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Driving and Driving Safety
– 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.
Combined operation of PSM and PTM
In order to ensure optimum stabilisation of the
vehicle, torque distribution between the front and
rear wheels is adapted and the rear differential
lock is controlled on vehicles with PDCC.
In the event of a PTM fault, PSM cannot be
switched off.
If PSM is switched off, it is switched on again
automatically.
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.
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.
