2001 BMW 325i SEDAN Owner's Manual

185n
IndexDataTechnologyRepairsCar careControlsOverview
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 "Intermit-
tent" 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.

186n
Tire Pressure Control (RDC)
*
This system regularly checks tire pres-
sure and monitors all four tires even
while driving, so you don't have to.
Behind the valve stem in every wheel,
there is an electronic chip that is
designed for severe-duty applications
and long service life. It contains a pres-
sure 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. 460de169
Near every wheel is an antenna in the
body that receives the signal 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.

187n
IndexDataTechnologyRepairsCar careControlsOverview
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 also 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 analyzed by current
measurements in their relays.460de177
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 ensures that the defrost func-
tion is always available even if a
malfunction in the air conditioner
system/automatic climate control
should occur while the vehicle is
parked overnight, for instance.
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 posi-
tions 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 conditioning system/auto-
matic climate control carry out their
self-diagnostic functions after the igni-
tion has been turned off. All of the other
self-diagnostics functions operate
silently in the background.
Any possible faults detected during
these self-diagnostics can be read out
by your BMW center during the next
regularly-scheduled maintenance and
corrected with a minimum of time.

188n
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 driving
situations, (driving at night in heavy rain
or through road repair areas where
there are no lane markers, for instance).
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 condi-
tions, and drivers in oncoming traffic
are not blinded.
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.

189n
IndexDataTechnologyRepairsCar careControlsOverview

190n

Overview
Controls and features
Operation, care
and maintenance
Technical data
Index Advanced technology
191n
IndexDataTechnologyRepairsCar careControlsOverview
Engine data192
Dimensions193
Weights194
Capacities195
Electrical system196
V-belts196
Data
Owner service procedures

192n
BMW 320i BMW 325i/325xi BMW 330i/330xi
Displacement
Number of cylinders cu in (ccm) 132.5 (2,171)
6152.2 (2,494)
6181.8 (2,979)
6
Maximum output
at engine speed hp (kW)
rpm168 (124)
6,250184 (135)
6,000225 (165)
5,900
Maximum torque
at engine speedlb ft (Nm)
rpm155 (210)
3,500175 (237)
3,500214 (290)
3,500
Compression ratioe
10.8 10.5 10.2
Stroke
Borein (mm)
in (mm)2.83 (72)
3.15 (80)2.95 (75)
3.31 (84)3.53 (89.6)
3.31 (84)
Fuel-injection system Digital electronic Engine-Management System
BMW 325xi, 330xi: an engine performance test is authorized only on a suitable chassis dynamometer.
Engine data