2001 BMW 325Ci COUPE Owner's Manual

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.

181n
IndexDataTechnologyRepairsCar careControlsOverview
Xenon lamps
*
The xenon lamp provides forward illu-
mination with significantly more bright-
ness and uniformity than the traditional
halogen lamp.
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 warm-up period.
Maximum brightness is attained in
approx. 15 seconds.390de134
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).
Vehicles with xenon lamps are equipped
with automatic headlamp range control.
As a result, the lane ahead of you is
always optimally lighted, even under
varying load conditions, and drivers in
oncoming traffic are not blinded.
Xenon lamps make a significant contri-
bution to highway safety since other
highway users, bicyclists and motor-
cyclists in the right lane, and pedes-
trians are more easily detected.

182n

Overview
Controls and features
Operation, care
and maintenance
Owner service procedures
Technical data
Index Advanced technology
183n
IndexDataTechnologyRepairsCar careControlsOverview
Engine data184
Dimensions185
Weights186
Capacities187
Electrical system188
V-belts188
Data

184n
BMW 325Ci BMW 330Ci
Displacement
Number of cylinderscu in (cmm) 152.2 (2,494)
6181.8 (2,979)
6
Maximum output
at engine speedhp (kW)
rpm184 (135)
6,000225 (165)
5,900
Maximum torque
at engine speedlb-ft (Nm)
rpm175 (237)
3,500214 (290)
3,500
Compression ratioe
10.5 10.2
Stroke
Borein (mm)
in (mm)2.95 (75)
3.31 (84)3.53 (89.6)
3.31 (84)
Fuel-injection system Digital-electronic engine-management system
Engine data