2004 BMW 645CI COUPE&CONVERTIBLE engine

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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repealed, even with DSC.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

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have dropped below the minimum, possi-
bly owing to a leak in the hydraulic system.
Do not continue driving. Contact your BMW
center.<
Flat Tire Monitor
The concept
The Flat Tire Monitor keeps track of the
inflation pressures in the four tires as you
drive. The system provides an alert when-
ever the inflation pressure drops signifi-
cantly in relation to the pressure in another
tire.
The check of the tire inflation pressure is
based on monitoring the relative speeds
of the wheels. A flat tire is detected and
reported on the basis of a deviation in cer-
tain speed ratios.
Functional requirement
To ensure reliable operation, the system
should have been initialized with the cor-
rect tire inflation pressure.
System limits
The Flat Tire Monitor cannot indicate
sudden severe tire damage caused
by outside factors and does not detect a
natural, even pressure drop in all four
tires.<
In the following situations, the system
could be delayed or malfunction:
>When you are driving on snow-covered
or slippery road surfaces
>In the case of performance-oriented
driving: slip on the drive wheels, high
lateral acceleration
>False alarms and undetected loss of
pressure may occur when you are driv-
ing with snow chains fitted
>If the Flat Tire Monitor was not initial-
ized after the last inflation pressure cor-
rection, false alarms indicating a flat tire
that is not present are possible or pres-
sure loss might not be detected.
Initializing system
Perform the initialization immediately
after correcting the inflation pressure,
after changing a tire or changing a wheel or
all wheels. A drive is necessary for this pur-
pose.<
Control Center, for principle details, refer to
page 16:
1.Start the engine, but do not drive off
2.Open the menu
3.Select "Vehicle settings" and press the
controller
4.Select "FTM" and press the controller
5.Select "Set tire pressure" and press the
controller
6.Select "Yes" and press the controller
7.Drive off.
The message "Initializing" is displayed.
It takes a few minutes before the Flat Tire
Monitor can detect and report a flat tire and
"Status: Active" is displayed.
If a flat tire is detected during initialization,
a message appears on the Control Display.
When driving with snow chains, do
not initialize the system.<

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.

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14Indicator lamp for independent ventila-
tion
>Activation time set:
The indicator lamp comes on
>Independent ventilation switched on:
The indicator lamp flashes
15Rear window defroster
16Air grill for interior temperature sensor –
please keep clear and unobstructed
All other setting options for the automatic
climate control can be found at "Climate"
and in the menu on the Control Display,
refer to pages 90 and 91.
The current setting for air distribution is dis-
played on the Control Display.
A congenial climate
To use the automatic function, press the
AUTO button. Select an interior tempera-
ture you find pleasant.
The following section contains more
detailed information on the available set-
ting options.
The cooling function is only possible with
the engine running.
AUTO program
The AUTO program adjusts the
air distribution to the wind-
shield and side windows,
towards the upper body and footwell as
well as the air volume, while also using your
preselected temperature setting as the
basis for adjusting the interior climate to
adapt to external seasonal influences.
The cooling function comes on automati-
cally when you select the AUTO program.
At the same time, a condensation sensor
controls the program in such a way that
window condensation is prevented as far
as possible.
Temperature adjustment
The figures on the display pro-
vide a general indication of inte-
rior temperature. A pleasant
adjustment is 727/226.
When you start the vehicle, this system ensures that the selected tempera-
ture is achieved as quickly as possible. It
then maintains this temperature, regard-
less of the season.
Defrosting windows and removing
condensation
This program quickly removes
ice and condensation from the
windshield and front side win-
dows.
Adjusting air volume manually
You can adjust the air volume
by turning. You can reactivate
the automatic mode for the air
volume with the AUTO button.
Switching cooling function on and off
manually
The cooling function cools and
dehumidifies the incoming air
before also reheating it as
required, according to the temperature set-
ting. Depending on the weather, the wind-
shield may fog over briefly when the engine
is started.
The cooling function comes on automati-
cally when you select the AUTO program.
Maximum cooling
This program quickly provides
maximum cooling.
The system switches to the
recirculated-air mode and the
air flows at maximum air volume only from
the vent outlets for the upper body area.
For this reason you should ensure that
these vent outlets are open before select-
ing this program.
AUC Automatic recirculated-air
control
You can respond to unpleasant
odors or pollutants in the imme-
diate environment by tempo-
rarily suspending the supply of outside air.
The system then recirculates the air cur-

A congenial climate
90 rently within the vehicle. AUC executes this
function automatically.
Press the button repeatedly to run through
the following control sequence:
>Indicator lamps off: outside air flows
into the vehicle continuously
>Right indicator lamp on, AUC mode: the
system detects pollutants in the outside
air and responds by blocking the supply
of outside air when required.
Depending upon air quality require-
ments, in the automatic mode the sys-
tem alternates between its outside-air
and recirculated-air modes
>Left indicator lamp on, recirculated-air
mode: the supply of outside air into the
vehicle is continuously blocked.
If condensation starts to form on the
inside window surfaces during opera-
tion in the recirculated-air mode, you
should switch it off while also increasing
the air volume as required.
The recirculated-air mode should not be
used over a longer period of time, as the air
quality inside the vehicle deteriorates con-
tinuously.<
Residual heat mode
If you press this button with the
engine switched off, the system
uses the warmth stored in the
engine to heat the interior, for
instance, while the vehicle is
stationary at a school to pick up a child.
You can adjust the automatic climate con-
trol settings as of ignition key position 2.
Provided that the engine has warmed to its
normal operating temperature and the bat-
tery is charged, you can use this function
for up to 15 minutes after switching off the
ignition. The LED within the button lights up
to confirm compliance with both of these
conditions.
Switching off automatic climate
control
The air volume, the heater and
the cooling function are all
switched off. You can restart
the automatic climate control
by pressing any of its buttons
except the REST button.
Settings using Control Center
Ignition key:
>On vehicles with separate drives for
audio CDs and navigation DVDs, igni-
tion key in position 2
>On vehicles with one drive for audio
CDs, ignition key in position 1.
Control Center, for principle details, refer to
page 16:
1.Press button.
The start menu is opened
2.Move the controller to the left to open
"Climate".
You can set the following:
>Separate air distribution for driver and
front passenger
>Adapting the temperature in the upper
body region
>Intensity of the AUTO program.
Manual air distribution
You can combine your air distribution your-
self and also individually adjust the air tem-
perature in the upper body area.

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.