Porsche 911 Turbo Owner's Manual page 70

Examples of PSM control operations
– If the front wheels of the vehicle drift on a
bend, the rear wheel on the inside of the bend
is braked and the engine power is reduced if
necessary.
– If the rear of the vehicle swings out on a bend,
the front wheel on the outside of the bend is
braked.
Additional braking functions
– Pre-filling the brake system:
The brake system is prepared for possible
subsequent emergency braking if the acceler-
ator pedal is released suddenly and quickly.
The brake system is prefilled and the brake
pads are already applied gently to the brake
discs.
– Brake booster:
In the event of an emergency braking operation
where the pedal force is insufficient, a brake
booster provides the braking pressure neces-
sary for maximum deceleration at all 4 wheels.
Advantages of PSM
– Best possible traction and lane-holding ability
in all driving situations – even on road surfaces
with varying friction.
68
Operation, Safety
– The system compensates for undesired lateral
vehicle reactions when the driver releases the
accelerator pedal or brakes when cornering.
This compensation functions up to the
maximum lateral acceleration.
– PSM actively stabilizes the vehicle as required
during dynamic driving maneuvers (e.g. rapid
steering movements, during lane changes or
on alternating bends).
– Improved braking stability on bends and on
different or varying road surfaces.
– It improves braking function and shortens
stopping distance in the event of emergency
braking.
Readiness for operation
PSM is switched on automatically every time you
start the engine.
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
f Press PSM OFF button.
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 PSM multi-
functional light on the instrument panel is lit
and a message is shown on the on-board
computer.
An acoustic signal also sounds.
Note
When PSM is switched off, the additional braking
functions are deactivated. Automatic reactivation
in emergency situations is linked to the PSM
control.