ESP BMW 323Ci CONVERTIBLE 2000 E46 Service Manual

174n
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 atmospheric waves that are re-
flected from the ionosphere.
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. 360de084
The limitations inherent to radio recep-
tion in a moving vehicle have been min-
imized by a number of innovative sys-
tem designs:
The "Radio Data System" (RDS) makes
sure that, for stations broadcasting on
several frequencies, the radio automati-
cally tunes to the frequency with the
best reception quality.
With the Diversity Antenna system, sev-
eral FM antennas are integrated within
the convertible top compartment lid to
provide three separate sources for re-
ceiving broadcast waves. An integral
processor automatically selects the an-
tenna with the best FM reception qual-
ity at any given time. The selection of
the antenna takes place within millisec-
onds, and is therefore not noticed by
the radio listener.The safety belt tensioners respond to
severe head-on collisions by tightening
the belts to ensure that occupants
remain firmly positioned in their seats.
A gas-pressure system retracts the
buckle assembly to tension the shoul-
der and lap belts within fractions of a
second. This reduces the tendency to
slide under the lap belt.
390de330

175n
IndexDataTechnologyRepairsCar careControlsOverview
Interior rearview mirror with automatic dimmer
*
The interior rearview mirror with auto-
matic dimming feature reduces glare 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 light sensor is mounted on the front
of the mirror housing. This sensor, the
one that is directed forward, measures
light intensity in the area ahead of the
vehicle. The second sensor is inte-
grated within the mirror's glass. The
electronic control system compares the
light intensity from front and rear. The
difference provides the basic parameter
used to modulate an electrical current
and induce chemical changes in a semi-
solid layer incorporated in the lens.46cus036
The semisolid reacts chemically to this
electrical current, dimming the mirror
through an infinitely-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.

179n
IndexDataTechnologyRepairsCar careControlsOverview
Rollover protection syste
m
Xenon lamps
*
The rollover protection system offers
additional protection apart from the air-
bags and safety belts. The system has
highly sensitive sensors that react im-
mediately upon detecting an unstable
vehicle condition, i.e. when the vehicle
is tilted to a critical degree, or if the
wheels are not making proper ground
contact. In this kind of situation, the
protective bar in each rear head
restraint is triggered.
Xenon lamps illuminate the side and
front areas of the vehicle with signifi-
cantly more brightness and uniformity
than the traditional halogen lamp.
In a xenon lamp, an electric arc re-
places 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 warm-up
period. Maximum brightness is attained
in approx. 15 seconds.
390de134
Xenon lamps provide significantly im-
proved visibility, especially during ad-
verse weather and poor driving condi-
tions e.g. driving at night in heavy rain
or through road repair areas where
there are no lane markers.
Vehicles with xenon lamps are equipped
with automatic headlamp range control.
As a result, the highway is always opti-
mally lighted, regardless of road condi-
tions, and drivers in oncoming traffic are
not blinded.
Xenon lamps make a significant contri-
bution to highway safety since pedestri-
ans and other highway users, bicyclists
and motorcyclists in the right lane, are
more easily detected.

So that you will have important
specifications available when you
stop to refuel, we recommend that
you supplement this table with data
which apply to your vehicle.
Fuel
Engine oil The space between the two marks on
the dipstick corresponds to approx.
1.1 US quarts (1 liter). Designation
AKI: minimum
AKI: for rated performance
AKI: for enhanced
performance
QualityTire inflation pressure
Summer Winter
Front Rear Front Rear
2 persons
4 persons plus luggage
Refueling