86
Dynamic Stability Control (DSC)The conceptDSC maintains vehicle stability, even in
critical driving situations.
DSC is operational every time you start
the engine.
DSC incorporates the Dynamic Traction
Control (DTC) and Cornering Brake
Control (CBC) functions.
For information on vehicles with all-
wheel drive, refer to page 88 ff.Indicator lamps
The indicator lamp in the instru-
ment cluster goes out shortly
after you switch on the ignition,
refer to page 19.
>The indicator lamp flashes: DSC con-
trols the drive and braking forces
>The indicator lamp stays lit: DSC has
been switched off with the button;
DTC and DBC are operational. DTC
control intervention is not indicated.
The indicator lamp and the
brake warning lamp continu-
ously light up in yellow:
The DSC, DTC and DBC have
been switched off manually or
there is a system malfunction.
The vehicle will remain completely
operational, however, without DSC. In
the event of a fault, please consult your
BMW center.
Indicator and warning lamp for
Canadian models.
Deactivating the DSC/activating
the DTCPress the DSC button briefly, the indi-
cator lamp comes on and remains lit.
DSC is deactivated; DTC is operational.
In the following rare situations, it may
prove useful to activate the DTC for a
brief period:
>When rocking the vehicle or starting
off in deep snow or on loose surfaces
>When driving on snow-covered
grades, in deep snow, or on a snow-
covered surface that has been
packed down from being driven on
>When driving with snow chains.
Traction is increased by deactivating
the control systems that enhance trac-
tion under normal conditions.
90
Hill Descent Control (HDC)*The conceptBy reducing the vehicle's speed on
steep downhill stretches, HDC main-
tains predictable vehicle handling
response to provide you with control of
your BMW during extreme descents.
The vehicle slows to a pace just slightly
faster than walking speed.
HDC is available for activation at vehi-
cle speeds below approx. 22 mph /
35 km/h. When driving down steep
hills, the vehicle reduces speed auto-
matically down to about double walking
speed – approx. 7.5 mph / 12 km/h –
and then maintains this speed at a con-
stant.
You can use the accelerator or brakes
to vary this speed within a range from
approx. 3 mph / 5 km/h to approx.
15 mph / 25 km/h.
In conjunction with the multifunction
steering wheel you can use the +/–
button to set the cruise control to a tar-
get speed in the range from approx.
3 mph / 5 km/h to approx. 15 mph /
25 km/h.
HDC is automatically deactivated once
vehicle speed again exceeds approx.
37 mph / 60 km/h.
To activate the systemPress the HDC button; the green indi-
cator lamp integrated within the button
comes on.
The indicator lamp flashes whenever
the system is actively intervening to
control your speed with automatic
brake applications.To deactivate the systemPress the button again, the indicator
lamp goes out.
HDC is automatically deactivated once
the vehicle accelerates to more than
37 mph / 60 km/h, as well as whenever
you switch off the ignition.
To use HDCWith manual transmission:
You should always ensure that either
reverse or first gear is engaged before
using HDC, as the engine's braking
effect is most pronounced in these
gears, and only reduced engine braking
is available in higher gears.
With automatic transmission: HDC is
available for use in all ranges.System malfunctionsSignaled by the indicator lamp, which
responds to problems by going out
while HDC is in operation or by failing
to come on when you activate the sys-
tem:
HDC is temporarily not available if
brake temperature is too high.
If the DSC indicator lamp comes
on at the same time:
There is a fault in the HDC and
DSC systems. Have your BMW center
inspect this system as soon as possi-
ble.
91
Flat Tire Monitor*The conceptAs you drive, the Flat Tire Monitor
keeps track of pressure levels in all four
tires. The system alerts you whenever
the inflation pressure of a tire falls sig-
nificantly below the pressure of another
tire.
The system actually detects pressure
loss by monitoring differences in the
relative speeds of the four wheels. It
interprets variations outside specified
limits as severe pressure loss, and then
responds by generating a warning.Functional requirementsIn order for the Flat Tire Monitor to learn
the correct tire inflation pressure,
please do the following:
1. Check the tire inflation pressures in
all tires
2. Compare them with the tire inflation
pressure table on page 26 and cor-
rect them, if necessary
3. Initialize the system.
System limitations
The Flat Tire Monitor cannot pro-
vide you with advance warning of
sudden and severe tire damage caused
by external factors and does not detect
the balanced and very gradual pressure
loss that takes place in all four tires
over an extended period of time.<
On the other hand, the following situa-
tions can lead to a delayed detection of
pressure loss and even to the system
not functioning:
>Driving on snow-covered or slippery
roads
>Performance-oriented driving: slip at
the drive wheels, high levels of lateral
acceleration
>When driving with snow chains, false
warnings and undetected pressure
losses may occur
>When driving with a space-saver
spare tire, the Flat Tire Monitor can-
not function.
Initializing the system
Each time you correct the pres-
sure in a tire, or change a wheel or
tire, reinitialize the system immediately
afterwards. This requires a bit of driv-
ing.<
1. Before driving off, start the engine
but do not start driving
2. Press the button as long as you need
to until the yellow indicator lamp in
the instrument cluster lights up for a
few seconds
3. Drive off.
It takes a few minutes before the Flat
Tire Monitor can detect a flat tire and
issue a warning.
OverviewControlsMaintenanceRepairsDataIndex
92
When driving with snow chains or
a space-saver spare tire, do not
initialize the system.<
Flat tire
The indicator lamp in the instru-
ment cluster lights up red. This
visual alert is accompanied by
an acoustic warning signal.
1. Carefully reduce speed and come to
a stop. Avoid sudden braking and
steering maneuvers
2. Determine which wheel is damaged
If this cannot be determined, con-
tact your BMW center.<
3. Replace the damaged wheel, refer to
Changing a wheel on page 147.
After replacing the damaged tire, initial-
ize the system.
Vehicles with Run Flat tires:
1. Carefully reduce your speed to under
50 mph / 80 km/h. Avoid strong
braking and steering maneuvers. Do
not exceed a speed of 50 mph /
80 km/h.
Because the sides of Run Flat
tires are reinforced, a drop in infla-
tion pressure usually cannot be
detected from the outside, refer to Run
Flat tires, page 150.<
2. To continue driving, follow the
instructions under Driving with a
damaged tire on page 151.
System malfunction
The indicator lamp in the instru-
ment cluster lights up yellow.
The Flat Tire Monitor is malfunc-
tioning or out of order. Please refer the
problem to your BMW center.
Brake force displayThe brake force display indicates to the
driver of the vehicle behind you how
hard you are braking your vehicle.
The display has two levels:
>Normal braking: the brake lamps
among the rear lamps and the center
brake lamp light up
>Hard braking or use of ABS: the tail
lamps light up with the same bright-
ness as the brake lamps and thereby
intensify the visual effect of the brake
lamps.
Flat Tire Monitor*
121
General driving notes
Brakes: do not rest your foot on
the brake pedal while driving.
Even light but consistent pedal pres-
sure can lead to high temperatures,
brake wear and possibly even brake
failure.
Hydroplaning: when driving on wet or
slushy roads, reduce road speed. If you
do not, a wedge of water can form
between tires and road surface. This
phenomenon can lead to partial or
complete loss of contact between the
tires and road surface, as well as loss of
vehicle control and braking ability.
Driving through water: do not drive
through water on the road if it is deeper
than 1 ft/30 cm, and then only at walk-
ing speed. Otherwise, the vehicle's
engine, the electrical systems and the
transmission may be damaged.
Cargo area cover: never use it to store
heavy or hard objects; otherwise, occu-
pants could be injured if the vehicle is
braked hard.
Clothes hooks: when hanging clothing
from the hooks, be sure that they will
not obstruct the driver's vision. Do not
hang heavy objects on the hooks. If you
do so, they could cause personal injury
during braking or evasive maneuvers.<
Antilock Brake System (ABS)The conceptABS keeps the wheels from locking
during braking, thereby enhancing
active driving safety.Braking with ABSIf you are in a situation that requires full
braking, you will exploit the full benefits
of ABS system if you apply maximum
pedal pressure – panic stop. Since the
vehicle maintains steering responsive-
ness, you can avoid possible obstacles
with a minimum of steering effort,
despite the full brake application.
Pulsation at the brake pedal combined
with sounds from the hydraulic circuits
indicates to the driver that ABS is in its
active mode.Dynamic Brake Control (DBC)DBC is included in the DSC, refer to
page 86.
The system responds to sudden, high-
intensity applications of force to the
brake pedal by automatically braking
the vehicle with maximum boost to
achieve the shortest possible braking
distances during panic stops. This sys-
tem exploits all the benefits of ABS.Do not reduce the pressure exerted
against the brake pedal until the brak-
ing maneuver has been completed.
DBC is deactivated when you release
the brake pedal.
Cornering Brake Control (CBC)CBC is an advanced engineering
design of the ABS. When braking while
cornering at high speed or braking dur-
ing high lateral acceleration, or when
braking during a lane change, vehicle
stability is improved and steering
response is enhanced.
OverviewControlsMaintenanceRepairsDataIndex
122
Brake systemBrake fluid levelLow brake fluid level in the reservoir
combined with longer than usual pedal
travel may indicate a defect in one of
the brake system's hydraulic circuits.
Proceed to the nearest BMW cen-
ter. It may be necessary to apply
higher levels of pressure to the pedal
when stopping and braking distances
may also be longer. Please remember
to adapt your driving style accord-
ingly.
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 that must
be exerted by the pads to clean the
rotors by brake applications is not
reached.
Corrosion on brake rotors is signaled by
a running or pulsation during braking;
even extended subsequent braking will
not cure this phenomenon.
It is a good idea to periodically dry the
brakes with a gentle application when
driving in rain and on wet roads. Watch
traffic conditions to ensure that this
maneuver does not endanger other
road users. The heat generated in this
process helps dry the pads and rotors
to ensure that your brake system will
respond with undiminished efficiency
when you need it.
When descending steep hills and
extended grades, downshift to a gear
that will allow you to continue safely
with only a minimal amount of braking.
This helps avoid placing excessive
loads on the brake system. Use care to
avoid exceeding the approved engine-
speed range, refer to page 79.Do not coast with the clutch
depressed or with the transmis-
sion or selector lever in Neutral. Do not
coast with the engine shut off. The
engine provides no braking effect when
the clutch is depressed and there is no
power-assist for braking or steering
when the engine is not running.
325xi: always refer all brake inspection
and service work to your BMW center,
as failure to observe the special proce-
dures could result in damage to com-
ponents of the all-wheel drive.
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.<
Brake pads
For your own safety: use only
brake pads which BMW has
approved for your specific vehicle
model. BMW cannot evaluate non-
approved brake pads to determine if
they are suitable for use, and therefore
cannot ensure the operating safety of
the vehicle if they are installed.<
124Wheels and tires
Tire inflation pressureInformation for your safetyThe factory-approved tires are matched
to your vehicle and have been selected
to provide optimum safety and driving
comfort when used properly.
It is not merely the tire's service life, but
also driving comfort and – above all else
– driving safety that depend on the con-
dition of the tires and the maintenance
of the specified tire inflation pressure.
Incorrect tire inflation pressure is a fre-
quent cause of tire damage. It also sig-
nificantly influences the roadholding
ability of your BMW.
Be sure to check the tire inflation
pressure, including the space-
saver spare tire or the spare tire, on a
regular basis, at least twice a month
and before every extended journey,
refer to page 25. If this is not done,
incorrect tire pressures can cause driv-
ing instability and tire damage, ulti-
mately resulting in accidents.<
Tire conditionTire tread – tire damageInspect your tires frequently for tread
wear, signs of damage and for foreign
objects lodged in the tread. Check the
tread depth.
Tread depth should not be allowed to
go below 1/8 in / 3 mm, even though
the legally specified minimum tread
depth is 1/16 in / 1.6 mm.
Below 1/8 in / 3 mm tread depth, there
is a great risk of hydroplaning, even at
relatively moderate speeds and with
only small amounts of water on the
road. Tread wear indicators – see arrow
– are embedded in the base of the tire's
tread. Their locations are indicated by
the letters TWI – Tread Wear Indicator –
at various points on the tire's shoulder.
When the tread reaches a depth of
1/16 in / 1.6 mm, these indicators
appear and signal that the tires have
worn to the minimum legal level.
125
Do not drive on a deflated – flat –
tire unless your vehicle is
equipped with Run Flat tires. 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 can lead to
overheating and internal tire damage.
The ultimate result can assume the
form of a sudden air loss.
Unusual vibrations encountered during
normal vehicle operation can indicate a
damaged tire or some other vehicle
malfunction. This 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 or its tires inspected.
Tire damage, up to and including sud-
den and complete air loss, can endan-
ger the lives of both the vehicle occu-
pants and other road users.<
Tire replacementTo maintain good handling and vehicle
response, use only tires of a single
tread configuration from a single manu-
facturer.
Comply with the specified tire inflation
pressures — and be sure to have the
wheel and tire assembly balanced
every time you change a tire or wheel.DOT quality gradesTread wear
Traction AA A B C
Temperature A B C
All passenger car tires must con-
form to Federal Safety Require-
ments in addition to these grades.
when tested under controlled condi-
tions on a specified government test
course.
For example, a tire graded 150 would
wear one and one-half – 1
1/2 – 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.
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.
Tire condition
OverviewControlsMaintenanceRepairsDataIndex