PORSCHE CAYNNE S 2005 1.G Owners Manual

Shifting Gear, Traction Systems
211
Driving Programs for On-Road and
Off-Road DrivingTwo different driving programs with special power-
transmission and running-gear control systems
(such as ABS, off-road ABS and PSM, etc.) are pro-
vided in your Porsche, with the aim of realising the
best possible driving dynamics combined with
maximum safety.
All control systems meet these requirements for
both off-road and normal driving.With rocker switch A, you can easily select the ap-
propriate driving program to suit the special re-
quirements for the respective terrain.
Off-road program Low Range
(with reduction)
When Low Range is active, the power transmis-
sion and running-gear control systems are
automatically adapted to the requirements for
off-road driving.
On-road driving program High Range
(without reduction)
When High Range is active, the power-transmis-
sion and running-gear control systems are auto-
matically adapted to the requirements for on-road
driving.
UseRocker switch A is located in the center console
of the vehicle. It features a multi-step function and
can be operated in both directions. Each time the rocker switch is pushed forward,
the vehicle becomes one step more suitable for
off-road driving. This is realised by changing from
the on-road to the off-road driving program or by
engaging the differential locks in stages.
The number of differential locks that can be en-
gaged in Low Range depends on the equipment of
your vehicle.
Each time the rocker switch is pushed back, the
vehicle becomes one step more suitable for on-
road driving.
Once the driving program has been selected, the
rocker switch springs back to home position.
Notes on operation
If the Low Range indicator light beside the rocker
switch flashes rapidly after the ignition is
switched on, there is a fault in the shifting
system.
fPlease have the vehicle checked immediately
at an authorized Porsche dealer.

212
Shifting Gear, Traction Systems If the Low Range indicator light beside the rocker
switch flashes when you attempt to operate rock-
er switch, the conditions for a shift have not been
met:
Vehicles with manual transmission
– Vehicle is not stationary.
– Brake is not pressed.
– Gear-shift lever is not in neutral.
Vehicles with Tiptronic S
– Vehicle has exceeded or gone below the limit
speed.
– Selector lever is not in position N.
A-Rocker switch
B- Low Range is engagedChanging from on-road driving program
to off-road driving programVehicles with manual transmission
fStop the vehicle.
fApply the brake.
fPut the gearshift lever in neutral.fPush rocker switch A forward until activation of
the off-road driving program is indicated on the
multi-purpose display of the instrument panel
and by illumination of light-emitting diodeB.
The Low Range indicator lights in the instru-
ment panel and beside the rocker switch flash
several times during the shifting process.
Low Range is now engaged.
Caution!
Risk of engine damage (overrevving). In the
Low Range program, the gear-changing
points are shifted towards lower engine-
speed ranges.
fShift early to prevent overrevving the engine.
Tip on driving
When Low Range is active, the power
transmission and running-gear control systems
are automatically adapted to the requirements for
off-road driving.
Low Range indicator light

Shifting Gear, Traction Systems
213
Vehicles with Tiptronic S
fReduce speed to below 9.3 mph (15 km / h) or
stop vehicle.
fMove selector lever to position N.
fPush rocker switch A forward until activation of
the off-road driving program is indicated on the
multi-purpose display of the instrument panel
and by illumination of light-emitting diodeB.
The Low Range indicator light on the instru-
ment panel and light-emitting diode B beside
the rocker switch flash several times during
the shifting process.
Low Range is now engaged.
Danger!
Serious risk of injury or death. Risk of
accident due to uncontrolled vehicle
movement. The selector lever is blocked
during the shifting procedure. Shifting when
driving uphill can cause the vehicle to stand
still or even roll backwards, if the shifting
procedure has not yet been completed.
When driving downhill, the vehicle can accel-
erate unintentionally while shifting.
fIncreased brake readiness is required.
fPlease observe the chapter “POWER-TRANS-
MISSION AND RUNNING-GEAR CONTROL SYS-
TEMS” on Page 217.
A- Rocker switch
B- Low Range is engaged
C- Center differential lock is fully engagedFully engaging the center differential lock
in Low RangeTip on driving
When the center differential lock is fully engaged,
there is no longer any speed difference between
the front and rear axles. If, for example, both
wheels at the front axle lose traction on an icy
road or soft surface, the rigidly linked drive wheels
will permit the vehicle to continue moving never-
theless.fPush rocker switch A forwards in stages until
engagement of the center differential lock is in-
dicated on the multi-purpose display of the in-
strument panel and by the illumination of the
two light-emitting diodes Band C.
The center differential lock is changed over to
fully engaged state by the automatic control
system.

214
Shifting Gear, Traction Systems
A- Rocker switch
B-Low Range is engaged
C- Center differential lock is fully engaged
D- Rear differential lock is fully engagedFully engaging the rear differential lock in
Low RangeTip on driving
When the rear differential lock is fully engaged,
there is no longer any speed difference between
the two rear wheels. If, for example, one drive
wheel at the rear axle loses traction on an icy road
or soft surface, the stiff through-drive function will
permit the car to continue moving nevertheless.fPush rocker switch A forwards in stages until
engagement of the rear differential lock (trans-
verse lock) is indicated on the multi-purpose
display of the instrument panel and by the
illumination of the three light-emitting diodes B,
Cand D.
The center and rear differential locks are chan-
ged over to fully engaged state by the auto-
matic control system.
Note on operation
The rear differential lock can only be engaged
while the engine is running.
Hydraulically disengageable anti-roll barsThe front and rear anti-roll bars can be disengaged
to improve traction and comfort when driving off
road. This feature increases the wheel articulation.
Condition for disengaging the anti-roll bars
– Low Range is engaged.
Note
The anti-roll bars cannot be engaged if the wheel
articulation or lateral acceleration is too great.

Shifting Gear, Traction Systems
215
Disengaging
fPress button E.
Disengagement of the anti-roll bars is indicated
on the multi-purpose display of the instrument
panel and by illumination of light-emitting diode
F.
The light-emitting diode on the button flashes
several times during the disengagement
process.
The anti-roll bars are disengaged.
Note on operation
The anti-roll bars cannot be disengaged manually
at speeds above 25 mph (40 km/h).
Engaging
fPress button E.
Light-emitting diode F on the button flashes
several times during the engagement
process and then goes out.
The anti-roll bars are engaged.Note on operation
The anti-roll bars are engaged automatically when
a speed of 30 mph (50 km/h) is exceeded or
when the lateral acceleration value is high.
Notes
Engagement of the anti-roll bars is audible.
At temperatures below –4°F (–20°C), the anti-roll
bars take somewhat longer to engage.Indication of a fault by:
– Continuous illumination of the light-emitting
diode in the button
– Illumination of the warning light on the
instrument panel
– A message on the multi-purpose display of the
instrument panel
fAdapt your driving behavior to the changed
conditions.
Drive slowly to the nearest authorized Porsche
dealer and have the fault remedied.
fPlease observe the chapter “WARNING LIGHTS
AND WARNING MESSAGES” on Page 108.
Indicator light and warnings

216
Shifting Gear, Traction Systems
Changing from off-road driving program
to on-road driving programVehicles with manual transmission
fStop the vehicle.
fApply the brake.
fPut the gearshift lever in neutral.
fPull rocker switch A back in stages until light-
emitting diodes B, C and if necessary, D are
out.
The Low Range indicator light on the instru-
ment panel and light-emitting diode B beside
the rocker switch flash several times during
the shifting process.
High Range is active.Vehicles with Tiptronic S
fReduce speed to below 19 mph (30 km / h) or
stop vehicle.
fMove selector lever to position N.
fPull rocker switch A back in stages until light-
emitting diodes B, C and if necessary, D are
out.
The Low Range indicator light on the instru-
ment panel and light-emitting diode B beside
the rocker switch flash several times during
the shifting process.
High Range is active.
Danger!
Serious risk of injury or death. Risk of
accident due to uncontrolled vehicle
movement. The selector lever is blocked
during the shifting procedure. Shifting when
driving uphill can cause the vehicle to stand
still or even roll backwards, if the shifting
procedure has not yet been completed.
When driving downhill, the vehicle can accel-
erate unintentionally while shifting.
fIncreased brake readiness is required.
fPlease observe the chapter “POWER-TRANS-
MISSION AND RUNNING-GEAR CONTROL SYS-
TEMS” on Page 217.

Shifting Gear, Traction Systems
217
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

218
Shifting Gear, Traction Systems
Porsche Traction Management (PTM)Porsche Traction Management is a full-time all-
wheel control system designed to influence the
longitudinal and lateral dynamics. It is closely
linked with the Porsche Stability Management
(PSM) system:
PTM ensures the best possible power distribution
to the four driven wheels at the front and rear ax-
les. The system realises this optimal traction by in-
tervening in the lock control function of the trans-
fer case and rear differential. PTM is active at all
times and, unlike the PSM, cannot be switched off.Advantages of PTM
– Obvious improvement in traction, driving stabil-
ity and steering ability of the car.
– Vehicle is more manageable when driven at its
performance limits.
– Improved straight-ahead tracking and stability.
– The aforementioned features allow for a sport-
ier setup of the running gear.
– The TCS and ABD provide even better traction
for all wheels.
Safety notes!
In spite of the advantages of PTM, 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 PTM.
Risks of accident due to inappropriate speed
cannot be reduced by PTM.

Shifting Gear, Traction Systems
219
Full-time all-wheel drive
With the four-wheel drive, the drive power is vari-
ably 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.
Safety notes!
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.

220
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).
Safety notes!
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 (Ferraria effect) when the driver
releases the accelerator pedal or brakes on
bends. 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
bends).
– Improved braking stability on bends and on dif-
ferent 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.