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Porsche Cayenne (2010 year). Manual - part 11

Power-Transmission and Running-Gear Control Systems

A complex interconnection of all control systems acting in power transmission and in the running gear has been realized 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

- Full-time all-wheel drive

Porsche Traction Management

- Electronically controlled center differential lock

- Automatic brake differential (ABD)

- Traction control system (TCS)

- Reduction gear/Low Range

PTM Plus

In addition to the PTM features, PTM Plus also includes:

Porsche Traction Management

- Electronically controlled rear differential lock

PSM

- Stability management system

Porsche Stability Management

- Anti-lock brake system (ABS)

- Brake system prefilling

- Brake booster

- Traction control system (TCS)

- Automatic brake differential (ABD)

- Engine drag torque control (MSR)

Air suspension

- Fully load bearing air spring struts with integral shock absorbers

with level control and height adjustment

- Air supply system with pressure accumulator

PASM

- Shock absorber system with adaptive, continuous shock absorber control

Porsche Active Suspension Management

PDCC

- Active chassis control system to stabilize roll tendency of vehicle body when driving

Porsche Dynamic Chassis Control

Driving and Driving Safety

181

Warning!

Advantages of PTM

Automatic brake differential (ABD)

In spite of the advantages of PTM or four-wheel dri-

- Obvious improvement in traction, driving

The ABD system controls the front and rear axles

ve, it is still the driver’s responsibility to adapt her/

stability and steering ability of the car.

separately. If one wheel of an axle starts to spin,

his driving style and maneuvers in line with road

it is braked so that the other wheel on the same

- Vehicle is more manageable when driven at its

and weather conditions, as well as the traffic situ-

axle can be driven.

performance limits.

ation.

The ABD recognizes different driving states, and it

- Improved straight-ahead tracking and stability.

The increased safety that is provided should not

features control strategies adapted to these

induce you to take greater risks with your safety.

- The aforementioned features allow for a

states. In situations in which little propulsive power

The limits set by the physics of driving cannot be

sportier setup of the running gear.

is required, such as when the car moves off on a

overcome, even with PTM or four-wheel drive.

level gravel surface, traction control already

- The TCS and ABD provide even better traction

becomes active at low engine speeds. If great

Risks of accident due to inappropriate speed

for all wheels.

propulsive power is required, e.g. when moving off

cannot be reduced by PTM.

on an uphill slope or for rapid acceleration, the

Full-time all-wheel drive

ABD is adapted accordingly.

With the four-wheel drive, the drive power is

A special off-road program is used in Low Range

Porsche Traction Management (PTM)

variably distributed to the front and rear wheels.

mode.

Power distribution and wheel speed compensation

Porsche Traction Management is a full-time all-

between the front and rear axles is realized with a

Traction control system (TCS)

wheel control system designed to influence the

transfer box.

longitudinal and lateral dynamics. It is closely

The traction control system prevents the wheels

linked with the Porsche Stability Management

Distribution of the drive power depends on the

from spinning by adjusting the engine power,

(PSM) system:

wheel speed difference between the two axles.

thereby ensuring good lane-holding ability and a

The transfer box always controls power distribu-

stable driving behavior.

PTM ensures the best possible power distribution

tion in such a way that optimal propulsion is achie-

to the four driven wheels at the front and rear

ved, even on an unfavorable road surface.

axles. The system realizes this optimal traction by

intervening in the lock control function of the trans-

Full-time four-wheel drive ensures optimal handling

fer case and rear differential. PTM is active at all

and greater stability.

times and, unlike the PSM, cannot be switched off.

182 Driving and Driving Safety

Porsche Stability Management (PSM)

Advantages of PSM

Readiness for operation

-

Best possible traction and lane-holding ability

PSM is switched on automatically every time you

PSM is an active control system for stabilization of

in all driving situations - even on road surfaces

start the engine.

the vehicle during extreme driving maneuvers. It

with varying friction.

operates together with the Porsche Traction

Function

Management (PTM) system.

-

The system compensates for undesired vehi-

cle reactions (load-alteration effect) when the

Sensors at the wheels, brakes, steering system

PSM makes use of both the ABD and TCS

and engine continuously measure:

driver releases the accelerator pedal or brakes

systems, as well as the known functions of the

on bends. This compensation functions up to

- Driving speed

anti-lock brake system (ABS) and engine drag

the maximum lateral acceleration.

torque control system (MSR).

- Direction of travel (steering angle)

-

PSM actively stabilizes the vehicle as required

Warning!

during dynamic driving maneuvers (e.g. rapid

- Lateral acceleration

steering movements, during lane changes or

- Longitudinal acceleration

In spite of the advantages of PSM, it is still the

on alternating bends).

driver’s responsibility to adapt her/his driving style

- Rate of turn about the vertical axis

and maneuvers in line with road and weather

-

Improved braking stability on corners and on

different or varying road surfaces.

PSM uses these values to determine the direction

conditions, as well as the traffic situation.

of travel desired by the driver.

-

Improved brake functioning and reduced

The increased safety that is provided should not

PSM intervenes and corrects the course if the

induce you to take greater risks with your safety.

stopping distance in the event of emergency

actual direction of motion deviates from the

The limits set by the physics of driving cannot be

braking.

desired course (steering-wheel position):

overcome, even with PSM.

It brakes individual wheels as needed. If neces-

Risks of accident due to inappropriate speed

sary, PSM additionally influences the engine power

cannot be reduced by PSM.

or the gear-changing characteristic of the

Tiptronic in order to stabilize the vehicle.

Driving and Driving Safety

183

During braking, the vehicle is stabilized even

Multifunctional PSM light

when PSM is switched off.

One-sided spinning of the wheels is prevented,

-

The multifunctional light on the instrument pa-

even with PSM switched off.

nel lights up for a lamp check when the ignition

is switched on.

PSM should always be switched on during

“normal” driving.

-

The light indicates a control operation, inclu-

However, it can be of advantage to switch off PSM

ding when PSM is switched off (brake control

temporarily in exceptional situations:

in the event of one-sided wheel spin).

- On a loose surface or in deep snow

-

In conjunction with the multi-purpose display on

the instrument panel, the light indicates that

- When “rocking the vehicle free”

PSM is switched off.

- When using snow chains.

-

Faults are displayed by the light in conjunction

Vehicles with Tiptronic: When the PSM is

with the multi-purpose display of the instru-

switched off the slip monitoring function is also

ment panel.

deactivated.

PSM is out of order.

f

Consult your authorized Porsche dealer.

Switching off PSM

f Press 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.

Driving and Driving Safety

185

Collapsible spare wheel

ABS

Function

(Anti-lock Brake System)

f Never switch the PSM off when driving with a

The decisive advantage of ABS is in the driving

collapsible spare wheel.

stability and maneuvrability of the vehicle in

Warning!

hazardous situations.

Towing

In spite of the advantages of ABS, it is still the

ABS prevents locking of the wheels during full

f For information on towing:

driver’s responsibility to adapt her/his driving style

braking, on almost all road surfaces, until shortly

Please see the chapter “TOWING” on

and maneuvers in line with road and weather

before the vehicle stops.

Page 342.

conditions, as well as the traffic situation.

The ABS begins to control the braking process as

The increased safety that is provided should not

Tip on driving

soon as a wheel shows a tendency to lock.

induce you to take greater risks with your safety.

This controlled braking process is comparable to

When PSM is switched off, wheel-specific brake

The limits set by the physics of driving cannot be

extremely rapid cadence braking.

interventions and the traction control system

overcome, even with ABS.

The pulsating brake pedal and a “rattling noise”

(TCS) are also inactive.

Risks of accident due to inappropriate speed can-

warn the driver to adapt her/his driving speed to

The automatic brake differential (ABD) remains on.

not be reduced by ABS.

the road conditions.

f If full braking should be necessary, press the

Switching PSM back on

ABS ensures:

brake pedal all the way down throughout the

- Full steering control

entire braking procedure, regardless of the

f Press PSM OFF button A.

The vehicle remains steerable

pulsating pedal. Do not ease up on pressure

PSM is switched on after a short delay.

The light-emitting diode in the button and the

applied to the pedal.

- Good driving stability

multi-functional PSM light on the instrument

No skidding due to locked wheels

panel go out. A message is shown on the multi-

- Optimum braking distance

purpose display of the instrument panel.

Shorter stopping distances in most cases

- Lock prevention

No flat spots on the tires

186 Driving and Driving Safety

Warning light

In the event of braking on loose ground, the per-

Hillholder is not active:

missible slip values for ABS braking are increased

If the ABS warning lights light up in the instrument

- In Tiptronic selector lever positions N and R

so that the off-road braking distance is reduced

panel and on the multi-purpose display of the

(wheels dig into the surface).

- In the limp-home mode and

instrument panel while the engine is running, the

If the driver needs to steer, this off-road driving

ABS has switched off because of a fault.

- If not all of the wheels are touching the ground

program is automatically switched off to maintain

In this event, the braking system will operate with-

(on difficult terrain, for example).

steerability.

out lock prevention,as in cars without ABS.

Warning!

f Adapt your driving style to the changed

Hillholder -

braking behavior.

In spite of the advantages of the hillholder func-

moving-off assistant on vehicles with

tion, it is still the driver’s responsibility to adapt

f The ABS must be checked immediately at an

Tiptronic S

her/his driving style and maneuvers in line with

authorized Porsche dealer. This is necessary

In Tiptronic selector lever positions D and M, the

situational conditions.

in order to prevent the occurrence of further

hillholder function makes it easier to move off

The increased safety that is provided should not

faults whose effects cannot be defined.

from a standstill on an upward slope when the

induce you to take greater risks with your safety.

The ABS control unit is adjusted for the approved

engine is running. The driver does not have to

The limits set by the physics of driving cannot be

tire dimensions.

apply the brake.

overcome, even with the hillholder function.

The use of tires with non-approved dimensions can

Driving at the limits should be avoided, e.g., on icy

lead to different wheel speeds, causing the ABS to

The hillholder thus makes moving off on slopes

slopes or on slippery surfaces. In this and similar

easier.

switch off.

cases, the support of the hillholder function is not

guaranteed.

Off-road ABS

Danger!

(ABS in Low Range program)

Risk of accident, resulting in serious perso-

When Low Range is active, an ABS specially

nal injury or death.

matched to off-road driving is activated automati-

The vehicle can roll backwards if the Hillhol-

cally.

der is switched off.

f Always apply the footbrake on slopes.

Driving and Driving Safety

187

Porsche Drive-Off Assistant -

Moving off with Porsche Drive-Off Assistant

Note on operation

Moving-off assistant on vehicles with

1.

Hold the vehicle securely with footbrake or

The Porsche Drive-Off Assistant ceases to func-

manual transmission

parking brake on the slope.

tion:

The engine must be running.

The Porsche Drive-Off Assistant enables the driver

- By shifting to neutral.

to move off on upward slopes. The vehicle must

2.

Fully depress the clutch pedal.

- When changing gears.

have sufficient road contact to use this feature.

3.

Engage one of the gears used to ascend in the

- If the engine is not running.

The Porsche Drive-Off Assistant is available for

direction of travel (1st gear or reverse).

slopes starting at approximately 5%.

4.

While keeping the clutch pedal depressed,

Danger!

f Please see the chapter “TRAILER COUPLING”

release the footbrake or foot-operated parking

Risk of accident, resulting in serious perso-

on Page 230.

brake.

nal injury or death.

The vehicle is held on the slope.

If the Porsche Drive-Off Assistant ceases to

Danger!

5.

Move off as usual.

function, the vehicle will no longer be held on

Risk of accident, resulting in serious perso-

a slope.

nal injury or death.

f Hold the vehicle with the footbrake.

When moving off on a slippery surface (e.g.,

on icy or loose surfaces), assistance by the

Porsche Drive-Off Assistant is no longer

assured. In this case, the vehicle could slip.

The limits set by the physics of driving cannot

be overcome, even with the Porsche Drive-

Off Assistant. The responsibility for moving

off on upward slopes is still the driver's,

despite the Porsche Drive-Off Assistant.

f Always adjust your driving style to the driving

conditions and vehicle load, use the footbrake

if necessary.

188 Driving and Driving Safety

Engine Braking Support

- Vehicles with Tiptronic S:

Balancing wheels on the vehicle

(Assistance when heading downhill)

The Tiptronic selector lever position D, M or R

During finish balancing of the wheels, the entire

must be engaged.

vehicle must be lifted and the wheels must be free

The Porsche Down-Hill Assistant is an assistance

- Vehicles with manual transmission:

to turn.

system which helps the driver at slower downhill

The reverse gear or any other gear (1. - 6. )

driving up to approx. 12 mph (20 km/h), e.g., on

must be engaged. The clutch pedal must not

steep slopes or on wintry mountain roads.

Dynamometer testing procedure

be used when travelling downhill.

As long as the gas pedal is not used when

Some U.S. states and Canadian provinces con-

traveling downhill, the Porsche Down-Hill Assistant

Tip on driving

duct emissions inspection/maintenance testing

is active and brakes the vehicle.

involving the use of two-wheel dynamometer.

The Porsche Down-Hill Assistant is active when

If road grip is lost on one or more wheels, the

driving downhill either forwards or backwards.

A two-wheeled dynamometer is a treadmill type

device upon which a single axle of the car, the dri-

system brakes the wheels which have good road

ving axle of the vehicle, rotates to simulate vehicle

contact.

Checks on test stands

operation on the road while the vehicle remains

The braking ability of the Engine Braking Support

stationary.

Brake tests

is affected by slippery surfaces (e.g., on icy or

Your Porsche Cayenne has a full-time four-wheel

loose surfaces), like all brakes.

Brake tests must be carried out only in High Range

drive system which cannot be disabled. Severe

and on plate-type test stands or roller test stands.

damage to the powertrain can result if tested on a

Warning!

The following limit values must not be exceeded

two-wheel dynamometer.

Risk of accident, resulting in serious perso-

on roller test stands:

nal injury or death. Reduced braking ability

- Testing speed 4.7 mph (7.5 km/h)

Warning!

on a slippery surface.

- Test duration 20 seconds

To avoid severe powertrain damage and a

f Always adjust your driving style to the driving

possible unexpected movement of the vehic-

situation.

Parking brake test

le.

Parking brake tests on the brake tester must be

f Your Porsche Cayenne vehicle must never be

Conditions:

performed only with the ignition switched off and

tested on a two-wheel dynamometer.

- The gas pedal must not be used when

the Tiptronic selector lever in position N or the

f Advise the emission station of this warning

travelling downhill.

gearshift lever in neutral.

before testing the vehicle.

- The speed must not exceed 12 mph

(20 km/h).

Driving and Driving Safety

189

Note on operation

Special terrain level

Frequent level changes can cause the compressor

This setting is intended only for extremely

to overheat. In this case, the compressor must

challenging terrain requiring maximum ground

cool for several minutes before level adjustment is

clearance. The vehicle is raised by around 2.2 in.

fully functional again.

(56 mm) compared to normal level.

The warning light

in the instrument panel

Normal level

comes up when the special terrain level has been

The ground clearance at normal level is around

reached.

8.5 in. (215 mm) (Cayenne, Cayenne S,

Special terrain level can be selected only at

Cayenne S Transsyberia) or 7.68 in (195 mm)

speeds below around 19 mph (30 km/h).

(Cayenne GTS).

The car is automatically lowered to terrain level at

speeds exceeding approx. 19 mph (30 km/h).

Terrain level

This setting is intended for off-road driving, field

Low level

paths and forest paths, etc.

The vehicle is raised by around 1 in. (26 mm)

This level is intended for high-speed driving. Above

Air Suspension with Level Control

compared to normal level.

speeds of around 78 mph (125 km/h), the car is

and Height Adjustment

automatically lowered by around 1 in. (24 mm)

Terrain level can be selected only manually at

(Cayenne, Cayenne S, Cayenne S Transsyberia) or

On vehicles with air suspension, the driver can set

speeds below around 50 mph (80 km/h).

0.4 in. (9 mm) (Cayenne GTS) compared to

five different level steps manually.

The car is automatically lowered to normal level at

normal level.

The preselected level is automatically adjusted to

speeds exceeding around 50 mph (80 km/h).

When the speed drops to below around 25 mph

suit the vehicle speed.

The car is automatically raised to terrain level

(40 km/h), the car is automatically raised to

The height of the car is automatically kept

when Low Range is activated.

normal level.

constant when the vehicle is loaded.

Note

Tip on driving

If low level was set manually with the rocker switch

It is not permissible to drive on public roads with

in the center console, low level also remains

the car in the terrain or special terrain setting.

active at speeds below around 25 mph (40 km/h).

190 Driving and Driving Safety

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, insufficient ground clearance can

cause it to bottom out.

f Always switch to normal level before moving

off.

This setting makes it easier for you to load the

luggage compartment.

The car is lowered by around 2.1 in. (54 mm)

(Cayenne, Cayenne S, Cayenne S Transsyberia) or

1.3 in. (34 mm) (Cayenne GTS) compared to

normal level.

Setting level manually

A - Special terrain level

The car is automatically raised to normal level at

B - Terrain level

speeds exceeding around 3 mph (5 km/h).

C - Normal level

Preconditions

D - Low level

- Ignition on.

E - Loading level

- Doors are closed.

Raising the vehicle

Note on operation

f Briefly press rocker switch forward

The car is raised one level.

The level last selected is stored in the memory

after the ignition is switched off.

Lowering the vehicle

f Briefly pull rocker switch to the rear

The car is lowered one level.

Driving and Driving Safety

191

Porsche Active Suspension

Indication of the selected running-gear

setup

Management (PASM)

The light-emitting diode in the button of the selec-

Various messages are shown on the multi-purpose

ted running-gear setup is lit.

display of the instrument panel.

In addition, the selected running-gear setup is indi-

f For further information on warning messages

cated on the multi-purpose display of the instru-

on the multi-purpose display:

ment panel for around 12 seconds.

Please see the chapter “OVERVIEW OF

WARNING MESSAGES” on Page 149.

Warning lights and warning

messages

Three different running-gear setups can be selec-

ted with the push of a button:

The warning light in the instrument panel comes

on if there is a system fault. A warning message is

- comfort

shown on the multi-purpose display of the instru-

- normal

ment panel.

- sport

f Adapt your driving style to the changed condi-

tions.

If the running-gear setups “comfort” or “normal”

have been selected, the system automatically

f To remedy the fault, consult an authorized

Selecting the running-gear setup

changes the setup to “sport” when the car is dri-

Porsche dealer.

1. Switch ignition on.

ven in a sporty manner.

2. Press the appropriate button.

Note on operation

The running-gear setup selected last is stored in

memory after the ignition is switched off.

Driving and Driving Safety

193

Maintenance Note

f

Always drive with the engine running.

Off-Road Driving

Power steering assistance is provided only

Please bear in mind that off-road driving subjects

Please read this chapter carefully before driving

with the engine running.

all vehicle components to considerably more wear

off road with your Porsche.

than normal use, making professional inspection

f

Drive slowly and uniformly.

The information provided will familiarise you with

and maintenance after each use a vital precondi-

f

Always make sure that the wheels touch the

the special advantages of your vehicle, allowing

tion for functioning and safety.

ground.

you to arrive at your destination safely every time.

Grains of sand, dirt particles and other abrasive

f

Before driving through water, check the water

We recommend practicing on less rugged terrain.

materials entering the brakes can cause exces-

depth, the condition of the surface beneath it

sive wear or unpredictable braking action.

and the speed of the water.

Vehicles with SportDesign package

Rules for off-road driving

f

Look out for obstacles such as boulders,

holes, tree stumps or ruts.

Caution!

f

Ensure vehicle is equipped with approved all-

f

Always keep the sliding/lifting roof or

Risk of damage. On vehicles with Sport-

terrain tires.

Panorama roof system and the side windows

Design package, front, rear, and side

f

Pay attention to the ground clearance of the

closed while driving.

member trim are painted. Off-road driving

can seriously damage these trim parts.

vehicle.

f

Do not depart from marked routes or paths.

Please see the chapter “GROUND

f When driving off-road, make sure these parts

CLEARANCE” on Page 357.

f

Respect Nature.

are not damaged.

Always obey off-limits signs.

f

Activate Low Range.

f Make sure there is sufficient clearance

Please see the chapter “SELECTING OFF-

between obstacles and the underside of the

ROAD DRIVING PROGRAM” on Page 178.

vehicle.

f

Stow or fasten luggage and loads securely.

f Avoid driving through water.

Please see the chapter “LOADING

f Do not use side member trims or rear wheel

INFORMATION” on Page 231.

spoilers as a running board.

f

If unknown terrain is obscured from view,

examine it on foot first and traverse it with

extreme caution.

This way, obstacles are easier to recognize

and damage to the vehicle is avoided.

Driving and Driving Safety

195

Driving systems for off-road driving

Vehicles with SportDesign package

After driving off road

Specially adapted driving programs or power-

Caution!

Off-road driving places a greater burden on the

transmission and running-gear control systems

vehicle than does normal driving on roads.

Risk of damage. On vehicles with Sport-

are available for off-road driving:

Design package, front, rear, and side

We recommend inspecting the vehicle after off-

- Off-road program Low Range

member trim are painted. Off-road driving

road driving. Potential damage poses an accident

can seriously damage these trim parts.

risk and impairs driving comfort. Damage on the

- Off-road PSM

car is recognized in good time if the car is

f

When driving off-road, make sure these parts

- Off-road ABS

checked.

are not damaged.

- Center differential lock

f

Make sure there is sufficient clearance

Caution!

– Rear differential lock

between obstacles and the underside of the

Car damage poses an accident risk for the

vehicle.

f Please see the chapter “POWER-TRANSMISSI-

vehicle occupants and other road users.

ON AND RUNNING-GEAR CONTROL SYSTEMS”

f

Avoid driving through water.

f

In cases of doubt, have your vehicle checked

on Page 181.

f

Do not use side member trims or rear wheel

by your authorized Porsche dealer.

spoilers as a running board.

Before driving off

f

Examine tires for signs of damage such as

cuts, tears, bulges or foreign objects stuck in

Tires

the tread.

Replace a damaged tire if necessary.

f Check tread depth and tire pressure.

f

Have any damage to your vehicle repaired by

f Check for damage and remove any foreign

an authorized Porsche dealer without delay.

objects (e.g. stones) from the tread.

f Replace missing valve caps.

Rims

f Replace dented or damaged rims before

driving off road.

196 Driving and Driving Safety

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