2005 BMW 645CI COUPE&CONVERTIBLE brake

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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
64
Displays in instrument cluster
1Stored desired speed display
2Detected vehicle display.
Lights up when vehicle driving ahead is
detected
3Selected distance to vehicle driving ahead
4Digital speed display.
Appears briefly when you select your
desired speed
The system is activated.
The display3 appears as soon as
you activate the system and no
vehicle is detected driving ahead.
Vehicle detected.
The display2 lights up yellow
when a vehicle is detected driving
ahead.
The system requests that you
intervene by braking or with an
evasive maneuver.
The display2 flashes red and a sig-
nal sounds. The active cruise con-
trol cannot automatically restore the distance to
the vehicle driving ahead. You will find more
detailed information on page67.
Automatic intervention by ABS or
DSC, or you actuate the parking
brake while driving.
The display2 flashes yellow. The
active cruise control now only
intervenes by braking.
Desired speed store and increase
Press the lever forward1 at a driving speed of
more than approx. 20 mph/30 km/h:
The system adopts and stores your current
speed as a desired speed. This speed is indi-
cated on the speedometer and displayed briefly
in the instrument cluster.
Subsequently pressing forward increases the
desired speed to the next multiple of 5 mph/
10 km/h.
Each time the lever is pressed forward again,
the desired speed is increased by another
5 mph/10 km/h until a maximum of 110 mph/
180 km/h is reached. The speed then displayed
is stored and achieved, provided that the road is
clear.
If the display ACC --- mph/km/h briefly
appears in the instrument cluster, it might
be that conditions necessary for operation are
not currently being met.
To call up Check Control messages, refer to
page71.<
Desired speed store and decrease
Pull back the lever2:
The current driving speed is rounded off to the
next multiple of 5 mph/10 km/h, displayed and
stored.
Each time the lever is pulled back again, the
desired speed is decreased by another 5 mph/
10 km/h until the minimum speed of 20 mph/
30 km/h is reached. The speed then displayed
is stored and achieved, provided that the road is
clear.

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Deactivate system
Press the lever up or down while the system is
active3. The displays in the instrument cluster
disappear. You can use the system again as
required.
In addition, the system is deactivated automati-
cally:
>When you apply pressure to the brake pedal
>When you select the automatic transmis-
sion's/SMG neutral position N
>When the manual transmission is in neutral
>When you deactivate the DSC Dynamic
Stability Control
>When you actuate the parking brake during
driving
>When the system reduces the speed to
below 20 mph/30 km/h due to a traffic situ-
ation
The system deactivates automatically
when the speed is set to below 20 mph/
30 km/h. An acoustic signal sounds and a mes-
sage appears on the Control Display. The active
intervention of the driver is required.<
When you switch off the ignition, the stored
desired speed is deleted.
Resume to stored desired speed and
distance setting
Press button4 when the system is deactivated.
The displays appear in the instrument cluster.
The system is reactivated and uses the last
stored desired speed and distance setting.
Fine adjustment of desired speed
In the activated state, the desired speed
increases by 1 mph/1 km/h each time button4
is pressed briefly.
Select distance
You can choose from four distance steps.
>Rotary switch downward:
Increase distance.
>Rotary switch upward:
Decrease distance.
The selected distance is displayed in the instru-
ment cluster.
Distance 1
Distance 2
Distance 3
This distance is always set when
the system is used for the first time
after starting the engine.
Distance 4
Use good judgment to select the appro-
priate following distance given road con-
ditions, traffic, applicable laws and driving rec-
ommendations for safe following distance.<

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.

Technology for comfort, convenience and safety
82 Do not reduce the pressure on the brake pedal
for the duration of the brake application. When
the brake pedal is released, DBC is deactivated.
DSC Dynamic Stability Control
The system prevents slip at the drive wheels
when driving off and accelerating. DSC also
detects unstable driving conditions such as
fishtailing or sliding of the front wheels. In these
cases DSC helps the vehicle safely stay on
course within the physical limits by reducing the
engine output and through braking actions in
the individual wheels.
The DSC is operational every time you start the
engine.
The laws of physics cannot be repealed,
even with DSC. An appropriate driving
style always remains the responsibility of the
driver. Therefore, do not reduce the additional
safety margin again by taking risks.<
DTC Dynamic Traction Control
DTC is a variant of DSC for special road condi-
tions, e.g. uncleared snow-covered roads, that
is optimized for forward momentum. The sys-
tem ensures maximum forward momentum, but
with limited driving stability. Therefore, drive
with the corresponding caution.
You may find it useful to briefly activate DTC
under the following special circumstances:
>When driving on snow-covered uphill
grades, in slushy snow or on uncleared,
snow-covered roads
>When rocking a stuck vehicle free or when
starting off in deep snow or on loose ground
>When driving with snow chains
*
Activating DTC
Press the button; the DTC indicator lamp in the
instrument cluster lights up.
Deactivating DTC again
Press the button again; the DTC indicator lamp
in the instrument cluster goes out.
Deactivating DTC and DSC together
Press the button until the DSC indicator lamp in
the instrument cluster lights up, however not
longer than approx. 10 seconds. Interventions
promoting stability and forward momentum will
no longer be carried out. In addition, the stability
promoting intervention of the active steering
*
is deactivated, refer to page85.
A message appears on the Control Display.
Please note any supplementary information
that appears there.
To support enhanced operating stability, reacti-
vate DSC again as soon as possible.
Reactivating DSC
Press the button; the indicator lamp in the
instrument cluster goes out.

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To control
The indicator lamp flashes:
DSC or DTC controls the drive forces
and brake forces.
The indicator lamp comes on:
DSC and DTC are deactivated together via the
button DTC.
The indicator lamp comes on: DTC is
activated via the DTC button.
Malfunction in the 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 Dis-
play. The driving-stability control sys-
tems have failed. Conventional braking
efficiency remains available without
limitations.
While you may continue, you should remember
to proceed cautiously and drive defensively
while avoiding full brake applications.
Have the system checked as soon as possible.
Display of the previously described
malfunction on Canadian models.
The DSC indicator lamp lights up. A
message appears on the Control Dis-
play. A malfunction has occurred in
DSC and DTC.
The stability maintenance functions are no
longer available. The vehicle remains opera-
tional.
Have the system checked as soon as possible.
The warning lamp for the brake system
lights up in yellow. A message appears
on the Control Display. DBC has failed.
Have the system checked as soon as possible.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 cornering and
evasive maneuvers.
Dynamic stabilizers at the front and rear axles
form the basis for active roll stabilization. Sus-
pension compliance adapts to suit driving con-
ditions, varying from performance-oriented
during cornering to smooth and comfort-ori-
ented when the vehicle is proceeding in a
straight line. During vehicle operation, the sys-
tem continuously 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 mes-
sage 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 tendency to tilt
during cornering and in crosswinds.
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 have dropped
below the minimum, possibly owing to a leak in
the hydraulic system. Do not continue driving.
Contact your BMW center.<