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Driving stability control systems, Technology for comfort, convenience and safety, Driving stability control systems – BMW X3 3.0i SAV 2004 User Manual

Page 52

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Technology for comfort, convenience and safety

50

Limits of the system

Even with PDC, final responsibility for
estimating the distance between the

vehicle and any obstructions always
remains with the driver. Even when sensors
are involved, there is a blind spot in which
objects cannot be detected. The system is
also subject to the physical limits that apply
to all forms of ultrasonic measurement,
such as those encountered with tow bars
and trailer couplings, or thin and wedge-
shaped objects etc. Low objects already
displayed, e.g. a curb, can also disappear
from the detection area of the sensors
again before a continuous tone sounds.
Loud sources of sound, inside and outside
the vehicle, could drown out the PDC sig-
nal tone.

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Keep the sensors clean and free of ice
or snow in order to ensure that they

will continue to operate effectively.
Do not apply high pressure spray to the
sensors for a prolonged period of time.
Keep the spray at least 4 in/10 cm away
from the sensors.

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Driving stability control
systems

Your BMW is equipped with an extended
array of systems designed to enhance and
maintain vehicle stability under extreme
conditions. The following section describes
these functions based on ABS, DSC, HDC
and xDrive.

Antilock Brake System ABS

ABS enhances active safety by preventing
the wheels from locking under braking. The
vehicle continues to be steerable during
hard braking.
ABS also includes Electronic brake-force
distribution EBV.
Safe braking, refer to page

77

.

Electronic brake-force distribution
EBV

EBV controls the brake system's applica-
tion pressure at the rear wheels to ensure
stable deceleration.

Dynamic Brake Control DBC

The Dynamic Brake Control actively sup-
ports the driver in dangerous braking situa-
tions. Quickly pumping the brake pedal
increases the braking effect with low pedal
pressure so that the shortest possible
braking distance is achieved. This system
exploits all of the benefits provided by ABS.

Do not reduce the pressure on the brake
pedal for the duration of the brake applica-
tion. DBC is deactivated when you release
the brake pedal.

Dynamic Stability Control DSC

The concept

DSC maintains vehicle stability, even in
critical driving situations.

The DSC is operational every time you start
the engine.

The system optimizes the driving stability
during acceleration and when starting from
a standstill. The system recognizes any
tendency for the vehicle to assume an
unstable attitude such as oversteer or
understeer; it then counteracts this ten-
dency with a combination of graduated
reductions in engine torque and selective
braking intervention at individual wheels.
DSC provides optimal stability within the
limits defined by the laws of physics.

The laws of physics cannot be
repealed, even with DSC. An appro-

priate driving style always remains the
responsibility of the driver. Avoid using the
additional safety margin provided by the
system as an excuse for taking unneces-
sary risks.

Do not make any modifications to the DSC
system. Never allow anyone other than
authorized professional technicians to
carry out service or repairs on the system.

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Online Edition for Part No. 01 41 0 157 631 - © 07/03 BMW AG

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