2001 BMW 325Ci CONVERTIBLE acceleration

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IndexDataTechnologyRepairsCar careControlsOverview
ASC+T DSC*Reactivating ASC+TPress the button again; the indicator
lamp goes out.
The laws of physics cannot be
repealed, even with ASC+T. It will
always be the driver's responsibility to
drive in a manner that matches road
conditions. This is why you should not
use the additional safety margin the
system provides as an excuse to take
risks.<
For additional details concerning
ASC+T, please refer to the chapter
"Advanced Technology" on page 189.
The conceptDSC maintains vehicle stability, even in
critical driving situations.
The system optimizes vehicle stability
during acceleration and when starting
from a full stop, as well as optimizing
traction. In addition, it recognizes
unstable vehicle conditions, such as
understeering or oversteering, and, as
far as is possible within the laws of
physics, helps keeping the car on a
steady course by reducing the RPMs
and brake applications to the individual
wheels.
The DSC is operational every time you
start the engine. DSC includes the
functions of ADB and CBC, refer to
page 123.
The ADB (Automatic Differential
Braking) copies the function of conven-
tional differential and transverse lock
through brake intervention, and
increases traction whenever conditions
merit, e. g. when driving on snow-
covered roads.
If the DSC is switched off the ADB will
still be in ready mode.
Indicator lamp
The indicator lamp in the instru-
ment cluster goes out shortly
after you switch on the ignition.
Refer to page 21, 22.
Indicator lamp flashes:
DSC controls the drive and braking
forces.
The indicator lamp stays lit:
DSC has been switched off via the
button; ADB is operational.
ADB control intervention is not indi-
cated.
The indicator and the brake
warning lamps will remain on
the continuously:
The DSC, ADB and DBC have
been switched off via the button
or are defective.
The vehicle will remain completely
operational, however, without DSC. In
the event of a fault, please see your
BMW center. Refer to page 21, 22.
Indicator and warning lamps for
Canadian models.

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Roof-mounted luggage rack for the hardtop
*
AnchorsAccess to the anchors:
To open the cover (arrow), please use
the tool included with the roof-rack
system.
A special roof-rack system is available
for your BMW as an optional extra.
Please comply with the precautions
included with the installation instruc-
tions.
Because roof racks raise the center of
gravity of the vehicle when loaded, they
exercise a major effect on its handling
and steering response. You should
therefore always remember not to
exceed the approved roof weight, the
approved gross vehicle weight or the 46cde097
axle loads when loading the rack. Perti-
nent specifications are listed under
"Technical Data," page 198.
Make sure that the load is not too
heavy, and distribute it evenly.
Always load the heaviest pieces first (on
the bottom). Be sure that objects do not
project into the opening path of the
luggage compartment lid.
Secure the roof luggage correctly and
securely to prevent it from shifting or
being lost during driving (danger to
following traffic).
Drive smoothly and avoid sudden
acceleration or braking. Do not corner
at high speeds.
The roof load increases aerodynamic
resistance, which in turn increases fuel
consumption and places additional
stress on the vehicle itself.

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IndexDataTechnologyRepairsCar careControlsOverview
Antilock Brake System (ABS)Antilock Brake System (ABS)/
Cornering Brake Control (CBC) CBC is an advanced engineering
design of the ABS. When braking while
cornering at high speed or braking
during high lateral acceleration, or
when braking during a lane change,
vehicle stability is improved and
steering response is enhanced.
In the event of a malfunction
The ABS warning lamp in the
instrument cluster lights up,
refer to page 22. The brake
system then reverts to conventional
operation as on vehicles without ABS.
However, have the brake system
chekked by your BMW center as soon
as possible. To prevent undetected
defects and cumulative faults from
adversely affecting the brake system,
refer any problems to your BMW center
at the earliest opportunity.
ABS warning lamp for Canadian
models.
The brake-warning lamp comes
on along with the indicator
lamps for ABS and ASC+T/DSC,
refer to page 21, then the entire
control system for ABS, CBC
and ASC+T/DSC and ADB/DBC
has failed. Continue driving
cautiously and defensively.
Avoid full brake applications. This could
cause the vehicle to lose stability and
you might no longer be able to control
it.
Have the system checked by your BMW
center as soon as possible.
CBC, ABS and ASC+T/DSC and
ADB/DBC indicator and warning
lamps for Canadian models.

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IndexDataTechnologyRepairsCar careControlsOverview
To maintain good handling and vehicle
response, use only tires of a single
tread configuration from a single manu-
facturer. BMW tests and approves
wheel/tire combinations, beginning on
page 137.DOT Quality Grades Treadwear
Traction AA A B C
Temperature A B C
All passenger vehicle tires must
conform to Federal Safety
Requirements in addition to these
grades.< Tread wearThe tread wear grade is a comparative
rating based on the wear rate of the tire
when tested under controlled condi-
tions on a specified government test
course.
For example, a tire graded 150 would
wear one and one-half (1g) times as
well on the government course as a tire
graded 100. The relative performance
of tires depends upon the actual condi-
tions of their use, however, and may
depart significantly from the norm due
to variations in driving habits, service
practices and differences in road char-
acteristics and climate.
TractionThe traction grades, from highest to
lowest, are AA, A, B, and C.
Those grades represent the tire's ability
to stop on wet pavement as measured
under controlled conditions on speci-
fied government test surfaces of
asphalt and concrete. A tire marked C
may have poor traction performance.
The traction grade assigned to
this tire is based on straight-
ahead braking traction tests, and does
not include acceleration, cornering,
hydroplaning, or peak traction
characteristics.< TemperatureThe temperature grades are A (the
highest), B, and C, representing the
tire's resistance to the generation of
heat and its ability to dissipate heat
when tested under controlled condi-
tions on a specified indoor laboratory
test wheel.
Sustained high temperature can cause
the material of the tire to degenerate
and reduce tire life, and excessive
temperature can lead to sudden tire
failure. The grade C corresponds to a
level of performance which all
passenger vehicle tires must meet
under the Federal Motor Vehicle Safety
Standard No. 109. Grades B and A
represent higher levels of performance
on the laboratory test wheel than the
minimum required by law.
The temperature grade for this tire
is established for a tire that is
properly inflated and not overloaded.
Excessive speed, underinflation, or
excessive loading, either separately or
in combination, can cause heat buildup
and possible tire failure.< Uniform Tire Quality Grading Quality grades can be found where
applicable on the tire sidewall between
tread shoulder and maximum section
width. For example:
Tread wear 200 Traction AA
Temperature A
Do not use retreaded tires. Driving
safety may be impaired by their
use. This is due to the possible varia-
tions in casing structures and, in some
cases, to their extreme age, factors that
can lead to a decrease in their
durability.<
Tire replacement

188n
On vehicles with automatic transmis-
sion, the Adaptive Transmission Control
(ATC) uses a number of factors to
calculate the most efficient gear. In this
process, it considers your individual
driving style as well as current driving
conditions.
ATC recognizes your personal driving
style from the positions and movements
of the accelerator pedal, deceleration
when braking, and lateral acceleration
through curves. Based on different shift
characteristics Ð from comfort-oriented
to performance-oriented Ð ATC will
select the appropriate gear.
46cus020
In order to include driving conditions in
its calculations, ATC registers curves
and both uphill and downhill grades.
For example, if you maintain speed
through a curve, the transmission does
not shift up. On uphill grades, it shifts
up only when the engine speed
increases in order to make more effi-
cient use of power reserves. On down-
hill grades, ATC shifts down when the
speed of the vehicle increases and the
driver must apply the brakes.
ATC
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189n
IndexDataTechnologyRepairsCar careControlsOverview
Deceleration sensors continuously
monitor the acceleration forces acting
upon the vehicle. If, as the result of a
frontal collision, a deceleration is
reached at which the protection of the
safety belts alone is no longer
adequate, the gas generators of the
driver and passenger-front airbags are
ignited. However, the passenger-side
airbag is only triggered if an additional
sensor has recognized that the
passenger seat is occupied.
In the event of a side collision, the side
airbags in the front and/or rear
* are
triggered if necessary.
390de012
The airbags located under the marked
covers inflate and unfold in a matter of
a few milliseconds. In this process, they
tear through the designed separation
points of the upholstered covers or
press them out.
Because the inflation process must be
virtually instantaneous, it is accompa-
nied by a certain amount of ignition and
inflation noise, which will be drowned
out by the noise from the accident
itself. The gas required to inflate the
airbags is not dangerous, and the
associated smoke then dissipates.
The entire process is completed within
fractions of a second.Highly sensitive sensors monitor the
number of revolutions of the wheels.
When equipped with DSC, they also
monitor steering angle, lateral accelera-
tion, brake pressure and the movement
of the vehicle around its vertical axis.
If differences in the wheel speeds
occur, ASC+T counteracts the danger
of wheelspin by reducing engine
torque; if necessary, ASC+T will also
respond by applying the brakes to the
rear wheels.
In addition, DSC permanently monitors
the vehicle's current operating condi-
tion and compares it with an ideal
condition that is calculated from the
sensor's signals. If deviations from this
occur (understeering or oversteering,
for instance), DSC can stabilize the
vehicle in fractions of a second by
reducing engine output and with the
assistance of braking intervention at
individual wheels. Dangerous skids are
thus prevented before they can even
start, and all of this is possible, of
course, only within physically possible
limits. You may need some time to
become accustomed to the system's
intervention. However, it provides
optimum drive force and vehicle
stability. The braking intervention may
be accompanied by sounds specific to
the system.
Airbags ASC+T/DSC
*