2001 BMW 325i SEDAN traction control

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IndexDataTechnologyRepairsCar careControlsOverview
DSC
* Ð BMW 320i, 325i, 330i
Switch the DSC and ADB offHold the DSC button down for at least
3 seconds. The indicator and the yellow
brake warning lamps will remain on the
entire time.
In this case, no interventions to
increase stability and traction for engine
and brakes are carried out.
To maintain vehicle stability,
always drive with the DSC on
whenever possible.<
Switch the DSC and ADB back onPress the button again; the indicator
lamp or the indicator lamps will go out.
The laws of physics cannot be
repealed, even with DSC. It will
always be the driver's responsibility to
drive in a manner that matches road
conditions. We therefore urge you to
avoid using the additional safety margin
of the system as an excuse for taking
risks.
Whenever the ADB has been activated,
the DSC is switched off and will not
perform any stabilizing intervention.
Do not make any modifications to the
DSC system. Allow only authorized
technicians to perform work on the
DSC.<
For additional details concerning DSC,
please refer to the chapter "Advanced
technology" on page 179.

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DSC Ð BMW 325xi, 330xiThe conceptDSC maintains vehicle stability, even in
critical driving situations.
The system enhances vehicle stability
during acceleration and when starting
up from a full stop, and optimizes trac-
tion as well. In addition, it recognizes
unstable vehicle conditions, such as
understeering or oversteering, and, as
far as is possible within the laws of
physics, helps keep the car on a steady
course by reducing the RPMs and
brake applications to the individual
wheels.
The DSC is operational every time you
start the engine. DSC contains the
functions of ADB-X and CBC, refer to
page 119.
The ADB-X (automatic differential
braking) replaces the function of
conventional differential and transverse
lock through brake intervention, and
increases traction whenever conditions
merit, e. g. when driving on snow-
covered roads.Indicator lamp
The indicator lamp in the instru-
ment cluster goes out shortly
after you switch on the ignition.
Refer to pages 21, 22.
Indicator lamp flashes:
DSC controls the drive and braking
forces.
Indicator lamp lights up permanently:
DSC has been switched off via the
button; ADB-X is operational.
ADB-X intervention is not indicated.
If the warning lamp does not go
out after pressing the DSC button
repeatedly, then both the DSC and
ADB-X are defective. Consequently,
interventions to increase driving
stability (as described in the preceding
column) are not available.<
You can drive perfectly well without
DSC. Please contact your BMW center
in the event of a fault, refer to
pages 21, 22.
Switching the DSC offPress the DSC button; the indicator
lamp comes on and stays on.
The DSC has been switched off and the
ADB-X is designed for maximum
output.
In the following exceptional circum-
stances, it may be effective to deacti-
vate the DSC for a short period:
>When rocking the vehicle or starting
off in deep snow or on loose surfaces
>When driving with snow chains.
Refer also to page 122.
To maintain vehicle stability,
always drive with the DSC on
whenever possible.<460de313

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To ensure that your vehicle provides
maximum economy throughout a long
service life, we request that you comply
with the following recommendations.
Engine and differentialUp to 1,200 miles (2,000 km):
Drive at varying engine speeds and
road speeds, but do not exceed
4,500 RPM or a road speed of 100 mph
(160 km/h) during this initial period.
Obey your local and state maximum
speed limits.
Do not apply full throttle and avoid
pressing the accelerator beyond the
kickdown point.
After 1,200 miles (2,000 km), you can
gradually increase the engine speed or
road speed.
Follow the same break-in procedure if
either the engine or the differential is
replaced in the future.
TiresDue to technical factors associated
with their manufacture, tires do not
achieve their full traction potential until
an initial break-in period has elapsed.
For this reason, drive cautiously during
the first 200 miles (300 km).
Obey your local and state maximum
speed limits.
When the vehicle is operated on
wet or slushy roads, a wedge of
water may form between the tire and
the road surface. This phenomenon is
referred to as aquaplaning, or hydro-
planing, and can lead to partial or
complete loss of traction, vehicle
control and braking effectiveness.
Reduce your speed on wet roads.<
Brake systemBrake pads and disks do not attain their
optimal wear patterns until after approx.
300 miles (500 km).
To break-in the separate parking brake
drums, apply the parking brake lightly
when coasting to a standstill (at a traffic
signal, for instance), provided that
traffic conditions allow you to do so.
To avoid corrosion, repeat this proce-
dure from time to time.
The brake lamps do not come on
when the parking brake is set.
Vacuum for the brake system servo unit
on your BMW is available only when the
engine is running. When you move the
vehicle with the engine off Ð when
towing, for example Ð substantially
higher levels of pedal force will be
required to brake the vehicle. optimally after about 300 miles
(500 km). Engage the gears carefully
during the break-in period.
Break-in procedures

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Catalytic converter Antilock Brake System (ABS)
Be sure to comply with the
instructions above to prevent
unburned fuel from reaching the cata-
lytic convertor. If you do not, the cata-
lytic converter could respond by
overheating, leading to serious
damage.
Extreme temperatures occur at the
catalytic converter on this and every
catalyst-equipped vehicle. Heat shields
are installed adjacent to some sections
of the exhaust system. Never remove
these shields; do not apply under-
coating to their surfaces. When driving,
standing at idle, and parking the
vehicle, take extra care to avoid contact
between the exhaust system and flam-
mable materials (grass, hay, leaves,
etc.). Such contact could lead to a fire,
resulting in serious personal injury and
property damage.<
The concept ABS enhances active safety by helping
to prevent the wheels from locking
under braking. This is because locked
wheels are dangerous. When the front
wheels slide, the driver loses steering
control over the vehicle. Traction loss at
the rear wheels can cause the rear end
to break into an uncontrolled 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
>To help maintain steering control and
maneuverability Ð on all types of road
surfaces (asphalt, concrete, mud, wet
road surfaces, snow, ice).Braking with ABSThe system becomes operative once
the vehicle exceeds a speed of approx.
6 mph (10 km/h). Below approx. 4 mph
(6 km/h), it is once again deactivated.
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 avoid
possible obstacles with a minimum of
steering effort, despite the full brake
application.
The ABS system closed-loop control
circuit cycles in fractions of a second. A
pulsation 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.
However, ABS continues to provide
enhanced vehicle stability and steering
response under these conditions.
Information for your safetyNot even ABS can suspend the laws of
physics. ABS cannot prevent the

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Winter operationThe onset of winter is often accompa-
nied by rapid changes in weather.
Adaptations in driving style should be
accompanied by preparations on the
vehicle itself to ensure that your
progress through the winter remains
safe and trouble-free.CoolantBe sure that the coolant mixture
contains the year-round ratio of 50:50
water and extended-duty antifreeze/
corrosion protection. This mixture
provides protection against freezing
down to approx. -34 7 (-37 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 its use, treatment with BMW lock
barrel grease is recommended.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 luggage compartment lid seals.A full range of car care products is
available from your BMW center.<
Snow chains 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 situation, it may be appropriate
to deactivate the ASC+T/DSC for a
short period of time. Refer to page 80.
BMW 325xi, 330xi: in a worst-case
scenario, if your vehicle is stuck on one
side or you cannot access one tire, then
a chain may be attached to one rear
wheel for a short period of time.Starting offWhen starting from a full stop in deep
snow or for "rocking" the vehicle to free
it, it may be effective to deactivate the
ASC+T/DSC system. Refer to page 80.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. On down-
grades or slopes, shift down to the next
lower gear at an early point. Maintain an
adequate distance between yourself
and the vehicle ahead.BrakesWinter road conditions substantially
reduce the traction available between
the tires and the road surface.
Remember that braking distances will
be significantly longer as a result.
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.
Following that, increase pedal pressure
again. Reduce the pressure as the
wheels lock, then reapply pressure.
Repeat this procedure. This type of
staggered braking will reduce the
braking distance, and the vehicle still
remains responsive to steering. It allows
you to steer around hazards once you
have reduced the pressure on the brake
pedal.

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IndexDataTechnologyRepairsCar careControlsOverview
Winter operation Power steering
Do not shift down on slick road
surfaces. Doing so could cause
the rear wheels to lose traction and
skid, resulting in a 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
linings 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 light up
when the parking brake is
applied.<
If the steering response changes, e.g.
high steering effort:
Contact a BMW center to have this
system inspected.
If the power steering fails,
increased effort will be required to
steer the vehicle.<

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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, beginning on
page 130.
DOT Quality GradesTreadwear
Traction AA A B C
Temperature A B C
All passenger vehicle tires must
conform to Federal Safety
Requirements in addition to these
grades. 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. 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 vehicle tires must meet
under the Federal Motor Vehicle Safety
Standard No. 109. Grades B and A
represent 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, underinflation, or
excessive loading, either separately or
in combination, can cause heat buildup
and possible tire failure. applicable on the tire sidewall between
tread shoulder and maximum section
width. For example:
Treadwear 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, factors that
can lead to a decrease in their dura-
bility.<
Tire replacement

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IndexDataTechnologyRepairsCar careControlsOverview

Winter tires

Choosing the right tire

BMW recommends winter tires (M+S
radial tires) for driving in adverse winter
road conditions. Although all-season
M+S tires provide better winter traction
than standard summer tires with H, V,
W, Y and ZR speed ratings, they gener-
ally fail to provide the same levels of
performance as standard snow tires in
winter driving.
In the interest of safe tracking and
steering response, install winter tires
made by the same manufacturer having
the same tread configuration on all four
wheels.
Mount only winter tires approved by
BMW. Any BMW center will be glad to
provide you with information on the
best winter tires for your particular
driving conditions.

Do not exceed specified
maximum speeds

Never exceed the maximum speed
for which the tires are rated.
Unprofessional attempts by laymen to
service tires can lead to damage and
accidents.
Have this work performed by skilled
professionals only. Any BMW center
has the required technical knowledge
and the proper equipment and will be
happy to assist you.

<

Tire condition, tire pressure

Winter tires display a perceptible loss in
their ability to cope with winter driving
conditions once the tread wears to
below 0.16 inches (4 mm), and should
thus be replaced.
Comply with the specified tire inflation
pressures Ð and be sure to have the
wheel and tire assemblies balanced
every time you change the tires.

Storage

Always store tires in a cool, dry place.
Store them away from light whenever
possible. Protect the tires against
contact with oil, grease and fuel.

Snow chains

*
The use of narrow-link BMW snow
chains on winter tires is approved only
in pairs and only on the rear wheels.
BMW 325xi, 330xi: in a worst-case
scenario, if your vehicle is stuck on one
side or you cannot access one tire, then
a chain may be attached to one rear
wheel for a short period of time.
Comply with all manufacturer's safety
precautions when mounting the chains.