traction control BMW Z3 2002 User Guide

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Pages: 187, PDF Size: 2.73 MB

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Page 101 of 187

BMW Z3 2002 User Guide 101n
IndexDataTechnologyRepairsMaintenanceControlsOverview
Antilock Brake System (ABS)The conceptThe Antilock Brake System (ABS) keeps
the wheels from locking during braking,
thereby enhancing activ

101n
IndexDataTechnologyRepairsMaintenanceControlsOverview
Antilock Brake System (ABS)The conceptThe Antilock Brake System (ABS) keeps
the wheels from locking during braking,
thereby enhancing active driving safety.
The reason: 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 or in
curves, on the various road surfaces).
ABS is designed to meet two essential
requirements during every brake appli-
cation:
>To help provide vehicle stability
>Assured ability to steer and maneuver
on the various road surfaces (asphalt,
concrete, dirt, wet conditions, snow
and ice).
Braking with ABSThe system is operative once the
vehicle exceeds a speed of approx.
6 mph (10 km/h). It is inactive once
again below approx. 4 mph (6 km/h).
Therefore, the wheels could theoreti-
cally tend to lock in the final phase of a
braking action, but this is insignificant in
actual practice.
If you are in a situation which 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 closed-loop control circuit
cycles in fractions of a second. The
pulsation at the brake pedal, together
with sounds generated by the hydraulic
control system, indicate to you that the
vehicle is approaching its maximum
braking range. It is a reminder to you
that you must adapt the vehicle's road
speed to existing road conditions.
On road surfaces that have a loose
surface layer on a firm base with good
traction (on gravel, deep sand or snow,
for example), braking distances may be
longer than with locked wheels. This
also applies for driving with snow
chains. However, ABS continues to
provide enhanced vehicle stability and
steering response under these condi-
tions.

Page 105 of 187

BMW Z3 2002 User Guide 105n
IndexDataTechnologyRepairsMaintenanceControlsOverview
Winter operationThe onset of winter is often accompa-
nied by rapid changes in weather.
Adaptations in driving style should be
accompanied

105n
IndexDataTechnologyRepairsMaintenanceControlsOverview
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 vehicle
operation through the winter remains
safe and trouble-free.CoolantEnsure that the coolant contains the
year-round 50 : 50 ratio of water and
antifreeze with corrosion inhibitor. This
mixture provides protection against
freezing down to approx. Ð 34 7
(Ð 37 6). Replace the coolant every
three years.LocksBMW door lock deicer can be used to
free the doors if they are frozen. This
deicer also contains lubricant.
After using deicer, treatment with BMW
lock cylinder grease is recommended.
Rubber seals and components In order to prevent freezing, apply BMW
rubber treatment to weather-stripping
on the doors, hood, luggage compart-
ment and to convertible top seals.
A full range of car-care products is
available from your BMW center.< Snow chainsBMW snow chains
* can be mounted on
both summer and winter tires. Mount
them in pairs on the rear wheels only.
Comply with the manufacturer's safety
precautions. Do not exceed a speed
limit of 30 mph (50 km/h) when driving
with chains. As an exception in this
situation, we recommend that you
switch off the ASC+T/DSC
* system
when snow chains are mounted. Refer
to pages 73, 74.
Starting offWhen starting from a full stop or
"rocking" free in deep snow, we recom-
mend that you switch off the ASC+T/
DSC
* system, refer to pages 73, 74.
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. Shift down
into the next lowest gear when
approaching uphill or downhill grades.
Maintain an adequate distance between
yourself and the vehicle ahead.Brakes Winter road conditions substantially
reduce the traction available between
the tires and the road surface.
Remember that Ð in every situation Ð
braking distances will be significantly
longer as a result of this.
ABS is intended to prevent the wheels
from locking during brake applications,
thus helping to maintain vehicle stability
and steering response.

Page 106 of 187

BMW Z3 2002 User Guide 106n
Winter operation Power steeringIf it should occur that the ABS does not
respond in a critical braking situation
and the wheels lock: reduce the pres-
sure on the brake pedal until the wheels
j

Page 111 of 187

BMW Z3 2002 User Guide 111n
IndexDataTechnologyRepairsMaintenanceControlsOverview
Tire condition Tire replacementmoderate speeds and with only small
amounts of water on the road.
Never continue driving on a
deflated (flat

111n
IndexDataTechnologyRepairsMaintenanceControlsOverview
Tire condition Tire replacementmoderate speeds and with only small
amounts of water on the road.
Never continue driving on a
deflated (flat) tire. A flat tire greatly
impairs steering and braking response,
and can lead to complete loss of
control over the vehicle.
Avoid overloading the vehicle so that
the permitted load on the tires is not
exceeded. Overloading causes over-
heating and damage inside the tires.
The ultimate result can assume the
form of a sudden air loss.
Unusual vibrations encountered during
normal vehicle operation can indicate a
flat tire or some other vehicle malfunc-
tion. The type of problem can be
caused by contact with curbs, etc. This
is also true for irregularities in the
vehicle's handling characteristics, such
as a pronounced tendency to pull to the
left or right. Should this occur, respond
by immediately reducing your speed.
Proceed carefully to the nearest BMW
center or professional tire center, or
have the vehicle towed in to have it, its
wheels and tires inspected.
Tire damage (up to and including
sudden and complete air loss) can pose
an extreme hazard for both vehicle
occupants and other road users.< To maintain good handling and vehicle
response, use only tires of a single tread
configuration from a single manufac-
turer. BMW tests and approves wheel
and tire combinations, refer to page 116.
DOT Quality GradesTread wear
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.