2004 BMW 645CI COUPE&CONVERTIBLE brake

Technology for comfort, convenience and safety
76 indicate the presence of objects in green
before they are close enough to generate a
signal tone.
Control Center, for principle details, refer to
page 16:
1.Press button.
The start menu is opened
2.Press the controller to open the menu
3.Select "Vehicle settings" and press the
controller
4.Select "PDC" and press the controller
5.Select "Monitor display on" and press
the controller.
The PDC screen is activated.
The display appears on the Control Display
as soon as PDC is activated.
Depending on which key you have used to
open the vehicle, the last adjustment is
applied.
System limits
Even with PDC, final responsibility for
estimating the distance between the
vehicle and any obstructions always
remains with the driver. Even when sensors
are involved, there is a blind spot in which objects cannot be detected. The system is
also subject to the physical limits that apply
to all forms of ultrasonic measurement,
such as those encountered with thin and
wedge-shaped objects, etc. Low objects
already displayed, e.g. a curb, can also dis-
appear from the detection area of the sen-
sors again before a continuous tone
sounds.
Loud noises from outside and inside your
vehicle may prevent you from hearing the
PDC signal tone.<
Do not apply high pressure spray to
the sensors for a prolonged period of
time. Keep the spray at least 4 in/10 cm
away from the sensors.<
Driving stability control
systems
Your BMW is equipped with an extended
array of systems designed to enhance and
maintain vehicle stability under extreme
conditions. The following section describes
these functions based on ABS and DSC.
ABS Antilock Brake System
ABS enhances active safety by preventing
the wheels from locking under braking.
ABS is operational every time you start the
engine. ABS includes the functions CBC
Cornering Brake Control and EBV Elec-
tronic brake-force distribution.
CBC Cornering Brake Control
It provides further enhancements in vehicle
stability and steering response during lane
changes and cornering at high rates of lat-
eral acceleration.
EBV Electronic brake-force
distribution
EBV controls the brake system's applica-
tion pressure at the rear wheels to ensure
stable deceleration.

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DSC Dynamic Stability Control
DSC optimizes vehicle stability during
acceleration and when starting from a full
stop, as well as optimizing traction. The
system recognizes any tendency for the
vehicle to assume an unstable attitude
such as oversteer or understeer; it then
counteracts this tendency with a combina-
tion of graduated reductions in engine
torque and selective braking intervention at
individual wheels. DSC provides optimal
stability within the limits defined by the
laws of physics.
The DSC is operational every time you start
the engine. DSC includes the functionality
of the DTC Dynamic Traction Control and
DBC Dynamic Brake Control, see below.
Indicator lamp
The indicator lamp goes out soon
after you start the engine.
The indicator lamp flashes:
DSC controls the drive and braking forces.
The indicator lamp stays lit:
DSC has been switched off via the button.
DTC Dynamic Traction Control
In special driving states, e.g. in deep snow,
DTC ensures maximum forward momen-
tum. The gain in forward momentum also
involves a reduction in driving stability.
DTC is active up to approx. 45 mph/
70 km/h, whereas DSC is only effective to
a limited degree.
You may find it useful to briefly activate
DTC under the following special circum-
stances:
>When rocking the vehicle and starting
off in deep snow or on loose road sur-
faces
>When ascending snow-covered hills,
and when driving in deep or on hard-
packed snow
>When driving with snow chains.
Activating DTC
>Press the DSC button briefly; the DTC
indicator lamp in the instrument cluster
lights up continuously.
Deactivating DTC again
Press the DSC button briefly again; the
DTC indicator lamp in the instrument clus-
ter goes out.
Switching off DSC
Press the DSC button until the DSC indica-
tor light in the instrument cluster lights up
continuously, however not longer than
approx. 10 seconds. DSC and DTC are
deactivated. In addition, the stability pro-
moting intervention of the active steering is
deactivated, refer to page 80.
A message appears on the Control Display.
Please note any supplementary information
that appears there.
To maintain optimal stability, drive
with the system on whenever possi-
ble.<
Reactivating DSC
Press the DSC button briefly; the indicator
lamp in the instrument cluster goes out.

Technology for comfort, convenience and safety
78 The laws of physics cannot be
repealed, even with DSC. An appro-
priate driving style always remains the
responsibility of the driver. Therefore, do
not reduce the additional safety margin
again by taking risks.<
DBC Dynamic Brake Control
When you apply the brakes rapidly, this
system automatically produces the maxi-
mum braking force boost and thus helps to
achieve the shortest braking distance dur-
ing panic stops. This system exploits all of
the benefits provided by ABS.
Do not reduce the pressure on the brake
pedal for the duration of the brake applica-
tion. When the brake pedal is released,
DBC is deactivated.
Malfunctions of driving stability
control systems
The brake system warning lamp
lights up in red, appearing together
with the indicator lamps for ABS
and DSC. A message appears on
the Control Display. Driving stability
control and ABS have failed. Con-
ventional braking efficiency remains
available without limitations.
While you may continue, you should
remember to proceed cautiously and drive
defensively while avoiding full brake appli-
cations.
Have the system checked as soon as pos-
sible.
Display of the previously described
malfunction on Canadian models.
The DSC warning lamp lights up.
DSC and DTC have failed.
The stability maintenance functions
are no longer available. The vehicle will
remain completely operational, however,
without DSC.Have the system checked as soon as pos-
sible.
The warning lamp for the brake sys-
tem lights up yellow and a message
appears on the Control Display.
DBC has failed.
Have the system checked as soon as pos-
sible.
Display of the previously described
malfunction on Canadian models.
Active roll stabilization*
The concept
Active roll stabilization minimizes body roll
and optimizes vehicle stability during cor-
nering and evasive maneuvers.
Dynamic stabilizers at the front and rear
axles form the basis for active roll stabiliza-
tion. Suspension compliance adapts to suit
driving conditions, varying from perfor-
mance-oriented during cornering to
smooth and comfort-oriented when the
vehicle is proceeding in a straight line. Dur-
ing vehicle operation, the system continu-
ously runs through closed-loop control
cycles lasting only fractions of a second.
The system assumes operational status
each time you start the engine.
Malfunction
The warning lamp lights up and a
message appears on the Control
Display. There is a malfunction in
the system. Have the system checked as
soon as possible.
If there is a malfunction in the system,
please remember to adapt your
speed accordingly, especially in curves.
The suspension will be noticeably softer
and the vehicle will display a greater ten-
dency to tilt during cornering and in cross-
winds.
If a message stating that you should stop
appears on the Control Display, stop and
switch off the engine as soon as possible.
In this case the oil level in the reservoir may

Technology for comfort, convenience and safety
80
Report of a flat tire
The warning lamp lights up in red
and a message appears on the
Control Display. In addition, an
acoustic signal sounds. There is a flat tire
or extensive inflation pressure loss.
1.Cautiously reduce the vehicle speed to
below 50 mph/80 km/h. Avoid sudden
braking and steering maneuvers. Do
not exceed a vehicle speed of 50 mph/
80 km/h
Due to the reinforcement on the
side walls of the run-flat tires,
inflation pressure loss can not usually
be recognized from the outside, refer to
Run-flat tires on page 168.<
2.To continue driving, comply with the
instructions for driving with damaged
tires on page 168.
Malfunction
The warning lamp lights up yellow
and a message appears on the
Control Display. The Flat Tire Moni-
tor has a malfunction or has failed. Have
the system checked as soon as possible.
Active steering*
The concept
The active steering is a system that actively
varies the steering angle of the front wheels
in relation to the steering wheel move-
ments.
When you are driving in the low road speed
range, e.g. in a town or when parking, the
steering angle of the wheels is reinforced,
i.e. the steering becomes very direct.
In the higher speed range, on the other
hand, the steering angle of the wheels is
reduced more and more. This improves the
handling capability of your BMW over the
entire speed range.
In critical situations, the system can make
targeted changes to the steering angle pro-
vided by the driver and thus stabilize the
vehicle before the driver intervenes.
Malfunction
The fixed warning lamp lights up.
The active steering is no longer
operational. In the low speed range,
greater steering wheel movement is neces-
sary. Have the system checked.
If the warning lamp lights up during the first
engine starting following a power supply
interruption, the system must be activated
with initialization.
Initializing system
1.Start the engine
2.With the vehicle stationary, turn the
steering wheel from the straight-ahead
position to the left as far as it will go and
then back to the straight-ahead position
3.Switch off the engine.
When you start the engine again, all the
functions of the active steering are avail-
able once again.
Brake Force Display
The two-stage brake lamps light up in two
stages depending on how strongly you
brake.
>Normal braking:
The brake lamps and the third brake
lamp go on
>Heavy braking and braking with ABS:
In addition, the light area of the rear
brake lamps is enlarged, refer to illus-
tration.

Things to remember when driving
102
Things to remember when driving
Break-in procedures
To ensure that your vehicle continues to
provide optimized economy of operation
throughout an extended service life, we
request that you devote careful attention to
the following section.
Engine and differential
Up to 1,200 miles/2,000 km:
You should attempt to vary both vehicle
and engine speeds. Until the break-in
period has been completed, you should
also refrain from exceeding an engine
speed of 4500 rpm or a driving speed of
100 mph/160 km/h.
Always obey all official speed limits.
Avoid full-throttle operation and use of the
transmission's kickdown mode during
these initial miles.
Once you have driven 1,200 miles/
2,000 km, the engine and vehicle speeds
can be gradually increased.
SMG Sequential manual
transmission
Do not use the acceleration assistant dur-
ing the break-in period, refer to page 60.
Tires
Due to technical factors associated with
their manufacture, tires do not achieve their
full traction potential until after an initial
break-in period. Therefore, drive reservedly
during the first 200 miles/300 km.
Brake system
Brakes require an initial break-in period of
approx. 300 miles/500 km to achieve opti-
mized contact and wear patterns between
brake pads and rotors.
Clutch
The function of the clutch is only at its opti-
mized level after a distance driven of
approx. 300 miles/500 km. During this
break-in period, engage the clutch gently.
After component replacement
You should also comply with these break-in
procedures should the components men-
tioned above need to be replaced at a later
point.
General driving notes
Hot exhaust system
Extreme temperatures occur at the
catalytic converter on this and every
catalyst-equipped vehicle. Do not remove
the heat shields installed adjacent to vari-
ous sections of the exhaust system, and
never apply undercoating to them. When
driving, standing at idle and while parking,
take care to avoid possible contact
between the hot exhaust system and any
highly flammable materials such as hay,
leaves, grass, etc. Such contact could lead
to a fire, and with it the risk of serious prop-
erty damage as well as personal injury.<
Parking vehicle
Condensation forms in the air conditioner
system during operation, and then exits
under the vehicle. Traces of condensed
water under the vehicle are thus normal.
Before driving into a car wash
Fold in the exterior mirrors manually, as
otherwise they could be damaged due to
the width of the vehicle.
Hydroplaning
When driving on wet or slushy roads,
reduce road speed. If you do not, a
wedge of water can form between tires and

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road surface. This phenomenon is referred
to as hydroplaning, and is characterized
by a partial or complete loss of contact
between the tires and the road surface, ulti-
mately undermining your ability to steer
and brake the vehicle.<
The risk of hydroplaning increases as the
tread depth of the tires decreases, also
refer to Tire tread on page 167.
Driving through water
Do not drive through water on the
road if it is deeper than 1 ft/30 cm,
and then only at walking speed at the most.
Otherwise, the vehicle's engine, the electri-
cal systems and the transmission may be
damaged.<
Braking safely
Your BMW is equipped with ABS as stan-
dard. The best way to achieve optimized
braking response from the ABS is to apply
maximum pressure to the brake pedal in
situations where this is required: panic
stops. Since the vehicle maintains steering
responsiveness, you can nevertheless
avoid possible obstacles with a minimum
of steering effort.
Pulsation at the brake pedal combines with
sounds from the hydraulic circuits to indi-
cate to the driver that ABS is in its active
mode.
Do not drive with your foot resting on
the brake pedal. Even light but con-
sistent pedal pressure can lead to high
temperatures, brake wear and possibly
even brake failure.<
Driving in wet conditions
While driving in wet conditions and in
heavy rain, it is a good idea to apply light
pressure to the brake pedal every few
miles. Monitor 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 full braking efficiency will then
be available when you need it.
Hills
To prevent overheating and thus
reduced efficiency of the brake sys-
tem, downshift to a gear in which only min-
imal brake applications are needed when
descending long or steep downhill
stretches. Even light but consistent pedal
pressure can lead to high temperatures,
brake wear and possibly even brake fail-
ure.<
You can further enhance the engine's brak-
ing effect by selecting a lower gear in the
automatic transmission's manual mode,
downshifting as far as first gear on
extremely steep stretches, refer to
page 59. This strategy helps you avoid
placing excessive loads on the brake sys-
tem.
Never drive with the clutch pressed
or allow the vehicle to coast with the
transmission in Neutral – or with the engine
switched off – there is no engine braking
when the transmission is in Neutral, and no
power assist for brakes and steering when
the engine is not running.
Never allow floor mats, carpets or any other
objects to protrude into the area around the
accelerator and brake pedals and obstruct
their movement.<
Corrosion on brake rotors
When the vehicle is driven only occasion-
ally, during extended periods when the
vehicle is not used at all, and in operating
conditions where brake applications are
less frequent, there is an increased ten-
dency for corrosion to form on rotors, while
contaminants accumulate on the brake
pads. This occurs because the minimum
pressure which must be exerted by the
pads during brake applications to clean the
rotors is not reached.
Should corrosion form on the brake rotors,
the brakes will tend to respond with a pul-
sating effect that even extended applica-
tion will fail to cure.

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Engine compartment
1Filler neck for engine oil, refer to
Topping up engine oil
2Brake fluid reservoir, located beneath
the microfilter cover, refer to page 173
3Dipstick for engine oil, refer to
Checking oil level
4Starting-aid terminal, refer to page 184
5Washer fluid reservoir of the headlamp
and windshield cleaning systems, refer
to page 62
6Expansion tank for coolant, refer to
page 172
Engine oil
Checking oil level
1.Park the vehicle on a level surface with
the engine at operating temperature
2.After approx. 5 minutes, pull the
dipstick 3 out and wipe it off with a
clean lint-free cloth, paper towel, or
similar material3.Carefully push the dipstick all the way
into the guide tube and pull it out again
4.The oil should extend to between the
two marks on the dipstick.
The engine oil consumption is dependent
on driving style and driving conditions.
The oil quantity between the centers of the
two marks on the dipstick, refer to arrows,
is approx. 1.6 US quarts/1.5 liters. Do not
fill beyond the upper mark on the dipstick.
Excess oil can damage the engine.

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3.The coolant level is correct when the
measuring range of the fill level indica-
tor is at the level of the upper edge of
the filler neck, also refer to the drawing
next to the filler neck
4.If the coolant is low, slowly add coolant
up to the specified level – do not overfill
5.Turn the cap until you hear a click
6.Have the reason for the coolant loss
eliminated as soon as possible.
Brake system
Malfunction
Brake fluid
The warning lamp lights up in red
in spite of the handbrake being
released; a message appears on
the Control Display.
Stop the vehicle immediately.
The brake fluid in the reservoir has fallen to
below the minimum level. At the same time,
a significantly longer brake pedal path is
noticeable. Have the system checked
immediately by a BMW center.
Warning lamp for Canadian models.
When you continue driving, an
increased brake pedal path can be
necessary, and significantly longer braking
distances might be required. Please adapt
your driving style accordingly.<
Brake pads
The warning lamp lights up in red
in spite of the handbrake being
released; a message appears on
the Control Display. The brake pads have
reached their minimum pad thickness.
Have the brake pads replaced as soon as
possible.
Warning lamp for Canadian models.For your own safety: use only brake
pads that BMW has approved for your
particular vehicle model. As BMW cannot
assess the suitability of other brake pads
for use on your vehicle, BMW is unable to
assume continued responsibility for the
vehicle's operating safety if non-approved
pads are installed.<