2001 BMW M3 CONVERTIBLE Owner's Manual

169n
IndexDataTechnologyRepairsCar careControlsOverview
The AM frequency bands (medium-
wave, long-wave and short-wave) allow
the reception of stations from great
distances because the broadcast
signals – propagated at ground level in
the form of surface waves – are also
reflected from the ionosphere as atmo-
spheric waves.
Frequency-modulation (FM) provides
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.
The limitations inherent to radio recep-
tion in a moving vehicle have been
minimized by a number of innovative
systems:
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 Diversity Antenna integrates
several FM antennas within the
convertible top compartment lid to
provide three separate sources for
receiving broadcast waves. An integral
processor automatically selects the
antenna with the best FM reception
quality at any given time. The selection
of the antenna takes place within milli-
seconds, and is therefore not noticed
by the radio listener.
Radio reception

170n
Dynamic Stability Control (DSC) Safety belt tensioner

Highly sensitive sensors monitor the
number of revolutions of the wheels,
steering angle, lateral acceleration,
brake pressure and the movement of
the vehicle around its vertical axis.
If differences in wheel speed should
occur, the system will recognize the
potential dangers associated with
wheel spin and will reduce the drive
torque; if necessary, it will do so using
brake intervention at the rear wheels as
well.
When instable vehicle operating condi-
tions are detected, the application of
the brakes with DSC can also act on the
front wheels to stabilize the vehicle.
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 a certain degree of
noise.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 tends to reduce the
tendency to slide under the lap belt
even more.

171n
IndexDataTechnologyRepairsCar careControlsOverview
M3 Engine conceptBMW M will continue to develop BMW
engines for the performance-oriented,
yet responsible driver. That is why value
is placed on an engine design that
guarantees maximum thrust over a
wide range of engine speeds.
This is done by using high-grade mate-
rials and optimum components. The
engine thereby produces higher engine
speeds than can be achieved with
conventional engines.
Combined with appropriate transmis-
sion ratios and a performance-oriented
engine electronics system, the torque
from this so-called "high-speed aspi-
rated engine" is abundant throughout
the entire engine speed range – from
1,000 to a max. 8,000 per minute.
In practice, this means improved accel-
eration and more spontaneous
response throughout the engine speed
range, thus providing even more driving
pleasure.

172n
Rain sensor
*
Depending on the amount of moisture
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 amount of moisture on the
windshield.
When the system is set to the "intermit-
tent" wiper speed, the wipers react
immediately – if water is splashed onto
the windshield by vehicles traveling
ahead of you, for example. As a result,
the rain sensor makes a contribution to
driving safety and comfort.

173n
IndexDataTechnologyRepairsCar careControlsOverview
Interior rearview mirror with automatic dimming feature The interior rearview mirror with auto-
matic dimming feature reduces glare
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.
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.

174n
Xenon lamps
*
The xenon lamps provide forward illu-
mination with significantly more bright-
ness and uniformity than the traditional
halogen lamps.
In a xenon lamp, an electric arc
replaces the filament in order to
generate intense illumination. A gas
mixture in a quartz glass tube with
metal vapor is ignited by a high electric
voltage. The arc that is generated is
then sustained by a lower voltage.
When the lamp is turned on there is a
brief period of high intensity. Maximum
brightness is attained in approx.
15 seconds.
Xenon lamps provide significantly
improved visibility, especially during
adverse weather conditions and difficult
driving situations (e. g. driving at night in
heavy rain or through road repair areas
where there are no lane markers).
Xenon lamps make a significant contri-
bution to highway safety since other
highway users, bicyclists and motorcy-
clists in the right lane, and pedestrians
are more easily detected.

175n
IndexDataTechnologyRepairsCar careControlsOverview
Rollover protection systemThe rollover protection system offers
protection in addition to the airbags and
the safety belts. It uses highly sensitive
sensors that respond immediately to
any unstable vehicle condition encoun-
tered while driving, e. g. a steep angle
or loss of wheel contact with the
ground. The protective bar in each rear
head restraint is triggered in this type of
situation.

176n