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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
128n
Winter tiresChoosing the right tireBMW recommends winter tires (M+S
radial tires) for driving in adverse winter
road conditions. So-called all-season
tires with the M+S-identification mark
do indeed possess better winter trac-
tion than summer tires with the load
rating H, V, W, Y und ZR, but usually do
not achieve the same level of perfor-
mance as winter tires.
In the interests of safe tracking and
steering response, install radial tires
made by the same manufacturer and
with the same tread configuration on all
four wheels if you elect to mount winter
tires.
Mount only winter tires which have
been 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 pressureOnce the tire wears to below 0.16 in
(4 mm), winter tires display a percep-
tible decrease in their ability to cope
with winter driving conditions, and
should be replaced in the interest of
safety.
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.
StorageAlways 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 summer or winter tires is
approved only in pairs and only on the
rear wheels. Comply with all manufac-
turer's safety precautions when
mounting the chains.
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.
Comply with all manufacturer's safety
precautions when mounting the chains.
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IndexDataTechnologyRepairsCar careControlsOverview
Engine oilChecking the oil level 1 Park the vehicle on a level surface.
2 Shut the engine off after it has
reached normal operating tempera-
ture.
3 After approx. 5 minutes, pull the
dipstick out and wipe it off with a
clean lint-free cloth, paper towel, or
similar material.
4 Carefully push the dipstick all the way
into the guide tube and pull it out
again.
5 The oil level should be between the
two marks on the dipstick.
As with fuel economy, oil consumption
is directly influenced by your driving
style and vehicle operating conditions.462de244
The oil volume between the two marks
on the dipstick corresponds to approx.
1.1 US quarts (1 liter). Do not fill beyond
the upper mark on the dipstick. Excess
oil will damage the engine.460de189
To add oil Wait until the level has dropped to just
above the lower mark before adding oil.
However, never let the oil drop below
the lower mark.
BMW engines are designed to
operate without oil additives; the
use of additives could lead to damage
in some cases. This also applies to the
manual transmission, automatic trans-
mission, differential and power steering
system.<462de245
140n
The BMW Maintenance System has
been designed as a reliable means for
providing maximum driving and operat-
ing safety Ð and as cost effectively as
possible for you.
Please keep in mind that regular main-
tenance is not only necessary for the
safety of your vehicle, but also plays a
significant role in maintaining the resale
value of the vehicle.
Service Interval DisplayAdvanced technology is employed
to calculate the optimal maintenance
intervals. These are then indicated in
the Service Interval Display. While
conventional systems rely on distance
traveled alone to determine when
service is due, the BMW Maintenance
System has for years considered the 460us112
actual conditions under which the
vehicle operates, because miles can be
traveled in many different ways:
From a maintenance perspective,
62,000 miles (100,000 km) of short-
distance urban driving are not equiva-
lent to 62,000 miles (100,000 km)
covered at moderate speeds in long-
distance highway travel.
The BMW Maintenance System
includes the Engine Oil Service and
Inspections I and II.
Determining the maintenance intervals
according to the actual use of the vehi-
cle covers every kind of operating situa-
tion. However, even those who drive
only short distances Ð significantly less
than 6,000 miles (10,000 km) annually Ð
should have the engine oil changed at
least every 2 years since oil deterio-
rates over time, regardless of use.
Service and Warranty Information
Booklet (US models)/Warranty and
Service Guide (Canada models)For additional information on mainte-
nance intervals and procedures, please
refer to the Service and Warranty Infor-
mation Booklet (US models) or to the
Warranty and Service Guide (Canadian
models).
As a precaution against rust, it is
advisable to have the body checked for
damage from rocks or gravel at the
same time, depending upon operating
conditions.
Have your BMW center perform
maintenance and repair.
Your BMW center is always "up to date"
on the latest maintenance work and
repair techniques and equipped with
the required special tools. In addition,
checking parts known from experience
to be subject to wear is a permanent
part of the maintenance specifications.
Be sure that all maintenance work is
confirmed in the Service and Warranty
Information Booklet (US models) or the
Warranty and Service Guide (Canadian
models). These entries will constitute
your proof that the vehicle has received
regular maintenance. They are also
required for warranty claims.<
The BMW Maintenance System
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IndexDataTechnologyRepairsCar careControlsOverview
BatteryBattery careThe battery is completely maintenance-
free. That means that the original acid
will normally last for the service life of
the battery under temperate climatic
conditions.
For all questions that regard the
battery, please consult your BMW
center. Since the battery is absolutely
maintenance-free, the following is for
your information only.
please be cautious whenever you work
with or near the battery.
Before handling the battery,
please read the following infor-
mation.
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.
Do not allow children to have
access to batteries and battery
acid.
Never allow sparks or open
flame near the battery. Do
not smoke in the vicinity of the
battery. Avoid sparks from electrical
cables or electrical equipment. Turn the
key to position 0 in the steering lock
when disconnecting or connecting the
battery. Never short-circuit the battery
terminals. This creates a risk of injury
from high-energy sparks.
A highly explosive gas is gener-
ated when the battery is
charged.
If you happen to get acid in
your eyes, rinse thoroughly for
15 minutes with clear water.
Consult a physician immediately. If you
get acid spray on your skin or clothing,
rinse with plenty of water. If acid is
accidentally swallowed, consult a
physician immediately.
In order to protect the battery
case from ultraviolet radiation,
do not place it in direct sunlight.
A discharged battery can freeze. Store
the battery in areas where temperature
remains above freezing.
Removal and installation
Do not disconnect the battery
while the engine is running.
Disconnecting the battery cable when
the engine is running will cause a
voltage surge which will damage the
vehicle's onboard electronics.
Do not make any modifications in the
wires to the positive terminal. If you do
so, the protective function of the safety
battery terminal is no longer ensured.
Repairs and disposal may only be per-
formed by specially trained personnel.<
When removing the battery, disconnect
the cable on the negative terminal first,
then the cable on the positive terminal.
Loosen the center adjusting screw on
the battery retaining strap (use the
screwdriver included with the onboard
tool kit) and disconnect the strap.
When installing a battery, connect the
positive terminal first, then connect the
negative terminal.
When installing a battery, be sure
that it is mounted properly and that
the retaining strap is installed using the
center adjustment screw, otherwise, the
battery will not be secure enough in
case of an accident.<
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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
*
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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
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Self-diagnostics All of the important electrical and elec-
tronic systems in the vehicle are tested
regularly and automatically; the driver
does not have to perform any extra
operations or adjustments.
The indicator lamps also come on
briefly after the ignition has been turned
on.
While you are driving, the functional
status of the actuator motors (for the
windshield wipers, power windows,
seats, sliding/tilt sunroof, etc.) is
constantly analyzed by current
measurements in their relays.460de177
In the same manner, the electrical
resistance of the airbag ignition genera-
tors and all of the remaining airbag
components is measured at all times.
Any fault in this system would be
detected immediately by a current fluc-
tuation that would necessarily accom-
pany it. The fault would be indicated
immediately by the airbag warning
lamp.
Even after you shut off the engine, the
overall functional status of your vehicle
is monitored. For example, all of the
flaps of the heating and ventilation
system travel to the nearest limit posi-
tion. This action ensures that the
system will be able to provide
defrosting, regardless of other circum-
stances, e. g. if a malfunction in the air
conditioner/climate control system
should occur during the night while the
vehicle is parked.
A calibration cycle runs every tenth time
the engine is shut off. During this cycle,
the actuator motors move all air condi-
tioner/automatic climate control flaps to
their limit stops in both directions. The
limit positions and the return travel
paths are checked in this manner in
order to ensure that appropriate adjust-
ments for the operating elements can
be made at any time.You will hear the sounds of the air flaps
as the air conditioning system/auto-
matic climate control carry out their
self-diagnostic functions after the igni-
tion has been turned off. All of the other
self-diagnostics functions operate
silently in the background.
Any possible defects detected during
these self-diagnostics can be read out
by your BMW center and quickly
corrected during the vehicle's next
regularly scheduled maintenance.