2001 BMW 325Ci CONVERTIBLE sensor

103n
IndexDataTechnologyRepairsCar careControlsOverview
Automatic climate control
*
1 Air onto the windshield and onto the
side windows
2 Air for the upper body area
The side rotary dials open and close
the air supply through an infinitely-
variable range; the levers will
change the direction of the air flow.
The center rotary dial adjusts the
temperature of the air as it flows
out, see page 106
3 Air for the front footwell
There are vent outlets for the foot-
well in the rear as well
4 Recirculated air mode/Automatic
recirculated air control (AUC)105
5 Air supply105
6 Temperature104
7 Automatic air distribution104
8 Individual air distribution104
9 Air grill for interior temperature
sensor Ð please keep clear and
unobstructed
10 Display for temperature and air
supply104
11 Defrost windows and remove
condensation105
12 Air conditioner105
13 Rear window defroster78, 106

121n
IndexDataTechnologyRepairsCar careControlsOverview
Brakes:
Do not drive with your foot resting
on the brake pedal. Even light but
consistent pedal pressure can lead to
high temperatures, brake wear, and
possibly to brake failure.
Aquaplaning:
When driving on wet or slushy roads,
reduce vehicle speed. If you do not, a
wedge of water may form between the
tires and the road surface. This
phenomenon is referred to as aqua-
planing or hydroplaning. It is character-
ized by a partial or complete loss of
contact between the tires and the road
surface. The ultimate results are loss of
steering and braking control.
Driving through water:
Do not drive through water on the road
if it is deeper than 1 ft (30 cm), and then
only at walking speed. Otherwise, the
vehicle's engine, the electrical systems
and the transmission may be damaged.
Clothes hooks (for the hardtop):
When suspending clothing from the
hooks, be sure that they will not
obstruct the driver's vision. Do not hang
heavy objects on the hooks. If you do
so, they could cause personal injury
during braking or evasive maneuvers.<
The catalytic converter reduces harmful
exhaust emissions.
It is designed for use with unleaded fuel
only. Even minute quantities of lead
would be enough to permanently
damage both the catalytic converter
and the system oxygen sensor.
To ensure efficient, trouble-free engine
operation and to avoid potential
damage:
>Be sure to comply with the scheduled
maintenance requirements.
>Fill the fuel tank well before it is
empty.
>Tow-start only when the engine is
cold. If you attempt to tow-start with
a warm engine, unburned residual
fuel in the catalytic converter could
ignite and cause damage. It is better
to jump-start the vehicle with outside
assistance.
>Avoid other situations in which the
fuel is not burned, or burns incom-
pletely, such as engaging the starter
frequently or for extended periods, or
repeated start attempts in which the
engine does not start (stopping and
restarting an engine which is running
properly does not present a problem).
Never allow the engine to run with
any of the spark plug cables discon-
nected.Be sure to comply with the
preceding instructions to prevent
unburned fuel from reaching the cata-
lytic converter. If you do not, the cata-
lytic converter could respond by
overheating, leading to serious
damage.
Very high temperatures occur in any
vehicle equipped with a catalytic
converter. Heat shields are installed
adjacent to some sections of the
exhaust system. Never remove these
shields; do not apply undercoating to
their surfaces. When driving, standing
at idle, and parking the vehicle, take
extra care to avoid contact between the
exhaust system and flammable mate-
rials (grass, hay, leaves, etc.). Such
contact could lead to a fire, resulting in
serious personal injury and property
damage.<
Driving notes Catalytic converter

151n
IndexDataTechnologyRepairsCar careControlsOverview
Washing your vehicle You can have your BMW washed in
an automatic car wash, even when it
is new. Car wash systems that do not
employ brushes are preferable, refer to
page 157.
Wipe away tough dirt and loosen and
remove dead insects before washing
the vehicle.
In order to avoid spots, do not wash the
vehicle when the hood is warm, or
during or immediately after exposure to
strong sunlight.
When using an automatic car wash, be
sure that:
>The car wash system is suited for the
dimensions of your vehicle.
>No damage will occur on vehicles
with attached body accessories (such
as spoilers or antennas). Consult the
car wash operator if necessary.
>The wheels and tires of your vehicle
cannot be damaged by the convey-
ance devices of the car wash system.
>The vehicle is cleaned with minimum
brush pressure, and that ample water
is available for washing and rinsing.Vehicles with rain sensor:
Clean the windshield regularly. Wax
from automatic car washes or insects
can cause malfunctions in the function
of the rain sensor.
Deactivate the rain sensor when
going through car washes (refer to
page 77) Ñ otherwise, the wipers could
be damaged if they inadvertently start
working.<
Parts of the vehicle that are inaccessi-
ble to the automatic washer Ð such as
door sills, door and hood edges, etc. Ð
should be cleaned by hand.
In the winter months, it is especially
important to be sure that the vehicle is
washed on a regular basis. Large quan-
tities of dirt and road salt are difficult to
remove, and they also damage the
vehicle.
If spray wands or high-pressure
washers are used, be sure to
maintain an adequate distance between
the spray source and the vehicle's sur-
face. Inadequate distance and exces-
sive pressure can damage or weaken
the finish, making it more susceptible to
subsequent attack. In addition,
moisture could penetrate to vehicle
components, leading to long-term
damage.<
When cleaning the headlamps,
please observe the following: do
not wipe dry with a cloth (scratches).
Never use abrasives or strong solvents
to clean the covers. Remove dirt and
contamination (such as insects) by
soaking with BMW Car Shampoo and
then rinsing with plenty of water.
Always use a deicer spray to remove
accumulated ice and snow Ð never use
a scraper.<
After washing the vehicle, apply
the brakes briefly to dry them.
Braking efficiency might otherwise be
reduced by the moisture and the brake
rotors could also be corroded.<
Caring for your vehicle

154n
Caring for your vehicleWindow careYou can use window and glass cleaner
to clean inside window surfaces and
mirrors without smearing and streaking.
Never use polishing pastes or abrasive
(quartz) cleansers on mirror lenses.
Clean the wiper blades with soapy
water. The wiper blades should be
replaced twice a year Ð before and after
the winter months. This is especially
important for vehicles with a rain
sensor.
Use only wiper blades approved
by BMW.<
Caring for other vehicle
components and materials Light-alloy wheels should be treated
with alloy wheel cleaner, especially
during the winter months. However, do
not use aggressive products contain-
ing acids, strong alkalis or abrasive
cleaning agents, nor steam cleaners
operating at temperatures above
140 7 (+60 6) (follow the manufac-
turer's instructions).
If your vehicle has chrome parts
*, such
as the window frames and door handles,
clean these parts carefully with ample
clean water and a shampoo supplement
if desired, especially if they have an
accumulation of road salt. Use a chrome
polish for an additional treatment.
Plastic components, vinyl upholstery,
headliners (hardtop), lamp lenses, the
clear cover of the instrument panel and
components with a sprayed dull black
surface can be cleaned with water (add
plastic shampoo as required). Do not
allow moisture to soak through the
seats or headliner (hardtop). Never use
solvents such as lacquer thinner,
heavy-duty grease remover, fuels, or
similar substances. Rubber components should be cleaned
with water only; a rubber treatment or
silicone spray may also be applied.
Do not remove safety belts to clean
them. Clean them with mild soapy
water only. Do not use chemicals or dry
cleaners to clean safety belts, since this
could damage the belt fabric.
After cleaning, never allow the inertia
reel to retract the belts until they are
completely dry. Dirty safety belts
prevent the inertia reel mechanism from
retracting the strap properly, and thus
constitute a safety hazard.
Heavily soiled floor carpets and mats
*
can be cleaned with an interior cleaner.
The floor mats can be removed from
the vehicle for cleaning.
Use only a damp cloth to clean trim
panels made of real wood
* and other
parts constructed of real wood
*. Follow
up by drying with a soft cloth.
Use the cleaning and car-care
products available at your BMW
center.<

Overview
Controls and features
Operation, care
and maintenance
Owner service procedures
Technical data
Index Advanced technology
187n
IndexDataTechnologyRepairsCar careControlsOverview
Adaptive Transmission Control
(ATC)188
Airbags189
Automatic Stability Control plus
Traction (ASC+T)/Dynamic
Stability Control (DSC)189
Radio reception190
Safety belt tensioner190
Interior rearview mirror
with automatic dimming
feature191
Rain sensor191
Tire Pressure Control (RDC)192
Self-diagnostics192
Rollover protection system193
Xenon lamps193
Technol-

189n
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 side
airbags in the front and/or rear
* are
triggered if necessary.
390de012
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. Dangerous skids are
thus prevented before they can even
start, and all of this is possible, of
course, only within physically possible
limits. You may need some time to
become accustomed to the system's
intervention. 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
*

191n
IndexDataTechnologyRepairsCar careControlsOverview
Interior rearview mirror with automatic dimming feature
* Rain sensor
*
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.46cus036
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.
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 windshield 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 quantity of reflected light is thus a
means of gauging the degree of wetness
on the windshield. When the system is
set to the "Intermittent" 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 contri-
bution to driving safety and comfort.
390de133

192n
Tire Pressure Control* Self-diagnostics 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.
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.46cde078
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 brießy
after the ignition has been turned on, for
example.
While you are driving, the functional
status of the actuator motors (for the
windshield wipers, power windows,
seats, etc.) is constantly being analyzed
by electrical measurements in the relays.
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 ßuctuation that 46cde052
would necessarily accompany 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 ßaps of
the heating and ventilation system travel
to the nearest limit position. This action
ensures that the system will be able to
provide defrosting, regardless of other
circumstances, e. g. if a malfunction in the
air conditioner/automatic climate control
system
* should occur during the night
while the vehicle is parked.
A calibration cycle runs every tenth time
the engine is shut off. During this cycle,
the actuator motors of all the heating and
ventilation ßaps 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 appro-
priate adjustments for the operating
elements can be made at any time.
You will hear the sounds of the air ßaps 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 func-
tions operate silently in the background.
Any possible faults detected during these
self-diagnostics can be read out and
corrected by your BMW center
during the
next regularly scheduled maintenance.