2005 BMW 645CI CONVERTIBLE brakes

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SMG Sequential manual transmission*
and automatic transmission*
Your BMW is equipped with the convenience
starting feature. It is sufficient to turn the igni-
tion key only briefly to position 3 and then
release it right away. The system responds by
automatically engaging the starter for a certain
period and allowing it to run until the engine
starts, after which it then disengages automati-
cally.
SMG Sequential manual transmission*
1.Press the brake pedal.
2.Engage selector-lever position N.
3.Start the engine.
If the engine does not start, engage the
last gear selected again, refer to instru-
ment cluster display, and then shift into posi-
tion N.<
Automatic transmission with
Steptronic*
1.Press the brake pedal.
2.Engage selector-lever position P or N.
3.Start the engine.
Switching off engine
Do not remove the ignition key while the
vehicle is rolling, as otherwise the steer-
ing wheel lock will immobilize the steering.
When leaving the vehicle, remove the ignition
key and lock the steering.
When parking on a downhill incline, apply the
handbrake, as otherwise the vehicle could roll
away.<
Manual transmission
1.Turn the ignition key to position 1 or 0.
2.Shift into first gear or reverse.
SMG Sequential manual transmission*
1.Engage a drive position.
2.Turn the ignition key to position 1 or 0.
A signal sounds on stopping the engine.
Automatic transmission with
Steptronic*
1.Engage selector-lever position P.
2.Turn the ignition key to position 1 or 0.
Handbrake
The handbrake is primarily intended to prevent
the vehicle from rolling while parked; it brakes
the rear wheels.
Indicator lamp
The indicator lamp lights up, and an
acoustic signal also sounds when start-
ing off. The handbrake is engaged.
Indicator lamp for Canadian models.
Engaging
The lever engages automatically.
Releasing
Pull slightly upward, press the button and lower
the lever.
If exceptional circumstances should
make it necessary to engage the hand-
brake while the vehicle is in motion, do not pull it
too strongly. In doing so, continuously press the
button of the handbrake lever.
Strong application of the handbrake can lead to
overbraking of the rear axle and associated
'fishtailing' of the vehicle rear end.
The brake lamps do not light up when the hand-
brake is engaged.

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cially on longer trips, the system can reduce
fatigue and tension, while increasing your
enjoyment of driving. Please use it safely and
responsibly.
In addition to holding a steady cruising speed, if
you encounter slower vehicles ahead, active
cruise control will, within the scope of given
possibilities, adjust your vehicle's speed auto-
matically so that one can flow with the traffic
without having to make constant adjustments.
If, for example, while cruising at the selected
speed, you begin to approach a slower vehicle
ahead of you in the same lane, the system will
reduce your vehicle's speed to the same as that
of the vehicle ahead to maintain your selected
distance setting between your vehicle and the
vehicle ahead. There are four settings for dis-
tance, which are additionally speed-dependent.
Based on your selected distance setting, the
system automatically decreases the throttle
setting and lightly applies the brakes if neces-
sary. The vehicle brake lamps will automatically
illuminate to signal a following driver to take
action. In addition, it may be necessary for the
vehicle or the driver to downshift, depending on
the kind of transmission your vehicle is
equipped with, to maintain the distance setting
selected. If the vehicle ahead speeds up or
when the lane ahead becomes clear, your vehi-
cle will accelerate to the speed you have
selected by increasing the throttle setting and
shifting gears automatically or by the driver as
needed.
Active cruise control is not and must not
be used as a collision avoidance/warning
system.<
Since this active cruise control system is
a new technology and operates differ-
ently from conventional cruise control systems
which you may be accustomed to, you are
strongly urged to read all of the pages relating
to this system before use. Pay special attention
to the information contained in the Things to
know about active cruise control section in this
manual beginning on page66. You can use the system in the 2nd to 6th gear
within a normal engine speed range and also
change gears. Continuous operation at very
high or very low engine speeds is not possible.
In this case the driver is asked to shift or the
system deactivates itself.
Vehicles with SMG
Continuous operation at very high engine
speeds is not possible in the Sequential mode.
In this case the driver is asked to shift or the
system deactivates itself.
In the Drive mode the SMG acts similarly to the
automatic transmission in the D position.
Operating active cruise control
1Activate system, store and increase desired
speed
2Activate system, store and decrease
desired speed
3Deactivate system
4Recall the stored speed and distance or
increase desired speed by 1 mph/1 km/h
with each press of the button
5Select distance to vehicle driving ahead.
You can choose from four available distance
settings. You will find more detailed infor-
mation on page65.
Adjust your desired speed to the traffic
conditions and remain ready to brake at
all times. Great differences in speed to the vehi-
cles driving ahead, e. g. when quickly approach-
ing a truck or when another vehicle swerves into
your lane, cannot be compensated for by the
system.<

Driving
66
Things to know about active cruise control
As with conventional cruise control sys-
tems, active cruise control in no way
diminishes or substitutes for the driver's own
personal responsibility, alertness and aware-
ness in adjusting speed, braking or otherwise
controlling the vehicle. The driver should
decide when to use the system on the basis of
road, traffic, visibility, and weather conditions.
Active cruise control is intended for use on
highway-type roadways where traffic is moving
relatively smoothly. Do not use this system in
city driving; heavy traffic such as during rush
hour; on curvy, winding roads, slippery roads or
roads with sharp curves such as highway off-
ramps; during inclement weather such as snow,
strong rain or fog; or when entering inter-
changes, service/parking areas or toll booths.
It is also important to regulate your vehicle's
speed and distance setting within applicable
legal limits. Always be ready to take action or
apply the brakes if necessary, especially when
the system is actively following a vehicle in front
of you.<
Always remember that the range and abil-
ity of the system does have physical limi-
tations. It will not apply the brakes or decelerate
your vehicle when there is a slow-moving vehi-
cle, stopped vehicle or stationary object ahead
of you, as for example, at a traffic light or when
approaching a parked vehicle. Also, the system
does not react to oncoming traffic, pedestrians
or other types of potential traffic such as a rider
on horseback. It is also possible that the system
may not detect smaller moving objects such as
motorcycles or bicycles. Be especially alert
when encountering any of these situations as
the system will neither automatically brake, nor
provide a warning to you. Also, be aware that every decrease in the distance setting allows
your vehicle to come closer to a vehicle in front
of you and requires a heightened amount of
alertness.<
If your vehicle is actively following a vehicle in
front of you and the vehicle ahead speeds up or
the lane ahead becomes clear, then your vehi-
cle will accelerate to the speed you have
selected. Be aware that changing to a clear,
unobstructed lane will also result in your vehicle
accelerating.
Be certain to deactivate the system when
you pull into an exit lane for a highway off-
ramp.<
Also, vehicles traveling in a staggered manner
on a highway may cause a delay in the system's
reaction to a vehicle in front of you or may cause
the system to react to a vehicle actually in the
lane next to you. Always be ready to take action
or apply the brakes if necessary.
Active cruise control can only decelerate the
vehicle to approx. 20 mph/30 km/h. If the sys-
tem reduces vehicle speed below 20 mph/
30 km/h or if DSC/ABS is engaged while driving,
the system will automatically deactivate.
Remember, the system cannot stop your
vehicle. In addition, the system is deacti-
vated whenever the driver applies the vehicle
brakes, shifts the transmission to neutral/N, or
deactivates DSC. After any deactivation, the
system will no longer automatically activate the
vehicle brakes, which means the driver must
intervene and resume manual braking. You
should then reactivate the system only when
you are fully aware of the prior speed and dis-
tance settings.<

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Active cruise control may brake when you
reduce the stored desired speed; however, the
driver must constantly monitor traffic and inter-
vene if necessary.
When you switch off the engine or ignition,
active cruise control is fully switched off, too,
and any settings you have selected are can-
celed.
Behavior in curves
Because of the limited range of the system, it is
possible that in curves or on the peaks and val-
leys of hilly roads, a vehicle ahead may be rec-
ognized late, or not at all. Therefore, it is up to
the driver to select a speed that is prudent in
view of the curves and terrain of the roadway.
In approaching a curve, it is possible that active
cruise control would react briefly to a vehicle in
the adjacent lane. In addition, the system can
sense if your vehicle is in a curve and may not
accelerate. If your vehicle decelerates in either
case, you can choose to overcome the deceler-
ation by briefly pressing the accelerator pedal.
Driver interventions
Anytime the driver presses down on the
accelerator pedal, any automatic braking
action by the system is interrupted until the
pedal is fully released. After doing this, release
the accelerator and the system again controls
your cruising speed and distance setting. While
driving with activated system, resting your foot
on the accelerator pedal will cause the system
not to brake even if necessary. Be certain that
floormats or other objects on the vehicle floor
do not interfere with movement of the accelera-
tor pedal.<
While active cruise control is capable of
braking your vehicle automatically when
you approach a slower vehicle ahead, it is
important to be aware that the ability of the sys-
tem to apply the brakes is also limited, if you are
driving down a steep grade or when you reduce
your desired speed sharply. The system cannot
stop your vehicle. It uses only a portion of brak-
ing system capacity and does not utilize the full
capacity of the vehicle braking system. There-
fore, the system cannot decrease your speed
for large differences in speed between your
vehicle and the vehicle ahead. Examples: during
emergency braking, when you approach a vehi-
cle traveling at a much lower speed than your
own speed such as when approaching a toll
booth or when a much slower vehicle cuts in
front of you at close range.<
Whenever active cruise control
recognizes a situation that requires
driver braking because the system
capacity has been reached or has
been exceeded, the system alerts
the driver by flashing this symbol in the instru-
ment cluster and sounding a signal.

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1.Press button.
This opens the start menu.
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.
The setting is stored for the remote control cur-
rently in use.
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 ultra-
sonic measurement, such as those encoun-
tered with thin and wedge-shaped objects, etc.
Low objects already displayed, e.g. a curb, can
also disappear from the detection area of the sensors again before a continuous tone
sounds.
Loud noises from outside and inside your vehi-
cle may prevent you from hearing the PDC sig-
nal 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.
ABS Antilock Brake System
ABS prevents the wheels from locking during
braking. Safe steering response is maintained
even during hard braking. This increases active
driving safety.
ABS is operational every time you start the
engine. For information on safe braking, refer to
page109.
CBC Cornering Brake Control
This system provides further enhancements to
vehicle stability and steering response when
braking while cornering or when braking during
a lane change.
Electronic brake-force distribution
This system controls the brake system's appli-
cation pressure at the rear wheels to ensure
stable deceleration.
DBC Dynamic Brake Control
When you apply the brakes rapidly, this system
automatically produces the maximum braking
force boost and thus helps to achieve the short-
est possible braking distance during panic
stops. This system exploits all of the benefits
provided by ABS.

Things to remember when driving
108
Things to remember when driving
Breaking-in
Moving parts need time to adjust to one
another. 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 follow-
ing 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 4,500 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 kick-down 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 during the
break-in period, refer to page59.
Tires
Due to technical factors associated with their
manufacture, tires do not achieve their full trac-
tion 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 optimized
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 mentioned
above need to be replaced at a later point.
General driving notes
Close the luggage compartment lid
Operate the vehicle only when the lug-
gage compartment lid is completely
closed. Otherwise, exhaust fumes could pene-
trate to the interior of the vehicle.<
If special circumstances should make it abso-
lutely necessary to operate the vehicle with the
luggage compartment lid open:
1.Coupe: close both windows and the glass
sunroof.
Convertible: with closed top, close all win-
dows.
2.Adjust the automatic climate control to sup-
ply a high air volume, refer to page95.
Hot exhaust system
As in all vehicles equipped with a catalytic
converter, extremely high temperatures
are generated in this vehicle. Do not remove the
heat shields installed adjacent to various sec-
tions of the exhaust system, and never apply
undercoating to them. When driving, standing
at idle and while parking, take care to avoid pos-
sible 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 property dam-
age as well as personal injury.<

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Mobile communication devices in
vehicle
BMW advises against using mobile com-
munication devices, e.g. portable phones,
inside the vehicle without a direct connection to
an external antenna. Otherwise, the vehicle
electronics and mobile communication device
can influence one another. In addition, there is
no assurance that the radiation emitted during
transmission will be conveyed out of the vehicle
interior.<
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 sur-
face. This phenomenon is referred to as hydro-
planing, and is characterized by a partial or
complete loss of contact between the tires and
the road surface, ultimately 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 Mini-
mum tire tread on page171.
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 vehi-
cle's engine, the electrical systems and the
transmission may be damaged.<
Using handbrake on inclines.
On inclines, do not hold the vehicle with
the clutch; use the handbrake. Otherwise
greater clutch wear will result.<
SMG Sequential manual transmission
Start off quickly on slopes. Do not hold
the vehicle on a hill by applying the throt-
tle, but engage the handbrake instead. Other-
wise overheating can occur in the transmission
region.<
Braking safely
Your BMW is equipped with ABS as standard. In
situations that require it, it is best to brake with
full force. Since the vehicle maintains steering
responsiveness, you can still avoid possible
obstacles with a minimum of steering effort.
Pulsation at the brake pedal combines with
sounds from the hydraulic circuits to indicate to
the driver that ABS is in its active mode.
Do not drive with your foot resting on the
brake pedal. Even light but consistent
pedal pressure can lead to high temperatures,
brake wear and possibly even brake failure.<
Driving in wet conditions
When driving on wet roads or in heavy rain,
briefly brake with light pedal pressure at inter-
vals of a 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 system, downshift
to a gear in which only minimal brake applica-
tions are needed when descending long or
steep downhill stretches. Even light but consis-
tent pedal pressure can lead to high tempera-
tures, brake wear and possibly even brake fail-
ure.<
You can further enhance the engine's braking
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 page58. This strategy helps you avoid
placing excessive loads on the brake system.
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.

Things to remember when driving
110 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 occasionally,
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 tendency 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 pulsating
effect that even extended application will fail to
cure.
When the vehicle is parked
Condensation forms in the automatic air condi-
tioner system during operation, and then exits
under the vehicle. Traces of condensed water
under the vehicle are therefore normal.
Before driving into a car wash
To prevent the exterior mirrors from being
damaged due to the width of the vehicle,
always fold them in by hand before entering an
automatic car wash.<
Cargo loading
To avoid loading the tires beyond their
approved carrying capacity, never over-
load the vehicle. Overloading can lead to over-
heating and increases the rate at which damage
develops inside the tires. The ultimate result
can assume the form of a sudden blow-out.<
Determining loading limit
1.Locate the following statement on your
vehicle's placard
*:
The combined weight of occupants
and cargo should never exceed
XXX lbs. or YYY kg, as otherwise the vehicle
may be damaged and unstable driving con-
ditions may result.<
2.Determine the combined weight of the
driver and passengers that will be riding in
your vehicle.
3.Subtract the combined weight of the driver
and passengers from XXX lbs. or YYY kg.
4.The resulting figure equals the available
amount of cargo and luggage load capacity.
For example, if the XXX amount equals
800 lbs. and there will be four 150-lbs. pas-
sengers in your vehicle, the amount of avail-
able cargo and luggage load capacity is
200 lbs.:
800 lbs. minus 600 lbs. = 200 lbs.
5.Determine the combined weight of luggage
and cargo being loaded on the vehicle. That
weight may not safely exceed the available
cargo and luggage load capacity calculated
in step 4.
6.If your vehicle will be towing a trailer, part of
the load from your trailer will be transferred
to your vehicle. Consult the manual for
transporting a trailer to determine how this
may reduce the available cargo and luggage
load capacity of your vehicle.