Porsche Cayenne Owner's Manual page 182

Warning!
In spite of the advantages of PTM or four-wheel dri-
ve, it is still the driver's responsibility to adapt her/
his driving style and maneuvers in line with road
and weather conditions, as well as the traffic situ-
ation.
The increased safety that is provided should not
induce you to take greater risks with your safety.
The limits set by the physics of driving cannot be
overcome, even with PTM or four-wheel drive.
Risks of accident due to inappropriate speed
cannot be reduced by PTM.
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
axles. The system realizes this optimal traction by
intervening 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.
182
Driving and Driving Safety
Advantages of PTM
– Obvious improvement in traction, driving
stability 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
sportier setup of the running gear.
– The TCS and ABD provide even better traction
for all wheels.
Full-time all-wheel drive
With the four-wheel drive, the drive power is
variably distributed to the front and rear wheels.
Power distribution and wheel speed compensation
between the front and rear axles is realized 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 achie-
ved, even on an unfavorable road surface.
Full-time four-wheel drive ensures optimal handling
and greater stability.
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 recognizes 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
becomes 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.