Shifting Gear, Traction Systems
199
Selector lever positionIndicator for selector lever position and
engaged gearWhen the engine is running, the selector lever po-
sition and engaged gear are indicated.If there is a fault in the transmission:
– All gear indicators light up
– The transmission no longer shifts.
fHave the fault rectified immediately at your au-
thorized Porsche dealer.
Selector Lever PositionsP – Parking lockIn selector lever position P, the driven wheels are
mechanically locked.
fEngage parking lock only when vehicle is
stationary.
fEngage parking lock after applying the park-
ing brake and release it before releasing the
parking brake.
fAlways apply the parking brake before leaving
the vehicle.
The ignition key can be withdrawn only in selector
lever position P.R – ReversefSelect reverse only if car is stationary and the
brake is applied.N – NeutralSelector lever position N must be selected for
towing or in car washes, for example.
fSelect the desired position for moving off
(D, M or R) only when the engine is idling and
when depressing the brake pedal.
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Shifting Gear, Traction Systems
D - Automatic selection mode (in the road
driving program)The functions of selector lever positions Dand M
differ in the on-road program, High Range, and in
the off-road program, Low Range.
fUse selector lever position D for “normal” driv-
ing.
The gears are shifted automatically according
to the accelerator position and speed.
Depending on the way the vehicle is driven and on
the resistance (e.g. uphill), the gear-changing
points are shifted towards higher or lower engine-
speed ranges. Movement of the accelerator,
driving speed, longitudinal and lateral acceleration
and the road profile all have an influence on the
gear-changing characteristic.
When PSM is switched off, transmission gear
changes are done at higher engine speeds.
Unwanted upward shifts, e.g. before bends, are
prevented by swiftly releasing the accelerator ped-
al.
Depending on lateral acceleration, upward chang-
es on bends are not made until the engine-speed
limit is reached.
During braking, and depending on the amount of
deceleration, the Tiptronic changes down earlier.
For subsequent cornering, the right gear is en-
gaged when pressure is applied to the brakes be-
fore the bend.The bend is taken in the right gear, and when you
accelerate out of the bend you do not have to
change down.
Moving off
In 2nd gear, the vehicle moves off with the throttle
only slightly open. Move off in 1st gear with the
throttle open wider or when the engine is cold.
When PSM is switched off, the car generally
moves off in 1st gear.
Shifting gear on the steering wheel
By shifting gear with the rocker switches on the
steering wheel, you can temporarily change from
automatic selection mode D to manual selection
mode M.
Advantages
– Shifting down before bends and on entering
built-up areas.
– Shifting down on downward slopes (engine
braking).
– Shifting down for brief spurts of acceleration.
– Selecting 1st or 2nd gear for moving off.
The manual selection mode remains engaged:
– For cornering (depending on the lateral accel-
eration) and overrunning,
– When the vehicle is stationary (e.g. at a junc-
tion).The system leaves manual selection mode:
– automatically after around 8 seconds
(unless car is cornering, overrunning or
stationary),
– if you depress the accelerator to kickdown.
Temporary change-down
Precondition
– Speed is higher than approx. 33 mph
(54 km/h).
fDepress accelerator quickly.
The Tiptronic changes temporarily to the sport-
iest gear-changing map, i.e. to the highest pos-
sible gear-changing points. Correspondingly,
the transmission shifts down immediately by
one, two or three gears.
Ending the function
fRelease the accelerator markedly (by approx.
25%).
Shifting Gear, Traction Systems
201
Kickdown
The kickdown function is active in selector lever
position D.
fFor optimum acceleration, e.g. when overtak-
ing, depress the accelerator pedal beyond the
full-throttle point (kickdown).
The transmission shifts down depending on the
speed of travel and engine speed.
Upward shifts occur at the highest possible engine
speeds.
These gear-changing speeds remain active until
the accelerator is released to approx. 80% of the
full-throttle position.D - Automatic selection mode (in the off-
road driving program)The functions of selector lever positions Dand M
differ in the on-road program, High Range, and in
the off-road program, Low Range.
fUse selector lever position D for “normal” driv-
ing.
The gears are shifted automatically according
to the accelerator position and speed.
The gears are shifted automatically according to
the accelerator position and speed. The gear-
changing points have been adjusted to achieve the
best possible vehicle control on difficult terrain.Depending on the route profile, the gear-changing
points are shifted towards higher or lower engine-
speed ranges. On steep downhill stretches, up-
ward shifts are prevented until medium engine
speeds are reached (at least 2,500 rpm).
When the car is overrunning, an automatic upshift
does not occur when the engine speed limit is
reached.
Moving off
The car moves off in 1st gear.
Shifting gear on the steering wheel
By shifting gear with the rocker switches on the
steering wheel, you can temporarily change from
automatic selection mode D to manual selection
mode M.
Advantages
– Shifting down on downward slopes (engine
braking).
– Shifting down for brief spurts of acceleration.
– Selecting 1st/2nd or 3rd gear for moving off.
The manual selection mode remains engaged:
– For overrunning
– Depending on lateral acceleration
– When the vehicle is stationary (e.g. at a junc-
tion).The system leaves manual selection mode:
– Automatically after around 8 seconds
(unless car is subject to high lateral accelera-
tion, is overrunning or stationary),
– if you depress the accelerator to kickdown.
Kickdown
The kickdown function is active in selector lever
position D.
fFor optimum acceleration, e.g. when overtak-
ing, depress the accelerator pedal beyond the
full-throttle point (kickdown).
The transmission shifts down depending on the
speed of travel and engine speed.
Upward shifts occur at the highest possible engine
speeds.
These gear-changing speeds remain active until
the accelerator is released to approx. 80% of the
full-throttle position.
Tip on driving
Unlike in the on-road driving program, an auto-
matic upshift is not performed in manual selection
modeM when the engine-speed limit is reached.
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Shifting Gear, Traction Systems
M - Manual selection mode (in the road
driving program)The functions of selector lever positions Dand M
differ in the on-road program, High Range, and in
the off-road program, Low Range.
The currently selected gear is retained if you
change from D to M.
If you change from M to D, the gear-changing map
suitable for your current driving style is selected
and the appropriate gear is selected.
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 accelerat-ing (e.g. to overtake).
Shifting up
fPress upper part (+) of a rocker switch Aor
fPush selector lever B forward in the M gate.
Shifting down
fPress lower part (–) of a rocker switch Aor
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 chang-
es 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 press-
ing rocker switches A or selector lever B twice.
If PSM is active and the engine-speed limit is
reached, an automatic upward shift is performed
or, just before idling speed is reached, a down-
ward shift is performed.
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 instrument panel will display se-
lector lever position D.
fTo remedy the fault, please consult an autho-
rized Porsche dealer.
Shifting Gear, Traction Systems
203
M - Manual selection mode (in the off-
road driving program)The functions of selector lever positions Dand M
differ in the on-road program, High Range, and in
the off-road program, Low Range.
The currently selected gear is retained if you
change from D to M.
If you change from M to D, the gear-changing map
suitable for your current driving style is selected
and the appropriate gear is selected.
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 accelerat-ing (e.g. to overtake).
Tip on driving
The kickdown function is not active in selector le-
ver 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 Aor
fPush selector lever B forward in the M gate.Shifting down
fPress lower part (–) of a rocker switch Aor
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 chang-
es 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 press-
ing rocker switches A or selector lever B twice.
The gear is changed down automatically just be-
fore 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.
fHave the fault eliminated at your authorized
Porsche dealer.
StoppingfFor a brief stop (e.g. at a traffic light), leave the
selector lever in drive position and hold the ve-
hicle with the brake pedal.
fDo not hold the car on a slope using the accel-
erator. Use the brake pedal or the parking
brake instead.
fBefore leaving the vehicle, always apply the
handbrake and move the selector lever to
positionP.
Tip on driving
In selector lever positions D and M, the Hillholder
prevents the car from rolling backward when it has
been stopped on an upward slope with the engine
running.
fPlease observe the chapter “HILLHOLDER” on
Page 218.
Shifting Gear, Traction Systems
209
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
changed over to fully engaged state by the
automatic 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.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.
Shifting Gear, Traction Systems
211
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
Shifting Gear, Traction Systems
213
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.
Caution!
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.