BMW 330Ci COUPE 2001 E46 Owner's Manual

171n
IndexDataTechnologyRepairsCar careControlsOverview

172n

Overview
Controls and features
Operation, care
and maintenance
Owner service procedures
Technical data
Index Advanced technology
173n
IndexDataTechnologyRepairsCar careControlsOverview
Adaptive Transmission Control
(ATC)174
Airbags175
Automatic Stability Control plus
Traction (ASC+T)/Dynamic
Stability Control (DSC)175
Radio reception176
Safety belt tensioner176
Interior rearview mirror
with automatic dimming
feature177
Rain sensor178
Tire Pressure Control (RDC)179
Self-diagnostics180
Xenon lamps181
Technol-

174n
On vehicles with automatic transmis-
sion, the ATC (Adaptive Transmission
Control) uses a number of factors to
calculate the maximally efficient gear.
In this process, it considers your indi-
vidual 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.
462us011
In order to include driving conditions in
its calculations, ATC registers curves
and both uphill and downhill gradients.
For example, if you maintain speed
through a curve, the transmission does
not shift up. On uphill gradients, it shifts
up only when the engine speed
increases in order to make more effi-
cient use of power reserves. On down-
hill gradients, ATC shifts down when
the speed of the vehicle increases and
the driver must apply the brakes.
ATC
*

175n
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 head
and side airbags in the front or rear
* are
triggered if necessary.
390de319
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. As a result,
dangerous skids can be prevented even
as they are just beginning. But this is
only possible within the laws of physics.
You may need some time to become
accustomed to this system's interven-
tion. 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
*

176n
Radio reception Safety belt tensionerThe AM frequency bands (medium-
wave, long-wave and short-wave) make
it possible to receive stations from a
great distance, because the broadcast
signals travel not only along the ground
as surface waves, but also as atmo-
spheric waves that are reflected from
the ionosphere.
Frequency modulation (FM) offers
substantially better sound quality than
the other frequencies. However,
because FM transmissions rely on line-
of-sight broadcast waves, their effec-
tive reception range is limited. 360de084
The limitations inherent to radio recep-
tion in a moving vehicle have been
minimized by a number of innovative
system designs:
The Radio Data System (RDS) makes
sure that, for broadcast stations
sending on several frequencies, the
radio automatically tunes to the
frequency with the best reception
quality.
The Antenna Diversity system employs
several FM antennas integrated within
the rear window to provide three sepa-
rate sources for receiving broadcast
waves. An integral processor automati-
cally selects the antenna with the best
FM reception quality at any given time.
The selection of the antenna takes
place within milliseconds, and is
therefore not noticed by the radio
listener.The safety belt tensioner makes sure
that the belt tightens during a head-on
collision to ensure that occupants
remain firmly positioned in their seats.
A gas-pressure system retracts the
buckle assembly to tension the
shoulder and lap belts within fractions
of a second. This reduces the tendency
to slide under the lap belt.
390de330

177n
IndexDataTechnologyRepairsCar careControlsOverview
Interior rearview mirror with automatic dimming feature
*
The interior rearview mirror with auto-
matic dimming feature reduces blinding
from following traffic by adapting the
intensity of the reflected images to
correspond to levels of light registered
by the unit's sensors. The mirror reverts
to its undimmed setting as soon as the
light source disappears. One lamp
sensor is mounted on the front of the
mirror housing. This sensor, which is
directed forward, measures light inten-
sity in the area ahead of the vehicle.
The second sensor is integrated within
the mirror's glass. The electronic
control system compares the light
intensity from front and rear. The differ-
ence provides the basic parameter
used to modulate an electrical current
and induce chemical changes in a
semisolid layer incorporated in the lens.463us013
The semisolid reacts chemically to this
electrical current, thus providing
dimming of the mirror through an infi-
nitely-variable range (electrochromic
technology).
As a result, it is no longer necessary to
dim the mirror manually, and the driver
can concentrate completely on traffic
conditions.

178n
Rain sensor
*
Depending on the degree of wetness
on the windshield, the rain sensor
controls the operation of the windshield
wipers.
Infrared light is carried along the
surface of the windshield in an optical
conductor in such a manner that it is
reflected completely when the wind-
shield is dry. The quantity of reflected
light is measured.
If there is moisture on the glass, the
amount of light reflected is reduced
since the infrared light at the surface of
the windshield can escape. The quan-
tity of reflected light is thus a means of
gauging the degree of wetness on the
windshield.390de133
When the system is set to the "Inter-
mittent" wiper speed, the wipers react
immediately Ð if water is splashed onto
the windshield by vehicles traveling
ahead of you, for example. As a result,
the rain sensor provides a contribution
to driving safety and comfort.

179n
IndexDataTechnologyRepairsCar careControlsOverview
Tire Pressure Control (RDC)*This system regularly checks tire pres-
sure and monitors all four tires even
while driving, so you do not have to.
Behind the valve stem in every wheel,
there is an extended-life electronic chip
that contains a pressure sensor, a
transmitter and a battery. The pressure
is measured in extremely short time
intervals and then transmitted by a
radio signal. If an irregularity is
detected, the transmission rate is
increased. 462de257
Located near each wheel and
embedded in the vehicle body is an
antenna that receives signals from the
wheel. A central electronics system
evaluates the quadruple signals and
forwards any changes.
The RDC provides an important contri-
bution to driving safety.

180n
Self-diagnostics All of the important electrical and elec-
tronic systems in the vehicle are tested
regularly and automatically Ð the driver
does not have to perform any extra
operations or adjustments.
The indicator lamps come on briefly
after the ignition has been turned on.
While you are driving, the functional
status of the actuator motors (for the
windshield wipers, power windows,
seats, sliding/tilt sunroof, etc.) is
constantly being analyzed by electrical
measurements in the relays.462us038
In the same manner, the electrical
resistance of the airbag ignition genera-
tors and all of the remaining airbag
components is measured at all times.
Any fault in this system would be
detected immediately by a current fluc-
tuation that would necessarily accom-
pany it. The fault would be indicated
immediately by the airbag warning
lamp.
Even after you shut off the engine, the
overall functional status of your vehicle
is monitored. For example, all of the
flaps of the heating and ventilation
system travel to the nearest limit posi-
tion. This way you can be assured that
the defrost function is always available,
even if, for example, a defect crops up
in the air conditioner/automatic climate
control during the night while the
engine has been turned off.
A calibration cycle runs every tenth time
the engine is shut off. During this cycle,
the actuator motors of all the heating
and ventilation flaps travel to their limit
stops in both directions. The limit
positions and the return travel paths are
checked in this manner in order to
ensure that appropriate adjustments for
the operating elements can be made at
any time.You will hear the sounds of the air flaps
as the air conditioner/automatic climate
control carries out its self-diagnostic
functions after the ignition has been
shut off. All of the other self-diagnostics
functions operate silently in the back-
ground.
Any possible faults detected during
these self-diagnostics can be read out
and corrected by your BMW center
during the next regularly scheduled
maintenance.