing.
Examples of PSM control operations
– If the front wheels of the vehicle drift on a
corner, engine power is reduced and the rear
wheel on the inside of the corner is braked if
necessary.
– If the rear of the vehicle swings out on a
corner, the front wheel on the outside of the
corner is braked.– Brake system prefilling:
The brake system is prepared for possible sub-
sequent emergency braking if the accelerator
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.
Combined use of PSM and PTM/PTM Plus
In order to ensure optimal stabilization of the ve-
hicle, the center differential lock (PTM) and possib-
ly the rear differential lock (PTM Plus) are also
opened when PSM interventions occur.
Tip on driving
When PSM is switched off, wheel-specific brake in-
terventions and the traction control system (TCS)
are also inactive.
The automatic brake differential (ABD) remains on.Off-road PSM
(PSM in Low Range program)
When Low Range is active, an off-road PSM
specially matched to off-road driving is activated
to enhance traction.
In order to improve driveability on difficult terrain,
the response of the off-road PSM is less sensitive
in the low speed range when the vehicle is opera-
ted in the Low Range off-road driving program.
If the brakes are highly stressed, the automatic
brake differential (ABD) switches itself off to
protect the brakes. It remains deactivated until the
brake system has cooled sufficiently.
Engine drag torque control
In conditions of excessive slip, the engine drag
torque control system prevents all driven wheels
from locking up when the car is passing. This is
also the case for downshifts on a slippery road.
10_Cayenne_21_KW17.book Seite 184 Donnerstag, 9. April 2009 3:33 15

Driving and Driving Safety
185
Switching off PSMfPress PSM OFF button A.
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 multifunctio-
nal PSM light on the instrument panel is lit and
a message appears in the multi-purpose dis-
play of the instrument panel.During braking, the vehicle is stabilized even
when PSM is switched off.
One-sided spinning of the wheels is prevented,
even with PSM switched off.
PSM should always be switched on during
“normal” driving.
However, it can be of advantage to switch off PSM
temporarily in exceptional situations:
– On a loose surface or in deep snow
– When “rocking the vehicle free”
– When using snow chains.
Vehicles with Tiptronic: When the PSM is
switched off the slip monitoring function is also
deactivated.– The multifunctional light on the instrument pa-
nel lights up for a lamp check when the ignition
is switched on.
– The light indicates a control operation, inclu-
ding when PSM is switched off (brake control
in the event of one-sided wheel spin).
– In conjunction with the multi-purpose display on
the instrument panel, the light indicates that
PSM is switched off.
– Faults are displayed by the light in conjunction
with the multi-purpose display of the instru-
ment panel.
PSM is out of order.
fConsult your authorized Porsche dealer.
Multifunctional PSM light
10_Cayenne_21_KW17.book Seite 185 Donnerstag, 9. April 2009 3:33 15

186
Driving and Driving Safety Collapsible spare wheel
fNever switch the PSM off when driving with a
collapsible spare wheel.
To w i n g
fFor information on towing:
Please see the chapter “TOWING” on
Page 342.
Tip on driving
When PSM is switched off, wheel-specific brake
interventions and the traction control system
(TCS) are also inactive.
The automatic brake differential (ABD) remains on.
Switching PSM back onfPress PSM OFF button A.
PSM is switched on after a short delay.
The light-emitting diode in the button and the
multi-functional PSM light on the instrument
panel go out. A message is shown on the multi-
purpose display of the instrument panel.
ABS
(Anti-lock Brake System)
Warning!
In spite of the advantages of ABS, it is still the
driver’s responsibility to adapt her/his driving style
and maneuvers in line with road and weather
conditions, as well as the traffic situation.
The increased safety that is provided should not
induce you to take greater risks with your safety.
The limits set by the physics of driving cannot be
overcome, even with ABS.
Risks of accident due to inappropriate speed can-
not be reduced by ABS.
ABS ensures:
–Full steering control
The vehicle remains steerable
–Good driving stability
No skidding due to locked wheels
–Optimum braking distance
Shorter stopping distances in most cases
–Lock prevention
No flat spots on the tiresFunction
The decisive advantage of ABS is in the driving
stability and maneuvrability of the vehicle in
hazardous situations.
ABS prevents locking of the wheels during full
braking, on almost all road surfaces, until shortly
before the vehicle stops.
The ABS begins to control the braking process as
soon as a wheel shows a tendency to lock.
This controlled braking process is comparable to
extremely rapid cadence braking.
The pulsating brake pedal and a “rattling noise”
warn the driver to adapt her/his driving speed to
the road conditions.
fIf full braking should be necessary, press the
brake pedal all the way down throughout the
entire braking procedure, regardless of the
pulsating pedal. Do not ease up on pressure
applied to the pedal.
10_Cayenne_21_KW17.book Seite 186 Donnerstag, 9. April 2009 3:33 15