2006 PORSCHE CAYENNE TURBO engine

Shifting Gear, Traction Systems
227
Power-Transmission and Running-Gear Control SystemsA complex interconnection of all control systems acting in power transmission and in the running gear has been realised in your Porsche.
All control systems have been linked with the aim of combining the best possible driving performance with maximum safety.
The following systems are involved:
System/designation Scope
PTM
Porsche Traction Management– Full-time all-wheel drive
– Electronically controlled center differential lock
– Automatic brake differential (ABD)
– Traction control system (TCS)
– Reduction gear/Low Range
PTM Plus
Porsche Traction ManagementIn addition to the PTM features, PTM Plus also includes:
– Electronically controlled rear differential lock
– Hydraulically disengageable anti-roll bars
PSM
Porsche Stability Management– Stability management system
– Anti-lock brake system (ABS)
– Traction control system (TCS)
– Automatic brake differential (ABD)
– Engine drag torque control (MSR)
Air suspension
with level control and height adjustment– Fully load bearing air spring struts with integral shock absorbers
– Air supply system with pressure accumulator
PAS M
Porsche Active Suspension Management– Shock absorber system with adaptive, continuous shock absorber control

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229
Full-time all-wheel drive
With the four-wheel drive, the drive power is varia-
bly distributed to the front and rear wheels.
Power distribution and wheel speed compensation
between the front and rear axles is realised with a
transfer box.
Distribution of the drive power depends on the
wheel speed difference between the two axles.
The transfer box always controls power distribu-
tion in such a way that optimal propulsion is
achieved, even on an unfavorable road surface.
Full-time four-wheel drive ensures optimal handling
and great stability.
Warning!
In spite of the advantages of four-wheel drive, it is
still the driver’s responsibility to adapt 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 in-
duce you to take greater risks with your safety.
The limits set by the physics of driving cannot be
overcome, even with four-wheel drive.
Risks of accident due to inappropriate speed can-
not be reduced by four-wheel drive.Automatic brake differential (ABD)
The ABD system controls the front and rear axles
separately. If one wheel of an axle starts to spin,
it is braked so that the other wheel on the same
axle can be driven.
The ABD recognises different driving states, and it
features control strategies adapted to these
states. In situations in which little propulsive power
is required, such as when the car moves off on a
level gravel surface, traction control already be-
comes active at low engine speeds. If great
propulsive power is required, e.g. when moving off
on an uphill slope or for rapid acceleration, the
ABD is adapted accordingly.
A special off-road program is used in Low Range
mode.Traction control system (TCS)
The traction control system prevents the wheels
from spinning by adjusting the engine power,
thereby ensuring good lane-holding ability and a
stable driving behavior.

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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.

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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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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

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Shifting Gear, Traction Systems Off-road ABS
(ABS in Low Range program)
When Low Range is active, an ABS specially
matched to off-road driving is activated automati-
cally.
At speeds below 30 mph (50 km/h), the front
wheels can lock up in cycles during braking to
shorten the braking distance when the vehicle is
driven off-road (the wheels dig in to the surface).
If the driver needs to steer, this off-road driving
program is automatically switched off briefly to
maintain steerability.
HillholderIn 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
running. The driver does not have to apply the
brake.
The hillholder thus makes moving off on slopes
easier.
Danger!
Risk of accident.
The vehicle can roll backwards if the Hillhold-
er is switched off.
fAlways apply the footbrake on slopes.
Hillholder is not active:
– In selector lever positions N and R
– In the reduced driving program and
– If not all of the wheels are touching the ground
(on difficult terrain, for example).
Warning!
In spite of the advantages of the hillholder func-
tion, it is still the driver’s responsibility to adapt his
driving style and maneuvers in line with situational
conditions.
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 the hillholder function.
Driving at the limits should be avoided, e.g., on icy
slopes or on slippery surfaces. In this and similar
cases, the support of the hillholder function is not
ensured.

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235
Engine Braking Support
(Assistance when heading downhill)The Porsche Down-Hill Assistant is an assistance
system which helps the driver at slower downhill
driving up to approx. 12 mph (20 km/h), e.g., on
steep slopes or on wintry mountain roads.
As long as the accelerator pedal is not used when
traveling downhill, the Porsche Down-Hill Assistant
is active and brakes the vehicle.
The braking ability of the Engine Braking Support
is affected by slippery surfaces (e.g., on icy or
loose surfaces), like all brakes.
If road grip is lost on one or more wheels, the
system brakes the wheels which have good road
contact.
Warning!
Risk of accident. Reduced braking ability on
a slippery surface.
fAlways adjust your driving style to the driving situationConditions:
– The gas pedal must not be used when
travelling downhill.
– The speed must not
exceed 12 mph (20 km/h).
– The selector lever position D, M or R must be
engaged.
Tip on driving
The Porsche Down-Hill Assistant is active when
driving downhill either forwards or backwards.
Checks on test standsPower measurement
Power measurements on roller test stands are not
approved by Porsche.
Brake tests
Brake tests must be carried out only in High Range
and on plate-type test stands or roller test stands.
The following limit values must not be exceeded
on roller test stands:
– Testing speed 4.7 mph (7.5 km/h)
– Test duration 20 seconds
Parking brake test
Parking brake tests on the brake tester must be
performed only with the ignition switched off and
the selector lever in position N.Balancing wheels on the vehicle
During finish balancing of the wheels, the entire ve-
hicle must be lifted and the wheels must be free to
turn.
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 driv-
ing axle of the vehicle, rotates to simulate vehicle
operation on the road while the vehicle remains
stationary.
Your Porsche Cayenne has a full-time four-wheel
drive system which cannot be disabled. Severe
d a m a g e t o t h e p o w e r t r a i n c a n re s u l t i f t e s t e d o n a
two-wheel dynamometer.
Warning!
To avoid severe powertrain damage and a
possible unexpected movement of the vehi-
cle.
fYour Porsche Cayenne vehicle must never be
tested on a two-wheel dynamometer.
fAdvise the emission station of this warning be-fore testing the vehicle.

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Shifting Gear, Traction Systems
Off-Road DrivingfPlease read this chapter carefully before driv-
ing off road with your Porsche.
The information provided will familiarise you with
the special advantages of your vehicle, allowing
you to arrive at your destination safely every time.
We recommend practicing on less rugged terrain.
Vehicles with SportDesign package
Caution!
Risk of damage. On vehicles with
SportDesign package, front, rear, and side
member trim are painted and pulled down
lower. Off-road driving can seriously damage
these trim parts.
fWhen driving off-road, make sure these parts
are not damaged.
fMake sure there is sufficient clearance
between obstacles and the underside of the
vehicle.
fAvoid driving through water.
fDo not use side member trim as a running board.Maintenance note
Please bear in mind that off-road driving subjects
all vehicle components to considerably more wear
than normal use, making professional inspection
and maintenance after each use a vital precondi-
tion for functioning and safety.
Grains of sand, dirt particles and other abrasive
materials entering the brakes can cause exces-
sive wear or unpredictable braking action.
Rules for off-road drivingfEnsure vehicle is equipped with approved all-
terrain tires.
fPlease observe the chapter “GROUND CLEA-
RANCE” on Page 375.
fActivate Low Range.
fStow or fasten luggage and loads securely.
Please observe the chapter “LOADING INFOR-
MATION” on Page 207.
fIf unknown terrain is obscured from view, ex-
amine it on foot first and traverse it with ex-
treme caution.
This way, obstacles are easier to recognise
and damage to the vehicle is avoided.fAlways drive with the engine running.
Steering assistance is provided only with the
engine running.
fDrive slowly and uniformly.
fAlways make sure that the wheels touch the
ground.
fBefore driving through water, check the water
depth, the condition of the surface beneath it
and the speed of the water.
fLook out for obstacles such as boulders,
holes, tree stumps or ruts.
fAlways keep the sliding/lifting roof or
Panorama roof system and the side windows
closed while driving.
fDo not depart from marked routes or paths.
fRespect nature.
Always obey off-limits signs.