Porsche Stability Management (Psm) - Porsche 911 Manual

Porsche Stability
Management (PSM)
Porsche Stability Management (PSM) is an active
control system for stabilising the vehicle in extreme
driving situations. It is automatically enabled when
the engine starts. PSM makes use of both the Auto-
matic Brake Differential (ABD) and Anti-slip Regula-
tion (ASR) systems, as well as the functions of the
Anti-lock Brake System (ABS) and engine drag tor-
que control system (MSR).
Loss of control over the
WARNING
vehicle
Risk of accidents due to inappropriate speed cannot
be reduced by PSM.
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 over-
come, even with PSM.
e Despite the advantages of PSM, the driver is re-
sponsible for adapting his or her driving style and
manoeuvres in line with road and weather con-
ditions, as well as the traffic situation.
The events below inform the driver of PSM control
operations:
– PSM warning light flashes on the instrument
cluster.
– Hydraulic noises can be heard.
– The vehicle decelerates and steering-wheel
forces are altered as PSM controls the brakes.
– Engine power is reduced.
– The brake pedal pulsates and its position is
changed during braking. To achieve full vehicle
deceleration, the foot pressure must be in-
creased after the brake pedal starts to pulsate.
Automatic Brake Differential (ABD)
If one wheel of a driven axle starts to spin, it is
braked so that the other wheel on the same axle can
be driven.
Anti-slip Regulation (ASR)
The Anti-slip Regulation system prevents the wheels
from spinning by adjusting the engine power, there-
by ensuring good lane-holding ability and stable
handling.
Engine drag torque control (MSR)
In conditions of excessive slip, the engine drag tor-
que control system prevents all driven wheels from
locking up when the vehicle is overrunning. This is
also the case for downshifts on a slippery road.
Steering torque pulse
The steering torque pulse provides the driver with
steering assistance when braking on road surfaces
with differing friction values.
Additional steering forces also assist the driver dur-
ing countersteering.
Activating PSM Sport
b b Vehicles with Sport Chrono package
During PSM Sport operation, the system switches to
a particular sporty mode.
Limited PSM support
WARNING
In PSM Sport mode, PSM support is limited in crit-
ical driving situations outside the ABS control range.
e PSM Sport should always be switched off during
"normal" driving.
e Press the
button briefly.

Porsche Stability Management (PSM)

The PSM OFF warning light on the instrument
cluster comes on. The button
A message stating that PSM Sport is activated
appears on the instrument cluster.
Switching PSM off
Fig. 154: PSM OFF button in the switch panel
No PSM support
WARNING
When PSM is switched off, PSM support is no longer
provided in critical driving situations outside the ABS
control range.
e PSM should always be switched on during "nor-
mal" driving.
e Briefly press the
button (vehicles with Sport
Chrono package: press the button for at least
2 seconds).
PSM is switched off after a short delay.
A
lights up red.
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