Porsche 911 Carrera - Manual (Page 82)

Additional functions for vehicles with
four-wheel drive
– Pre-filling the brake system: If you suddenly
and quickly take your foot off the accelerator
pedal, the brake system gets prepared for
possible emergency braking. The brake
system is pre-filled which lightly presses the
brake pads on the brake discs.
Brake boost: If emergency braking does not
have sufficient pedal pressure, the brake boost
produces the brake pressure necessary for
maximum deceleration on all 4 wheels.
The PSM should always be switched on
during “normal” driving.
However, it may be advantageous to switch off
PSM temporarily in exceptional situations, for
example:
–
On a loose surface or in deep snow,
– When “rocking the vehicle free” and
– When using snow chains.
Switching off PSM
Press PSM OFF button. PSM is switched off
after a short delay. The light-emitting diode
in the button is illuminated. When the PSM is
switched off, the multifunctional PSM light on
the instrument panel is lit and a message is
shown by the on-board computer. An acoustic
signal also sounds.
Vehicles with four-wheel drive
When PSM is switched off, the additional braking
functions are deactivated. The automatic reactiva-
tion in emergency situations is coupled to the PSM
control in emergency situations.
The following functions stabilize the vehicle in
emergency situations, even with PSM switched off:
–
When PSM is off, the vehicle is stabilized as
soon as one of the two front wheels enters the
ABS control range.
– When PSM is off and Sport mode is on, the
vehicle is stabilized as soon as both front
wheels enter the ABS control range.
One-sided spinning of the wheels is prevented,
even with PSM switched off.
Switching PSM back on
Press PSM OFF button. PSM is switched on
after a short delay. The light-emitting diode
in the button and the multifunctional PSM
light go out. The on-board computer shows a
message.
Sport mode
A sportier car set-up is obtained when Sport mode
is switched on. PSM interventions are later than in
Normal mode; the vehicle can be maneuvered with
greater agility at its performance limits, without
the need to dispense with the assistance of PSM
in emergency situations. This helps to achieve
optimal lap times, particularly on race circuits and
a dry road surface.
80
Controls, Instruments