2001 BMW 525I SPORT WAGON ABS

Index
Data
Technology
Repairs
Car care
Controls
Overview
143nAntilock Brake System (ABS)
The concept
ABS enhances active safety by helping
to prevent the wheels from locking un-
der braking. The reason: locked wheels
are dangerous, because the vehicle
cannot be steered when the front
wheels slip, and loss of traction at the
rear wheels can cause the rear end to
break into an uncontrolled skid.
ABS is designed to meet two essential
requirements during every brake appli-
cation:
>To help provide vehicle stability.
> To help retain steering and maneu-
vering capability on all types of road
surface (asphalt, concrete, dirt,
moisture, snow and ice).
With ABS, the shortest possible braking
distances are achieved under most
conditions (on straight-aways and in
curves, with different road surfaces).
Braking with ABS
The system becomes operative once
the vehicle exceeds a speed of approx.
6 mph (10 km/h). The ABS is deacti-
vated whenever the vehicle's speed
drops back below approx. 4 mph
(6 km/h). This means that the wheels
can lock in the final phase of a brake
application – a factor of no significance
in actual use.
The ABS system works best in situa-
tions requiring maximum pressure on
the pedal (full braking). Since the vehi-
cle maintains steering responsiveness,
you can nevertheless avoid possible
obstacles with a minimum of steering
effort.
The ABS closed-loop control circuit cy-
cles in fractions of a second. A pulsing
of the brake pedal, combined 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 your
vehicle's speed to road conditions. On road surfaces which have a loose
layer on a firm base (on gravel or snow,
for instance), the braking distances with
ABS may be longer than with the
wheels locked. This also applies to
driving with snow chains. However,
ABS continues to provide enhanced
vehicle stability and steering response
under these conditions.

144nAntilock Brake System (ABS) Disc brakes
Information for your safety
Not even ABS can suspend the laws of
physics. The consequences of brake
applications with inadequate safety
clearances between vehicles, exces-
sive speed or if aquaplaning occurs are
always the responsibility of the driver.
You should never allow the added
safety margin of ABS to mislead you
into taking risks of any kind.
Do not make any modifications to
the ABS system.
Service procedures on ABS are to be
performed by authorized technicians
only. <
In the event of a fault
The ABS warning lamp in the in-
strument cluster comes on, refer
to page 23. The brake system
then reverts to conventional op-
eration as on vehicles without
ABS. However, have the brake
system checked by your BMW center
as soon as possible. To prevent unde-
tected defects and cumulative faults
from adversely affecting the brake sys-
tem, refer any problems to your BMW
center at the earliest opportunity.
Disc brakes furnish optimum decelera-
tion and braking control and greater
fade resistance under heavy use.
When the vehicle is driven only occa-
sionally, during extended periods when
the vehicle is not used at all, and in
operating conditions where brake appli-
cations are less frequent, there is an
increased tendency for corrosion of the
rotors and accumulation of contamina-
tion on the brake pads. This occurs
because the minimal pressure which
must be exerted by the pads during
brake applications to clean the rotors is
not reached.
If the brake rotors are corroded, they
will tend to respond to braking with a
pulsating effect which even extended
application will fail to cure.
For your own safety: use only
brake pads that BMW has
approved for your specific vehicle
model. BMW cannot evaluate non-
approved brake pads to determine if
they are suited for use, and therefore
cannot ensure the operating safety of
the vehicle if they are installed. <

Index
Data
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Repairs
Car care
Controls
Overview
145nDisc brakes
Driving notes
When driving in wet conditions and in
heavy rain, it is effective to apply light
pressure to the brake pedal every few
miles (kilometers). Watch traffic condi-
tions to ensure that this maneuver does
not endanger other road users. The
heat which is generated by the brake
applications helps to dry the brake
pads and rotors.
Maximum braking force is obtained
while the wheels continue to rotate,
peaking when the wheels remain on the
verge of locking without actually doing
so. ABS maintains this state automati-
cally. If the ABS fails, you should revert
to the staggered braking technique
described below (refer to page 147).
Extended or steep mountain descents
should be driven in the gear in which
only minimal periodic brake applica-
tions is required. This avoids excessive
strain on the brakes and possible im-
pairment of the braking effect.
The braking effect of the engine can be
further increased by downshifting, into
first gear, if necessary. In the manual
mode of the automatic transmission,
you can also downshift into first gear.
Refer to page 76. Should engine braking prove inade-
quate, you should still avoid extended,
continuous braking. Instead of main-
taining low to moderate pressure over
an extended period of time, you should
decelerate by applying more substantial
pressure to the brake pedal (watch for
following traffic!), then releasing the
pedal, then repeating the application.
This staggered braking technique
allows the brakes to cool in the intervals
between active braking phases,
preventing overheating and ensuring
that full braking capacity remains avail-
able at all times.
Do not coast with the clutch de-
pressed or with the transmission
or selector lever in Neutral. Do not
coast with the engine shut off. The
engine provides no braking effect when
the clutch is depressed or the transmis-
sion is in neutral, and there is no
power-assist for braking or steering
when the engine is not running.
Never allow floor mats, carpets or any
other objects to protrude into the area
around the accelerator, clutch and
brake pedals and obstruct their move-
ment. <
Dynamic Brake Control (DBC)*
If you apply the brakes rapidly, this
system automatically produces the
maximum braking force boost and thus
helps to achieve the shortest possible
braking distance during "panic stops."
All of the benefits of the ABS system
are exploited under these circum-
stances.
Do not reduce the pressure on the
brake pedal for the duration of the
brake application. When the brake
pedal is released, the DBC is deacti-
vated.
In the event of a malfunction, the yellow
warning lamp comes on. Conventional
braking efficiency is available without
limitations.
Have the system checked and repaired
at your BMW center as soon as possi-
ble.
For "Information for your safety"
covering the ABS system, refer to
page 144. This information also gener-
ally applies for DBC. <

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Overview
147nWinter operation
Rubber seals and components
In order to prevent the weather-strip-
ping from freezing, apply BMW rubber
treatment or silicone spray to the seals
on the doors, hood and luggage com-
partment lid/tailgate.
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).
For maximum traction, we recommend
that you manually deactivate the
ASC+T/DSC
* when driving with snow
chains mounted. Refer to page 102.
Starting off
We recommend that you use the
manual control switch to deactivate
ASC+T/ DSC
* when starting off in deep
snow or when rocking the car to free it
(refer to page 102).
Driving on low-traction road
surfaces
Use smooth, gentle pressure to control
the accelerator pedal. Avoid excessive
engine speeds and shift to the next
higher gear at an early point. Adapt
your speed and driving style when ap-
proaching grades or slopes. Maintain
an adequate distance between yourself
and the vehicle ahead.
Brakes
Winter road conditions substantially
reduce the amount of traction available
between the tires and the road surface.
The resulting increases in braking dis-
tance are considerable and should be
kept in mind at all times.
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.
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. 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 which
provide only poor or uneven traction. <

Index
Data
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Repairs
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Controls
Overview
153nTire rotation Wheel and tire combinations
Should you decide to rotate the tires, it
is essential to comply with the follow-
ing: rotate tires on the same side only,
since braking characteristics and road
grip could otherwise be adversely
affected.
Following tire rotation, correct the tire
inflation pressure.
If different tire sizes are mounted
on the front and rear axles (refer to
page 156), the wheels may not be
rotated from one axle to the other. Use only tires approved by BMW.
Refer to the information beginning on
page 156.
Because of the high speeds this vehicle
can reach, the use of specific tire
brands, specifications and dimensions
is mandatory. Consult any BMW center
for details.
Comply with national, state, or province
regulations.
The correct wheel-tire combina-
tion affects different systems such
as ABS, ATC, ASC+T/DSC. The func-
tion of these systems is impaired if im-
proper wheel-tire combinations are
used.
For this reason, use only tires of the
same brand and tread pattern. In the
event of a flat tire if you have mounted
winter tires, for example, remount the
approved wheel-tire combination as
soon as possible. <
Codes on tires and wheels
The tire codes will aid you in selecting
the correct tire.
Codes on radial tires:
The speed rating indicates the ap-
proved maximum speed for the tire.
Summer tires:
S = up to 112 mph (180 km/h)
T = up to 118 mph (190 km/h)
H = up to 130 mph (210 km/h)
V = up to 150 mph (240 km/h)
W = up to 167 mph (270 km/h)
Y = up to 186 mph (300 km/h)
ZR= over 150 mph (240 km/h)Example:
Nominal width
in mm
Aspect ratio in %
Radial tire code
Rim diameter in inches
Load rating
(not on ZR tires)
Speed rating
(before R on ZR tires)
235/60 R 16 100 W

168nCoolant Brake fluid
Adding coolant
Wait until the engine cools before
removing the cap from the expansion
tank. The needle of the coolant temper-
ature gauge in the instrument cluster
must be located in the blue zone; other-
wise, there is a danger of scalding.
1 Start by turning the cap counter-
clockwise. Pause to allow any
accumulated pressure to escape,
then open.
2 If the coolant is low, slowly add coolant until the correct level is
reached – do not overfill.
The coolant is a mixture of water and
extended-duty antifreeze with corrosion
inhibitor. Always maintain the pre-
scribed all-season 50:50 mixture ratio
for year-round protection against inter-
nal corrosion. No other additives are re-
quired.
Replace the coolant every four years.
If the indicator lamp for the
brake hydraulic system comes
on or if the "CHECK BRAKE
FLUID" warning appears in the
Check Control
*: the brake fluid
level is too low in the reservoir.
The brake fluid reservoir is located
under the microfilter housing on the
driver's side of the car. Should you de-
termine that the brake fluid is low, refer
the problem to your BMW center, who
can trace and rectify any sources of
leakage when refilling the reservoir.
Your BMW center is familiar with the
specifications for approved brake
fluids (DOT 4).
Brake fluid loss results in extended
pedal travel. For this situation, refer to
the notes on page 146.
Brake fluid is hygroscopic, that is,
it absorbs moisture from the air
over time.
In order to ensure the safety and
reliability of the brake system, have
the brake fluid changed every two years
by an BMW center. Refer also to the
Service and Warranty Information
Booklet (US models) or to the Warranty
and Service Guide Booklet (Canadian
models).
Brake fluid is toxic and damages the
vehicle's paint. You should always store
it in its original container and in a loca-
tion which is out of reach of children.
Do not spill the fluid and do not fill the
brake fluid reservoir beyond the "MAX"
mark. The brake fluid could ignite upon
contact with hot engine parts and
cause serious burns. <
Comply with the applicable
environmental laws regulating the
disposal of brake fluid. <

Index
Data
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Repairs
Car care
Controls
Overview
193nChanging a wheel Battery
When storing the wheel, take care to
ensure that you do not damage the
retaining pin in the spare tire recess.
If light-alloy wheels other than original
BMW light-alloy wheels have been
mounted, it may be necessary to use
different lug bolts for those wheels.
Replace the defective tire as soon as
possible and have the new wheel/tire
balanced.
Size 255/40 R17 94 W
* tires on
the rear axle:
In the event of a puncture or other tire
failure, it may be necessary to mount
the spare tire of different size at the
rear. This tire is of full capacity in all
load and speed ranges. Nevertheless,
mount a tire of the correct size as soon
as possible. <
Battery posts, terminals, and re-
lated accessories contain lead
and lead compounds. Wash hands after
handling. <
Installation location
The battery is located behind the right-
hand side trim panel in the luggage
compartment.
Fold the trim panel down with the
handle at the top. On the sport wagon,
press the button.
If a subwoofer
* is installed on the sport
wagon, loosen the T-screw and swing
the subwoofer to the side.
390de610
Maintenance
The battery is absolutely maintenance-
free, that is, the original electrolyte will
normally last for the service life of the
battery under moderate climatic condi-
tions.
Symbols
You will find the following symbols on
your vehicle battery. To avoid injury,
please comply with the corresponding
precautions whenever you work with or
near the battery.
Please read the following infor-
mation before working with the
battery.
Wear eye protection. Do not al-
low particles containing battery
acid or lead to come into con-
tact with your eyes, your skin, or your
clothing.
Battery acid is extremely corro-
sive. Wear eye protection and
protective gloves. Do not tip the
battery. Battery acid can leak from the
ventilation openings.
Be sure that children keep well
away from batteries and battery
acid.

202nTowing the vehicle
The towed vehicle should always
be the lighter of the two vehicles.
If this is not the case, it is no longer
possible to control vehicle response. <
Tow-starting
It is not possible to start the engine of
vehicles equipped with an automatic
transmission by towing or pushing.
For instructions on jump starting, refer
to page 200.
Never attempt to use your vehicle to
push another vehicle, since damage to
the energy-absorbing bumpers could
result.
Towing a vehicle with automatic
transmission
1 Place the selector lever in position N.
2 Towing speed: Max. 45 mph (70 km/h).
3 Towing distance: Max. 95 miles (150 km).
4 Leave the ignition key in position 1 to ensure that the brake lamps, turn sig-
nals, horn and windshield wipers re-
main operative, and to prevent the
steering lock detent from engaging.
5 Switch on the hazard warning flash- ers (observe country-specific regula-
tions).
Find some means of identifying the ve-
hicle in tow, for instance, place a sign
or warning triangle in the rear window.
Make sure that the ignition key
remains in position 1 even when
the electrical system has failed to pre-
vent the steering lock from engaging.
The steering and brakes are without
power assist when the engine is off.
This means that increased effort is
required for steering and braking. <
Towing with a commercial
tow truck
> Do not tow with sling-type equip-
ment.
> Use a wheel lift or flat bed carrier.
> Please comply with applicable towing
laws.
Never allow passengers to ride in
a towed vehicle for any reason. <
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