2006 PORSCHE CAYENNE TURBO traction control

230
Shifting Gear, Traction Systems
Porsche Stability Management (PSM)PSM is an active control system for stabilisation of
the vehicle during extreme driving maneuvres. It
operates together with the Porsche Traction
Management (PTM) system.
PSM makes use of both the ABD and TCS sys-
tems, as well as the known functions of the anti-
lock brake system (ABS) and engine drag torque
control system (MSR).
Warning!
In spite of the advantages of PSM, it is still the driv-
er’s responsibility to adapt his driving style and
maneuvres in line with road and weather condi-
tions, as well as the traffic situation.
The increased safety that is provided should not in-
duce you to take greater risks with your safety.
The limits set by the physics of driving cannot be
overcome, even with PSM.
Risks of accident due to inappropriate speed
cannot be reduced by PSM.Advantages of PSM
– Best possible traction and lane-holding ability
in all driving situations – even on road surfaces
with varying friction.
– The system compensates for undesired vehi-
cle reactions (load-alteration effect) when the
driver releases the accelerator pedal or brakes
on corners. This compensation functions up to
the maximum lateral acceleration.
– PSM actively stabilises the vehicle in the event
of under and oversteering during dynamic
driving maneuvres (e.g. rapid steering move-
ments, during lane changes or on alternating
corners).
– Improved braking stability on corners and on
different or varying road surfaces.Readiness for operation
PSM is switched on automatically every time you
start the engine.
Function
Sensors at the wheels, brakes, steering system
and engine continuously measure:
–Driving speed
– Direction of travel
– Lateral acceleration
– Longitudinal acceleration
– Rate of turn about the vertical axis
PSM uses these values to determine the direction
of travel desired by the driver.
PSM intervenes and corrects the course if the ac-
tual direction of motion deviates from the desired
course (steering-wheel position):
It brakes individual wheels as needed. If neces-
sary, PSM additionally influences the engine power
or the gear-changing characteristic of the Tiptron-
ic in order to stabilise the vehicle.

Shifting Gear, Traction Systems
231
The events below inform the driver of PSM control
operations and warn him to adapt his driving style
to the road conditions:
– The information light in the instrument panel
lights up.
– 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.
However, it is possible at any time to achieve
full vehicle deceleration by increasing the foot
pressure slightly.
Examples of PSM control operations
–Vehicle understeers:
If the front wheels of the vehicle drift on a cor-
ner, engine power is reduced and the rear
wheel on the inside of the corner is braked if
necessary.
–Vehicle oversteers:
If the rear of the vehicle swings out on a cor-
ner, the front wheel on the outside of the cor-
ner is braked.Combined use of PSM and PTM/PTM Plus
In order to ensure optimal stabilisation of the
vehicle, the center differential lock (PTM) and
possibly the rear differential lock (PTM Plus) are
also opened when PSM interventions occur.
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.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.
At a speed below 22 mph (35 km/h), the terrain
PSM intervenes later if the vehicle should unders-
teer and thereby improves steerability in Low
Range.
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 overrunning. This
is also the case for downshifts on a slippery road.

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Shifting Gear, Traction Systems
Switching off PSMfPress PSM OFF button A.
PSM is switched off after a short delay.
The light-emitting diode in the button lights up.
When the PSM is switched off, the multifunc-
tional PSM light on the instrument panel is lit
and a message appears in the multi-purpose
display of the instrument panel.
During braking, the vehicle is stabilised 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.
H o w e v e r, i t c a n b e o f a d v a n t a g e t o s w i t c h o f f P S M
temporarily in exceptional situations:
– On a loose surface or in deep snow
– When “rocking the vehicle free”
– When using snow chains.
When the PSM is switched off the slip monitoring
function of the Tiptronic is also deactivated.
– The multifunctional light on the instrument
panel lights up for a lamp check when the
ignition is switched on.
– The light indicates a control operation,
including when PSM is switched off (brake
control in the event of one-sided wheel spin).
– Faults are displayed by the light in conjunction
with the multi-purpose display of the instru-
ment panel.
PSM is out of order.
Consult your authorized Porsche dealer.Collapsible spare wheel
fNever switch the PSM off when driving with a
collapsible spare wheel.
To w i n g
fPlease observe the chapter “TOWING” on
Page 360.
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.
Switching PSM back onfPress PSm OFF button A.
PSM is switched on after a short delay.
Multifunctional PSM light

Shifting Gear, Traction Systems
233
ABS
(Anti-lock Brake System)
Warning!
In spite of the advantages of ABS, it is still the driv-
er’s responsibility to adapt his driving style and
maneuvres in line with road and weather condi-
tions, as well as the traffic situation.
The increased safety that is provided should not in-
duce 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, even during heavy braking
while cornering.
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 his driving speed to the
road conditions.Warning light
If the ABS warning lights light up in the instrument
panel and on the multi-purpose display of the in-
strument panel while the engine is running, the
ABS has switched off because of a fault.
In this event, the braking system will operate with-
out lock prevention,as in cars without ABS.
fAdapt your driving style to the changed brak-
ing behavior.
fThe ABS must be checked immediately at an
authorized Porsche dealer. This is necessary
in order to prevent the occurrence of further
faults whose effects cannot be defined.
The ABS control unit is adjusted for the approved
tire dimensions.
The use of tires with non-approved dimensions can
lead to different wheel speeds, causing the ABS to
switch off.
f f f

Shifting Gear, Traction Systems
237
Driving systems for off-road drivingSpecially adapted driving programs or power-
transmission and running-gear control systems
are available for off-road driving:
– Off-road program Low Range
–Off-road PSM
–Off-road ABS
– Center differential lock
– Rear differential lock
fPlease observe the chapter “POWER-TRANS-
MISSION AND RUNNING-GEAR CONTROL SYS-
TEMS” on Page 227.Before driving offTires
fCheck tread depth and tire pressure.
fCheck for damage and remove any foreign ob-
jects (e.g. stones) from the tread.
fReplace missing valve caps.
Rims
fReplace dented or damaged rims before
driving off road.
After driving off roadOff-road driving places a greater burden on the ve-
hicle than does normal driving on roads.
We recommend inspecting the vehicle after off-
road driving. Potential damage poses an accident
risk and impairs driving comfort. Damage on the
car is recognised in good time if the car is
checked.
Warning!
Car damage poses an accident risk for the
vehicle occupants and other road users.
fIn cases of doubt, have your vehicle checked
by your authorized Porsche dealer.
fExamine tires for signs of damage such as
cuts, tears, bulges or foreign objects stuck in
the tread. Replace a damaged tire if neces-
sary.
fHave any damage to your vehicle repaired by an authorized Porsche dealer without delay.
Recommended procedure
fDeactivate Low Range.
fClean headlights and tail lights and check them
for signs of damage.
fClean the front and rear license plates.fClean the tire tread with a jet of water and re-
move any foreign objects.
fClean wheels, wheel housings and the under-
body with a jet of water.
fCheck whether the car has picked up plant
parts or branches.
These materials increase the risk of fire and
can damage fuel lines, brake hoses, boots of
the axle joints and drive shafts.
fAfter off-road driving, always check the entire
floor assembly, tires, body structure, steering
system, running gear and exhaust system for
signs of damage.
fAfter driving for an extended period through
mud, sand, water or substances with a similar
soiling effect, check the brake discs, brake
pads, wheels and axle joints and have them
cleaned.
fIf you experience severe vibrations after
driving off road, check the wheels for foreign
substances.
These substances can produce an imbalance
which might be responsible for the vibrations.
Removing these deposits may remedy the
problem.

240
Shifting Gear, Traction Systems
Water crossingfPlease observe the chapter “GROUND CLEA-
RANCE” on Page 375.
Danger!
Danger of drowning if water enters the vehi-
cle. Risk of damage to the engine and acces-
sories if water penetrates.
fBefore driving through water, check the water
depth A, water speed and the condition of the
surface beneath it.
The water must not be deeper than 20 in.
(50 cm). The water must not be deeper than
22 in. (55.5 cm) for vehicles with level control
and height adjustment.
fCheck the door sills and rubber seals before
starting to drive.
fDo not drive through deep or rapidly flowing
water.
Deep or rapidly flowing water, e.g. mountain
streams, can cause the car to deviate from the
intended path.
fAvoid a "bow wave" by driving at an appropriate
speed.
fNever open the doors when driving through wa-
ter.Soiling can impair the braking action.
fCheck and clean the brakes if they have been
soiled.
Danger of steering assistance failing during
a long journey in the water if the drive belt
slips.
fIf the steering assistance fails, more effort will
be required to steer.
Danger of damaging electrical systems
fAvoid driving through salt water.
Notes on operation
fActivate Low Range.
fSwitch the air conditioner off.
fSwitch the headlights off.

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Shifting Gear, Traction Systems
Air Suspension with Level Control
and Height AdjustmentOn vehicles with air suspension, the driver can set
five different level steps manually.
The preselected level is automatically adjusted to
suit the vehicle speed.
The height of the car is automatically kept
constant when the car is loaded.
Tip on driving
It is not permissible to drive on public roads with
the car in the terrain or special terrain setting.Note on operation
Frequent level changes can cause the compressor
to overheat. In this case, the compressor must
cool for several minutes before the level adjust-
ment is fully functional again.
Normal levelThe ground clearance at normal level is around
8.5 in or 217 mm.Terrain levelThis setting is intended for off-road driving, field
paths and forest paths, etc.
The vehicle is raised by around 1 in or 26 mm.
compared to normal level.
Terrain level can be selected only manually at
speeds below around 50 mph (80 km/h).
The car is automatically lowered to normal level at
speeds exeeding around 50 mph (80 km/h).
The car is automatically raised to terrain level
when Low Range is activated.
Special terrain levelThis setting is intended only for extremely chal-
lenging terrain requiring maximum ground clear-
ance. The vehicle is raised by 2.2 in or 56 mm
compared to normal level.
The warning light in the instrument panel comes
on when the special terrain level has been
reached.
Special terrain level can be selected only at
speeds below around 19 mph (30 km/h).
The car is automatically lowered to terrain level at
speeds exeeding around 19 mph (30 km/h).Low levelThis level is intended for high-speed driving. Above
speeds of around 78 mph (125 km/h), the car is
lowered by around 1 in or 27 mm compared to
normal level.
When the speed drops to below around 25 mph
(40 km/h), the car is automatically raised to nor-
mal level.Special low levelAt extremely high speeds, for example when oper-
ated on a race track, the car is lowered 0.4 in or
11 mm compared to the low level.

Shifting Gear, Traction Systems
245
Loading level
Caution!
Risk of damage to running-gear parts, units
and the vehicle underbody.
If the car is driven off a curb when at loading level,
for example, insufficent ground clearance can
cause it to bottom out.
fAlways switch to normal level before moving off.
This setting makes it easier for you to load the lug-
gage compartment.
The vehicle is lowered by around 2.4 in. or 60 mm
compared to normal level.
The car is automatically raised to normal level at
speeds exceeding around 3 mph (5 km/h).
Setting level manuallyPreconditions
–Ignition on.
– Doors are closed.
Setting
fMove rocker switch in the appropriate direc-
tion.
This sets the next possible height.
Indication of selected level
The corresponding light-emitting diode beside the
rocker switch flashes during the control process.
The light-emitting diode is continuously lit after the
control process.
The level change is also indicated on the multi-pur-
pose display of the instrument panel.
Exceptions
Automatic changes from normal level to low level
and back are not indicated on the multi-purpose
display of the instrument panel.
Note on operation
The level selected last is stored in memory after
the ignition is switched off.Raising the vehicle
1st actuation: Terrain level
2nd actuation: Special terrain level
f f f