sensor BMW 325I 2001 User Guide

141n
IndexDataTechnologyRepairsCar careControlsOverview
Washing your vehicle You can wash your BMW at an auto-
matic car wash, even when it is new.
Brushless systems are preferable.
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 to 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.Turn the rain sensor off (refer to
page 69) when passing through an
automatic car wash. Failure to do so
could result in damage caused by unin-
tended wiper activation.<
Parts of the vehicle which are
inaccessible 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 ensure 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
surface. Inadequate distance and
excessive 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 clean by wiping with a dry 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 be corrode.<
Caring for your vehicle

144n
Caring for your vehicleCaring for the windowsYou 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
winter. 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 abrasives.
Do not use steam cleaners operating at
temperatures above +140 7 (+60 6).
Follow the manufacturer's instructions.
If your vehicle has chrome parts
*, such
as the window frames and door
handles, be especially careful about
cleaning them with plenty of water and
possibly a shampoo supplement as well
after the roads have been salted.
Use a chrome polish for an additional
treatment.
Plastic components, vinyl upholstery,
headliners, lamp lenses, the clear cover
of the instrument cluster and compo-
nents with a sprayed dull black surface
can be cleaned with water and a
synthetic cleaner (if necessary). Do not
allow moisture to soak through the
seats or headliner. 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.
Safety belts should be cleaned with a
mild soap and water solution without
being removed from the car. Never
attempt chemical or dry cleaning, as
damage to the belt fabric could result.
After cleaning, never allow the inertia
reel to retract the belts until they are
completely dry. Dirty safety belts pre-
vent 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
171n
IndexDataTechnologyRepairsCar careControlsOverview
Advanced technology:
Airbags172
Adaptive Transmission Control
(ATC)173
Automatic Stability Control plus
Traction ASC+T/Dynamic
Stability Control DSC173
Radio reception174
Four-wheel drive175
Safety belt tensioner175
Interior rearview mirror with
automatic dimmer176
Rain sensor177
Tire Pressure Control (RDC)178
Self-diagnostics179
Xenon lamps180
Technol-

172n
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 Head
Protection and side airbags in the front
or rear
* are triggered if necessary.
390de319
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 necessarily
accompanied by a certain amount of
ignition and inflation noise. The gas
required to inflate the airbags is not
dangerous, and the smoke associated
with it dissipates.
The entire process is completed within
fractions of a second.
Airbags

173n
IndexDataTechnologyRepairsCar careControlsOverview
On vehicles with an automatic trans-
mission, the Adaptive Transmission
Control (ATC) uses a number of factors
to calculate the gear which provides
maximum efficiency. In this process, it
considers your individual driving style
as well as current driving conditions.
ATC recognizes your personal driving
style from the positions and movements
of the accelerator pedal, deceleration
when braking, and lateral acceleration
through curves. Based on different shift
characteristics Ð from comfort-oriented
to performance-oriented Ð ATC will
select the appropriate gear.463us005
In order to include driving conditions in
its calculations, ATC registers curves
and both uphill and downhill gradients.
For example, if you maintain speed
through a curve, the transmission does
not shift up. On uphill gradients, it shifts
up only when the engine speed
increases in order to make more effi-
cient use of power reserves. On down-
hill gradients, ATC shifts down when
the speed of the vehicle increases and
the driver must apply the brakes.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 the wheel speeds
occur, ASC+T recognizes the danger of
wheelspin and reduces torque. If
necessary, the system also responds
with additional brake applications at the
rear wheels.
In addition, DSC permanently monitors
the vehicle's current operating condition
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. As a result, dangerous skids can
be prevented even as they are just
beginning.
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 sounds specific to the
system.
ATC
*
ASC+T/DSC
*

176n
Interior rearview mirror with automatic dimmer
*
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 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
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.

177n
IndexDataTechnologyRepairsCar careControlsOverview
Rain sensor
*
Depending on how wet the windshield
is, the rain sensor controls the opera-
tion 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 contributes to driving
safety and comfort.

178n
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 electronic chip which 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. 463de006
There is an antenna located right near
every wheel in the vehicle body. This
antenna picks up signals from its
respective wheel. A central electronics
system evaluates the quadruple signals
which it receives and forwards any
changes.
The RDC provides an important contri-
bution to driving safety.

Everything from A to ZFolding rear backrest108
Footbrake118
Footwell lamps88
bulb replacement158
Four-wheel drive175
Front fog lamps, bulb
replacement155
Front seat adjustment46
Frost protection,
radiator137
Fuel28
consumption77
consumption display74
gauge74
preparation184
quality28
Fuel filler door
releasing following an
electrical malfunction166
Fuel reserve indicator
lamp74
Fuel tank capacity187
Fuel tank gauge74
Functional status179
Fuses164 G
Gasoline28
Gasoline gauge74
Gasoline quality28
Glove compartment101 Glove compartment lamp,
bulb replacement158
Gross vehicle weight186
H
Handbrake63
Hands-free system103
Hazard warning flashers26
Hazard warning triangle26
Head restraint47
Headlamp covers,
care141,153
Headlamp flasher88
Headlamp washer
system70,134,187
Heated seats100
Heating, rapid94
Heavy loads110
Height185
HiFi system101
High beams23,68,88
bulb replacement153
High Performance Synthetic
Oils136
High-mount brake lamp157
Hood release130
Horn17
Hubcap160
Hydraulic Brake assistant,
refer to DBC118
I
Ice warning76
Icy roads76,121
Identification, tires127
Ignition key32,35
Ignition lock61
Imprint4
Indicator lamps20
Inflation pressure28,124
monitoring85,178
INSPECTION74
Installation child restraint
systems60
Instrument cluster18
Instrument lighting87
Interaxle tire rotation126
Interface socket for Onboard
Diagnostics149
Interference, cellular
phone123
Interior lamps36,88
bulb replacement158
remote control36
Interior motion sensor41
Interior rearview mirror51
automatic dimming
feature52,176
Interlock61
Intermittent wipe68
J
Jack159
Jump-starting167 K
Key32,35
Key Memory52 L
Lamps and bulbs153
Lashing eyes110
LATCH attachment of the
child seat58
Leather care145
Length185
License plate lamp
bulb replacement157
Light switch87
Light-alloy wheels129
Lighter104
Load-securing devices110
Louvers90,96
Low beam headlamps87
bulb replacement153
Lug bolts160
Lug wrench159

Everything from A to Z
195n
IndexDataTechnologyRepairsCar careControlsOverview
Luggage
compartment38,107
capacity186
emergency release166
lamps39
lamps, bulb
replacement158
remote control system37
trunk floor40
Luggage compartment lid
emergency release166
Luggage rack111
Lumbar support48 M
Maintenance74
Malfunction displays75
Manual transmission64
Memory49
MFL (Multifunction steering
wheel)24
Microfilter93,165
Mirror memory49
Mirrors51
Mobile phone123
Modifications,
technical6,148
Motion sensor, interior41
Multifunction steering wheel
(MFL)24
M+S tires128
N
Neckrest47
Nozzles96 O
OBD interface socket149
Obstruction protection43
Odometer73
Oil
additives135
capacity187
consumption135
dipstick135
quality136
specifications136
viscosity136
Oil change intervals, refer to
the Service and Warranty
Information Booklet or to
the Warranty and Service
Guide Booklet
Oil filter change187
Oil level, indicator lamp20
Oil pressure, indicator
lamp20
OILSERVICE74
Onboard computer, please
refer to Computer76
Onboard tool kit152
Opening and closing
from the inside38
from the outside34 Opening the rear
window40
Outside temperature
display76
Owner service
procedure141
P
Paint blemishes142
Paintwork
minor repairs143
waxing143
Paint, care142
Park Distance Control
(PDC)78
Parking brake63
Parking help78
Parking lamps88
Parking, winter122
Partition net107
PDC (Park Distance
Control)78
Performance184
Phone, mobile123
Pocket lamp101
Pollen93,100
Power outlet105
Power steering123
Power windows43
safety switch44
Pressure monitoring,
tires85,178
Pressure, tires28,124
Q
Quality Grades125 R
Radiator187
Radio
refer to the separate
Owner's Manual
Radio Data System
(RDS)174
Radio reception123,174
Rain sensor69,177
RDC (Tire Pressure
Control)85,178
RDS (Radio Data
System)174
Reading lamps88
Rear backrest, folded
down108
Rear hatch lamp
bulb replacement157
Rear lamps156
Rear seat backrest,
folding107
Rear window
defroster70,92,99
Rearview mirror51
Recirculated air control92
automatic99
Recirculated-air mode92
Reclining seat46
Refueling27