2005 BMW 645I CONVERTIBLE engine

Driving
58
Automatic transmission with
Steptronic*
In addition to the fully automatic mode, you can
also shift manually with Steptronic, refer to
page58.
Selector-lever positions
P R N D M/S + –
Displays in instrument cluster
P R N D DS M1 to M6
The selector lever position is indicated, and in
the manual mode, the gear currently engaged.
Changing the selector-lever positions
An interlock prevents inadvertent gearshifts
into selector-lever positions R and P. To cancel
the interlock, press the button on the front of
the selector lever knob, refer to arrow.
Shiftlock
Press the brake pedal before shifting out of P
or N; the shift command will not be executed
unless the brake is applied.
To prevent the vehicle from creeping after you
select a driving position, maintain pressure on
the brake pedal until you are ready to start.To prevent the vehicle from rolling,
always select selector-lever position P
and engage the handbrake before leaving the
vehicle with the engine running.
Never leave an unattended vehicle with the
engine running, as such a vehicle represents a
potential safety hazard.<
P Park
Select only when the vehicle is stationary.
The rear wheels are locked.
R Reverse
Select only when the vehicle is stationary.
N Neutral
Engage in car washes, for example. The vehicle
can roll.
D Drive, automatic position
Position for normal vehicle operation.
All forward gears are available.
Under normal operating conditions, fuel con-
sumption is lowest when driving in position D.
Kick-down
The kick-down mode provides maximum accel-
eration:
Press the accelerator pedal beyond the full-
throttle resistance point.
M/S manual operation and
Sport program
Move the selector lever from position D to the
left into shifting slot M/S:
The sport program is activated and DS appears
in the instrument cluster. This position is

Controls
59Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
recommended for a performance-oriented driv-
ing style. It is engaged automatically when the
Dynamic Driving Control is activated, see
below.
When the selector lever is briefly moved for-
ward or back, the manual mode is activated and
the Steptronic shifts gear. The instrument clus-
ter shows M1 through M6.
Upshifts and downshifts are executed only
when they will result in a plausible combination
of engine and vehicle speed; thus, for example,
a downshift that would cause the engine to
overrev will not be executed by the system. The
selected gear appears briefly in the instrument
cluster, followed by the current gear.
To use the automatic function again, move the
selector lever to the right into position D.
Dynamic Driving Control
The Dynamic Driving Control makes it possible
for your BMW to react in an even more perfor-
mance-oriented manner at the push of a button:
>The engine responds more spontaneously
to accelerator pedal movements.
>Cruise control:
The stored speed is reached more quickly
when it is requested.
Additionally with SMG:
>Gearshifts are faster.
>The engine speed range is used optimally in
the Drive mode.
With automatic transmission:
>The Sport program is activated.
Activating system
In ignition key position 2, press the SPORT but-
ton.
The LED in the button lights up and SPORT is
displayed in the instrument cluster.
Deactivating system
>Press the SPORT button again or
>engage reverse gear or
>switch off the engine.
The LED in the button and SPORT in the instru-
ment cluster go out.
Acceleration assistant with SMG
The acceleration assistant enables optimized
vehicle acceleration at racing car level on road
surfaces with good adhesion when starting off.
Do not use the acceleration assistant too
often, as otherwise components will wear
prematurely.<
1.Activate the Dynamic Driving Control.
2.Press the DTC button, refer to page82, for
longer than three seconds.
3.Press the accelerator pedal down fully:
Kick-down. The ideal starting-off engine
speed is set.
To maintain driving stability, do not deac-
tivate DSC if at all possible.<

Driving
62
One lever for all functions
1Maintaining speed, storing speed, and
accelerating
2Maintaining speed, storing speed, and
decelerating
3Interrupting cruise control
4Recalling stored speed
Maintaining speed, storing speed, and
accelerating
Press the lever up to the resistance point1:
The system maintains and stores the current
vehicle speed. The display 1 in the speedome-
ter indicates this regulated speed, refer to the
section below. Every time you briefly press the
lever, the vehicle speed increases by roughly
1mph/1km/h.
Press the lever up to the resistance point and
hold it:
The vehicle accelerates without pressure on
the accelerator pedal. The system maintains
and stores your current speed as soon as you
release the lever.
Press the lever beyond the resistance point:
The speed increases by 5 mph/10 km/h.
The vehicle may accelerate beyond the regu-
lated speed on steep downhill stretches where
the engine's braking effect alone may not be
sufficient to slow the vehicle. Speed can drop
on uphill grades if the engine output is insuffi-
cient.
Maintaining speed, storing speed, and
decelerating
Pull the lever2:
Functions are the same as 1, only the vehicle
speed is reduced.
Interrupting cruise control
With the cruise control active, briefly press the
lever up or down3.
Cruise control is also interrupted automatically
>when you apply pressure to the brake pedal
>when you press down the clutch pedal or
engage position N of the automatic trans-
mission/SMG
>when DSC comes on
Recalling stored speed
Briefly press button4: the vehicle accelerates
to and maintains the stored speed.
Deactivating system
When the ignition is switched off, the system is
deactivated and the stored speed is deleted.
Displays in instrument cluster
1Display for stored speed
2Brief display of selected speed
Active cruise control*
The concept
With active cruise control, you can select a
desired speed which is not only automatically
maintained when driving on open roadways, but
also varied to maintain a selected distance set-
ting as slower traffic is encountered.
Active cruise control is a technological advance
over the familiar cruise control and is a welcome
relief from the constant adjustment of speed
that can accompany driving in traffic on free-
ways or other high-speed thoroughfares. Espe-

Controls
63Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
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.<

Controls
65Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
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.<

Controls
67Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
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.

Controls
69Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
Everything under control
Odometer, outside
temperature display, clock
When the ignition is off you can briefly activate
the time, outside temperature and odometer
displays by pressing the knob3 at the lower left
of the instrument cluster.
1 Outside temperature display, clock,
date
The outside temperature and the time are dis-
played from ignition key position 1 onwards.
To call up the date:
Press the CHECK button on the turn signal
lever, refer to page74.
Setting time and date, refer to page78.
You can set the measurement unit 7 or 6 on
the Control Display, refer to Measurement units
on page77.
Ice warning
A signal sounds when the outside temperature
falls to roughly +37.57/+36; this is accompa-
nied by a message.
Please bear in mind that the ice warning
does nothing to alter the fact that black
ice may be present on roads at temperatures
higher than +37.57/+36, e.g. on bridges and
shaded roads.<
2 Odometer and trip odometer
To reset the trip odometer to zero:
Press button3 in the instrument cluster.
Tachometer
The white-striped advance warning field,
arrow1, changes depending on the engine
temperature. The segments disappear in
sequence as the engine warms to its normal
operating temperature.
Avoid allowing the engine speed to rise as far as
the advance warning field whenever possible.
Engine speeds in the red warning field, arrow2,
must absolutely be avoided.
In this range, the fuel supply is interrupted to
protect the engine.

Everything under control
70
Engine oil thermometer
The engine oil temperature is between approx.
1607/706 and approx. 3407/1706 during
normal operation.
If the engine oil temperature is too high, a mes-
sage appears on the Control Display.
Fuel gage
Fuel tank capacity: approx. 18.5 US gallons/
70 liters, including the reserve capacity of
approx. 2.1 gallons/8 liters. You can find infor-
mation on refueling on page166.
If the tilt of the vehicle varies for a longer period,
when you are driving in mountainous areas, for
example, the indicator may fluctuate slightly.
After the reserve quantity has been reached, a
message appears for a short time on the Con-
trol Display; the remaining range is shown in the
computer. Below a range of approx. 30 miles/
50 km, the message remains on the Control
Display.
Refuel as soon as possible once your
cruising range falls below 30 miles/
50 km, as otherwise engine functions are not
ensured and damage can occur.<
Service requirements
The remaining distance to be driven and the
date for the next maintenance are briefly indi-
cated with the ignition key in position 2.
Your BMW Service Advisor will determine
your vehicle's current service require-
ments by reading out the data stored in the
master key.<
Additional information
You can view additional information on service
and maintenance procedures on the Control
Display.
Control Center, for principle details, refer to
page16.
1.Open the menu.
2.Select "Service" and press the controller.
3.Select "Service requirements" and press
the controller.
4.Select "Status" and press the controller.
The display shows a list of selected service and
maintenance procedures, as well as legally
mandated official inspections.