Driving and Driving Safety
165
foot pressure must be increased after the
brake pedal has begun vibrating.
Examples of PSM control operations
– If the “front wheels of the vehicle drift” on a
bend, the engine power is reduced and the
rear wheel on the inside of the bend is braked
if necessary.
– If the rear of the vehicle swings out on a bend,
the front wheel on the outside of the bend is
braked.
– Brake system prefilling:
The brake system is prepared for possible
subsequent emergency braking if the
accelerator 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 (Hydraulic Brake Assist):
In the event of an emergency braking operation
where the pedal force is insufficient, a brake
booster provides the braking pressure
necessary for maximum deceleration at all
4 wheels.
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.
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 vehicle moves off on
a level gravel surface, traction control already
becomes active at low engine speeds. If a large
amount of propulsive power is required, e.g. when
driving off on an uphill slope or for rapid
acceleration, the ABD system is adapted
accordingly.
Anti-slip control (ASR)
The anti-slip control system prevents the wheels
from spinning by adjusting the engine power,
thereby ensuring good lane-holding ability and
stable handling.
Engine drag torque control (MSR)
In conditions of excessive slip, the engine drag
torque 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
during countersteering.
Switching off PSM
f
Press button
for at least 1 second.
PSM is switched off after a short delay.
The indicator light on the button and the
PSM OFF warning light on the instrument
panel light up.
The warning “
PSM off
” appears on the
multi-function display in the instrument panel.
When braking in the ABS control range
,
the vehicle is stabilised even when PSM is
switched off.
One-sided spinning
of the wheels is prevented,
even with PSM switched off.
14_C7NF_21.book Seite 165 Mittwoch, 26. März 2014 12:15 12
