traction control BMW 325I 2001 User Guide

116n
Catalytic converter Antilock Brake System (ABS)
Be sure to observe the instruc-
tions above to prevent unburned
fuel from reaching the catalytic
converter, otherwise, the catalytic
converter could overheat and be
damaged.
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 care to avoid
contact between the exhaust system
and flammable materials (grass, hay,
leaves etc.). Such contact could lead to
a fire, resulting in personal injury and
property damage.<
The concept ABS enhances active driving safety by
helping to prevent the wheels from
locking under braking. The reason:
locked wheels are dangerous. When the
front wheels slide, the driver loses
steering control over the vehicle. Trac-
tion loss at the rear wheels can cause
the rear end to break into an uncon-
trolled skid.
The system can achieve the shortest
braking distances possible under most
conditions (on straight-aways and in
curves, on asphalt, ice, wet road
surfaces, etc.).
ABS is designed to meet two essential
requirements during every brake appli-
cation:
>To help provide vehicle stability.
>Assured ability to steer and
maneuver Ð on the various road
surfaces (asphalt, concrete, dirt,
wet conditions, snow, ice).
The system can achieve the shortest
braking distances possible under most
conditions (on straight-away and in
curves, on asphalt, ice, wet road
surfaces, etc.).
Braking with ABSThe system is operative once the
vehicle exceeds a speed of approx.
6 mph (10 km/h). It is deactivated once
again below approx. 4 mph (6 km/h).
This means that the wheels can lock in
the final phase of a panic stop Ð a factor
of no significance in actual use.
If you are in a situation that requires full
braking, you will exploit the full benefits
of the ABS system if you apply
maximum brake pressure ("panic
stop"). Since the vehicle maintains
steering responsiveness, you can
nevertheless avoid possible obstacles
with a minimum of steering effort.
The ABS closed-loop control circuit
cycles in fractions of a second. A pulsa-
tion at the brake pedal, together with
the sounds associated with the
hydraulic controls, tells you that the
brake system is within its maximum
limit range, and reminds you that you
should adapt road speed to the road
conditions.
On road surfaces that have a loose
surface layer on a firm base with good
traction (on gravel or snow, for
example), or when snow chains are
mounted, braking distances may be
longer than with locked wheels.

121n
IndexDataTechnologyRepairsCar careControlsOverview
Winter operationWinter is often accompanied by rapid
changes in weather. Adaptions in
driving style should be accompanied by
preparations on the vehicle itself to
ensure that your vehicle operates safely
and trouble-free throughout the winter
months.CoolantBe sure that the coolant mixture
contains the year-round ratio of 50:50
water and antifreeze/corrosion protec-
tion. This mixture will resist freezing to
approx. Ð34 7 (Ð37 6). Replace the
coolant every four years.LocksBMW door lock deicer can be used to
free them if frozen. This deicer also
contains lubricant.
After using the deicer, treatment with
BMW lock cylinder grease is recom-
mended.
Rubber seals and components To prevent the weather stripping from
freezing, apply a spray-on rubber treat-
ment or silicone spray to the door, hood
and tailgate seals.
A full range of car care products is
available from your BMW center. *
BMW snow chains can be mounted on
both summer and winter tires. Mount
them in pairs on the rear wheels only
and comply with the manufacturer's
safety precautions. Do not exceed a
maximum speed of 30 mph (50 km/h).
In this type of exceptional situation
where the snow chains are mounted,
deactivate the ASC+T/DSC. Refer to
page 79.
BMW 325xi: in a worst-case scenario,
i.e. if your vehicle is stuck on one side
or you cannot access one tire, then only
one chain may be attached to a rear
wheel for a short period of time.
Starting offWhen starting off from a full stop in
deep snow or when "rocking" the
vehicle to free it, it may be effective to
deactivate the ASC+T/DSC system for
a short period. Refer to page 79.Driving on low-traction road
surfacesUse smooth, gentle pressure to control
the accelerator pedal. Avoid excessive
engine speeds and shift to the next
higher gear at an early point. Downshift
into the next lower gear on ascents or
descents. Maintain an adequate
distance between yourself and the
vehicle ahead.

122n
Winter operationBrakingWinter road conditions substantially
reduce the amount of traction available
between the tires and the road surface.
Keep this in mind, because the braking
distance increases substantially.
ABS is intended to prevent the wheels
from locking during brake applications,
thus helping to maintain vehicle stability
and steering response.
If the ABS does not respond in a critical
braking situation and the wheels lock:
reduce the pressure on the brake pedal
until the wheels just start to roll again
while still maintaining enough force to
continue braking.
Then increase the pressure, reduce the
pressure when the wheels lock, reapply
pressure etc.
This staggered braking procedure will
reduce braking distances while helping
you maintain steering control.
You can then attempt to steer around
hazards after you have reduced pres-
sure on the brake pedal.Do not shift down on slick road
surfaces Ð if you want to decel-
erate. Doing so could cause the rear
wheels to lose traction and skid, which
could result in the loss of vehicle
control.<
Depress the clutch during hard
braking on road surfaces that
provide only poor or uneven traction.<
Skid control Depress the clutch and release the
accelerator pedal, or place the selector
lever of the automatic transmission into
the "Neutral" position. Countersteer
carefully and attempt to regain control
of the vehicle.
ParkingEngage 1st or reverse gear. If your
vehicle is equipped with an automatic
transmission, place the selector lever in
"Park." On vehicles with manual trans-
mission, also apply the parking brake
when parking on inclined surfaces. In
order to prevent the parking brake pads
from locking due to frost or corrosion,
dry them by gently applying the parking
brake as the vehicle is coming to a
stop. Make sure that following traffic
is not endangered.
The brake lamps do not come
on when the parking brake is
applied.<

125n
IndexDataTechnologyRepairsCar careControlsOverview
To maintain good handling and vehicle
response, use only tires of a single
tread configuration from a single manu-
facturer. BMW tests and approves
wheel/tire combinations. Refer to
page 129.DOT Quality GradesTreadwear
Traction AA A B C
Temperature A B C
All passenger car tires must
conform to Federal Safety
Requirements in addition to these
grades.< Tread wearThe tread wear grade is a comparative
rating based on the wear rate of the tire
when tested under controlled condi-
tions on a specified government test
course.
For example, a tire graded 150 would
wear one and one-half (1g) times as
well on the government course as a tire
graded 100. The relative performance
of tires depends upon the actual condi-
tions of their use, however, and may
depart significantly from the norm due
to variations in driving habits, service
practices and differences in road char-
acteristics and climate.
TractionThe traction grades, from highest to
lowest, are AA, A, B, and C.
Those grades represent the tire's ability
to stop on wet pavement as measured
under controlled conditions on speci-
fied government test surfaces of asphalt
and concrete. A tire marked C may have
poor traction performance.
The traction grade assigned to
this tire is based on straight-
ahead braking traction tests, and does
not include acceleration, cornering,
hydroplaning, or peak traction charac-
teristics.< TemperatureThe temperature grades are A (the
highest), B, and C, representing the
tire's resistance to the generation of
heat and its ability to dissipate heat
when tested under controlled condi-
tions on a specified indoor laboratory
test wheel.
Sustained high temperature can cause
the material of the tire to degenerate
and reduce tire life, and excessive
temperature can lead to sudden tire
failure. The grade C corresponds to a
level of performance which all
passenger car tires must meet under
the Federal Motor Vehicle Safety Stan-
dard No. 109. Grades B and A repre-
sent higher levels of performance on
the laboratory test wheel than the
minimum required by law.
The temperature grade for this tire
is established for a tire that is
properly inflated and not overloaded.
Excessive speed, under-inflation, or
excessive loading, either separately or
in combination, can cause heat buildup
and possible tire failure.< Uniform Tire Quality Grading Quality grades can be found where
applicable on the tire sidewall between
tread shoulder and maximum section
width. For example:
Tread wear 200 Traction AA
Temperature A
Do not use retreaded tires. Driving
safety may be impaired by their
use. This is due to the possible varia-
tions in casing structures and, in some
cases, to their extreme age, which can
lead to a decrease in their durability.<
Tire replacement

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-

175n
IndexDataTechnologyRepairsCar careControlsOverview
Four-wheel drive Safety belt tensionerThe transmission of power to the four
drive wheels is provided permanently
through a transfer box. The distribution
of torque between the front and rear
axles is 38% to 62%.
Traditional differential locks at the front
and rear axles and in the transfer box
are not required. Their function is
assumed by automatic braking inter-
vention at all four wheels. These trac-
tion interventions are governed by
Automatic Differential Brake (ADB-X), a
sub-function of DSC.
If a wheel tends to slip, it is braked
automatically by ADB-X until it once
again gains traction, and drive force
can be transmitted to that wheel. In
addition, the drive force is distributed to
the remaining wheels during this 530us133
system intervention. Engine output is
also reduced if necessary.
When the DSC is deactivated, the
ADB-X traction intervention is set for
the maximum drive force. However, the
engine intervention and the stability
controls are no longer available. For
this reason, DSC should only be deacti-
vated in the exceptional circumstances
described on page 81.
The BMW 325xi is not an off-road
vehicle. Instead, permanent four-wheel
drive provides a high degree of vehicle
stability and tractive ability under all
road conditions, and will aid you in crit-
ical driving situations, e. g. driving in
extreme winter conditions or on loose
road surfaces.The safety belt tensioner responds to
severe frontal 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
shoulder and lap belts within fractions
of a second. This reduces the tendency
to slide under the lap belt.
390de330

Everything from A to ZA
ABS (Antilock Brake
System)22,116
Accessories6
Activated-charcoal
filter100,165
Adaptive Transmission
Control (ATC)65,173
Adding engine oil135
Adding washer
fluid134,187
Adjust
backrest47
steering wheel50
temperature92
thigh support area48
Air conditioner90
Air distribution92,98
Air nozzles90
Air outlets96
ventilation90,96
Air pressure124
Air supply92,99
Airbags21,58,147,172
Alarm system41
Antenna123
Antenna Diversity174
Antifreeze137
radiator121
Antilock Brake System
(ABS)22,116
Anti-theft alarm system41
Aquaplaning115,124 Armrest102
ASC+T (Automatic Stability
Control plus
Traction)22,173
Ashtray104
ATC (Adaptive Transmission
Control)65,173
Attaching vacuum
cleaner104
AUC (Automatic climate
control)96
Automatic car washes141
Automatic climate
control96
remove condensation from
the windows98
Automatic cruise control71
Automatic dimming, interior
rearview mirror52
Automatic Stability Control
plus Traction
(ASC+T)22,173
Automatic transmission21
Automatic transmission with
Steptronic65
Automatic washer
rear window69
windshield69
Average consumption77
Average speed77
Axle loads186
B
Backrest, adjusting47
Backup lamps64
bulb replacement156
Battery162,188
capacity188
charging164
discharged167
removal and
installation163
Battery charge current20
Battery safety terminal163
Belts53
Beverage holder102
Blower92,99
BMW High Performance
Synthetic Oils136
BMW sports seat48
Bore184
Brake
fluid138
hydraulic system20
pads22
Brake lamps
bulb replacement156
Brake system118
faults120
Break-in procedure114
Bulb replacement153
Bulbs and lamps153
C
California Proposition
65 Warning148
Capacities187
Car Memory52
Car radio123
reception174
refer also to the separate
Owner's Manual
Car telephone103
Car vacuum cleaner,
connecting104
Car wash141
Care
upholstery145
vehicle exterior142
vehicle finish143
vehicle interior144
wool velour145
Cargo loading110
Catalytic converter115
CBC (Cornering Brake
Control)21,117
Cellular phone123
refer to the separate
Owner's Manual
Center armrest102
Center (high-mount) brake
lamp157
Central locking system34
button38
Changing a tire159

Everything from A to Z
197n
IndexDataTechnologyRepairsCar careControlsOverview
Tire codes127
Tire damages124
Tire inflation
pressure28,124
Tire Pressure Control
(RDC)85,178
Tire pressure
monitoring85,178
Tire Quality Grading125
Tire replacement125,126
Tire specifications129
Tire tread124
Tools152
Torque184
Tow fittings168
Tow starting168
Towing168
Track185
Traction Control System,
refer to DSC79
Transmission64
Transporting children
safely58
Tread depth, tires124
Trip odometer73
Trunk38
Turn signal
indicator23,68,154
bulb replacement154
Turning radius185
Two-way radios123
U
Uniform Tire Quality
Grading125
Used batteries164 V
Vacuum cleaner,
connecting104
Vanity mirror51
bulb replacement158
Vehicle battery162,188
Vehicle care
exterior142
interior144
Vehicle Identification
Number (VIN)139
Vehicle immobilizer33
Vehicle painting142
Vehicle removal from
service147
Vehicle storage147
Vehicle weight186
Ventilation90,93,96
draft-free93,100
Vinyl upholstery, care144
Voice recognition24,25 W

Warning lamps20
Warning messages75
Warranty and Service Guide
(Canadian models)140 Washer fluids134
Washer nozzles134
Washer reservoir, filling134
Washing your car141
Water on roadways
deep water115
Waxing, paintwork143
Weights186
Wheel changing159
Wheel lug wrench159
Wheel rims127
Wheel stud wrench159
Wheelbase185
Wheels and tires127,129
Width185
Windows, convenience
operation34
Windshield washer nozzle
adjustment134
Windshield washer reservoir,
filling134,187
Windshield wiper68
blade replacement152
Winter operation121
Winter tires127,128
Wiper blade
replacement152
Wiper system68
Work in the engine
compartment130
X
Xenon lamp154,180