brake BMW 328I 2012 User Guide

Driving
66
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 high-
ways or other high-speed thoroughfares. Espe-
cially on longer trips, the system can reduce
fatigue and tension, while increasing your
enjoyment of driving. Please use it safely and
responsibly.
Within the limits of its capability, the system
automatically adapts the car's speed to that of a
slower vehicle in front of you. You can specify
the distance to be maintained from the vehicle
in front in four stages. For safety reasons, the
distance is speed-dependent. Based on your
selected distance setting, the system automat-
ically decreases the throttle setting and lightly
applies the brakes if necessary. The vehicle
brake lamps will automatically illuminate to sig-
nal 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 trans-
mission your vehicle is equipped with, to main-
tain the distance setting selected. If the vehicle
ahead speeds up or when the lane ahead
becomes clear, your vehicle will accelerate to
the speed you have selected by increasing the
throttle setting and shifting gears automatically
or by the driver as needed. Your selected speed
will be held when driving downhill, too.
Since this active cruise control system is a new
technology and operates differently from con-
ventional 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 System
limitations section beginning on page69.
Braking sensation
>If you step on the brake pedal while the sys-
tem is braking, pedal sensation will be
slightly different from the usual.
>Possible noises during automatic braking
are normal.
Manual transmission
You can shift gears while cruise control is acti-
vated. An indicator lamp notifies you that you
should shift gears when you drive for an
extended period at very high or very low engine
speeds, or the system is deactivated.
Range of applications
The minimum desired speed is 20 mph or
30 km/h, the maximum desired speed is
110mph or 180km/h.
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. Otherwise driving situations could result
that pose the risk of accidents.<

Driving
68 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.
Otherwise, an accident risk could result.<
Deactivating cruise control
Press the lever upward or downward, arrow3.
The displays in the speedometer disappear.
In addition, the system is automatically deacti-
vated:
>When you brake the vehicle
>When the speed is reduced to below
20 mph or 30 km/h due to a traffic situation
>When you switch gears very slowly or shift
to idle in cars with manual transmission
>When you select the automatic transmis-
sion's neutral position N
>When you activate the Dynamic Traction
Control DTC
>When you deactivate the Dynamic Stability
Control DSC
>When DSC or ABS is intervening
>When the system does not recognize any
objects for a longer period of time, e.g. on
infrequently traveled roads without a shoul-
der or guard rails, or if the radar sensor is
covered with dirt, refer to page69
>When you apply the parking brake
When the system is deactivated, you
must brake the vehicle yourself and/or
maneuver as necessary, otherwise there is a
risk of accident.<
Warning lamp
The warning lamp comes on when
active cruise control has been auto-
matically deactivated due to a driving
speed below 20 mph or 30 km/h, an application
of the parking brake or a DSC intervention. A
message appears on the Control Display.
Resuming stored desired speed and
distance
Briefly press the button, arrow 4.
The stored speed and distance are regained
and maintained.
In the following instances, the stored speed is
deleted and can no longer be resumed:
>When driving stability control systems are
intervening
>In cars with ma nua l trans mis sio n: when you
shift gears very slowly or shift to idle posi-
tion
>In cars with automatic transmission: when
you engage selector lever position N
>When the ignition is switched off
Displays in the instrument cluster
1Stored desired speed
2Shows yellow: vehicle detected ahead
Flashes in red: system cannot maintain dis-
tance; driver must brake the vehicle
Flashes in yellow: driving stability control
systems are intervening; cruise control is
deactivated
3Selected distance to vehicle ahead
The indicator lights up as soon as the sys-
tem is activated.

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4Selected desired speed is temporarily dis-
played
If --- mph or --- km/h temporarily appears
in the instrument cluster display, it is pos-
sible that the system prerequisites for operation
are currently not met. Calling up Check Control
messages, refer to page83.<
Warning lamps
The indicator2 flashes in red; a
signal sounds.
The system indicates that you
must brake and/or maneuver the
vehicle yourself. Active cruise con-
trol cannot automatically restore the distance to
the vehicle ahead.
This indicator does not release you from your
responsibility to adapt your desired speed and
driving style to prevailing driving conditions.
The indicator 2 flashes in yellow.
The prerequisites for operating
active cruise control are not met,
e.g. as a result of ABS or DSC
interventions. Active cruise control
is deactivated. You can reactivate the system, if
desired, by tapping or pulling the lever when road and traffic conditions permit. It is not pos-
sible to resume a stored speed.
Radar sensor
The sensor's ability to detect vehicles ahead
may be restricted as a result of heavy rain, dirt,
snow or ice. If necessary, clean the radar sensor
located in the front bumper, see arrow. Be sure
to use particular care when removing any layers
of snow or ice from the sensor.
When the radar sensor is not properly posi-
tioned, active cruise control cannot be activated
at all.
Malfunction
The warning lamp comes on when
the system has failed. A message
appears on the Control Display. You
can find more information starting on page82.
System limitations
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 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 motor-
cycles or bicycles. Be especially alert when
encountering any of these situations as the sys-
tem will neither automatically brake, nor provide

Driving
70 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 alert-
ness.<
Active cruise control is not and must not
be used as a collision avoidance/warning
system.<
If while your vehicle is actively following a vehi-
cle in front of you and the vehicle ahead speeds
up or the lane ahead becomes clear, then your
vehicle 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.
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, e.g.
when you reduce your desired speed sharply.
The system cannot stop your vehicle. It uses
only a portion of braking system capacity and
does not utilize the full capacity of the vehicle
braking system. Therefore, the system cannot
decrease your speed for large differences in
speed between your vehicle and the vehicle
ahead. Examples: when you approach a vehicle
traveling at a much lower speed than your own
speed such as approaching a toll booth or when
a much slower vehicle cuts in front of you at
close range.<
Active cruise control can only decelerate the
vehicle to approx. 20 mph or 30 km/h.
Swerving vehicles
When a vehicle moves from an adjacent lane
into your lane, active cruise control will not rec-
ognize this vehicle until it is fully in your lane
ahead of your vehicle.
When a vehicle ahead suddenly swerves
into your lane, the system may not be able
to maintain the selected distance automatically.
This also applies to great differences in speed
between you and vehicles ahead, e.g. when
quickly approaching a truck. There is a risk of
collision. Once the system has established that
a vehicle is indeed in front of you, it will indicate
that you must brake and/or maneuver the vehi-
cle yourself. Take action yourself, otherwise
there is a risk of an accident.<
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.

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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.
Your responsibility
Your actions have priority at all times. When you
press the accelerator pedal while driving with
active cruise control, the automatic braking
function will be temporarily interrupted. Once
you release the accelerator pedal, the desired
speed or the selected distance to the vehicle
ahead is achieved again.
Do not leave your foot on the accelerator
pedal and make sure that no objects such
as floor mats are lying on the accelerator pedal.
Otherwise the system may not be able to brake
the vehicle.<

Everything under control
78
Possible displays
1Button for selecting functions
2Service requirements
3Engine oil
4Roadworthiness test
*
5Microfilter
6Spark plugs7Front brake pads
8Rear brake pads
9Brake fluid
The sequence of displayed service items may
vary. The data for the next service appointment
is shown first.
Supplementary information
You can have further information on the scope
of maintenance displayed on the Control Dis-
play, refer to page16.
1.Open the start menu.
2.Press the controller to open the menu.
3.Select "Info sources" and press the control-
ler.
4.Select "Service" and press the controller.
5.If necessary, move the highlight marker to
the uppermost field. Turn the controller until "Service requirements" is selected and
press the controller.
6.If necessary, move the highlight marker to
the second field from the top. Turn the con-

Controls
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until "PDC" is selected and press the con-
troller.
6.Select "PDC display on" and press the con-
troller.
The PDC screen is activated.
The display is shown on the Control Display as
soon as PDC is activated.
System limitations
Even with PDC, final responsibility for
estimating the distance between the
vehicle and any obstructions always remains
with the driver. Even when sensors are pro-
vided, there is a blind spot in which objects can
no longer be detected. The system is also sub-
ject to the physical limits that apply to all forms
of ultrasonic measurement, such as those
encountered with trailer towbars and couplings,
thin and wedge-shaped objects, etc. Low
objects already indicated, such as a curb, may
enter the sensors' dead areas before a continu-
ous audible signal is given. Higher, protruding
objects, such as wall ledges, may not be detect-
able. Loud sound sources outside or inside the
car can drown out the PDC signal.<
Driving stability control
systems
Your BMW has a number of systems that help
to maintain the vehicle's stability even in
adverse driving conditions.
ABS Antilock Brake System
ABS prevents locking of the wheels during
braking. Safe steering response is maintained even during full braking. Active safety is thus
increased.
The ABS is operational every time you start the
engine. Braking safely, refer to page123.
Electronic brake-force distribution
The system controls the brake pressure in the
rear wheels to ensure stable braking behavior.
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 full brak-
ing. This system exploits all of the benefits pro-
vided by ABS.
Do not reduce the pressure on the brake for the
duration of the full braking application.
DSC Dynamic Stability Control
DSC prevents the driving wheels from losing
traction when you pull away from rest or accel-
erate. DSC also recognizes unstable driving
conditions, for example if the rear of the car is
about to swerve or if momentum is acting at an
angle past the front wheels. In these cases,
DSC helps the vehicle maintain a safe course
within physical limits by reducing engine output
and through braking actions at the individual
wheels.
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.<

Technology for driving comfort and safety
88
Deactivating DSC
Press the button for at least 3 seconds; the indi-
cator lamps for DSC in the instrument cluster
light up. Dynamic Traction Control DTC and
DSC have been simultaneously deactivated.
Stabilizing and drive-output promoting actions
are no longer executed.
To increase vehicle stability, activate DSC again
as soon as possible.
Activating DSC
Press the button again; the indicator lamps in
the instrument cluster go out.
For better control
If the indicator lamp flashes:
DSC controls the drive forces and
brake forces.
If the indicator lamps are on:
DSC is deactivated.
DTC Dynamic Traction Control
DTC is a version of DSC in which the drive out-
put is optimized for particular road conditions,
e.g. unplowed snow-covered roads. The sys-
tem assures the maximal drive output, but with
reduced driving stability. It is therefore neces-
sary to drive with appropriate caution.
You may find it useful to briefly activate DTC
under the following special circumstances:
>When driving uphill on snow-covered roads,
in slush or on unplowed, snow-covered
roads
>When rocking a stuck vehicle free or start-
ing off in deep snow or on loose ground>When driving with snow chains
Activating DTC
Press the button; the indicator lamps for DTC in
the instrument cluster come on.
For better control
If the indicator lamp flashes:
DTC controls the drive forces and
brake forces.
If the indicator lamps are on:
DTC has been activated.
Deactivating DTC
Press the button again; the DTC indicator
lamps in the instrument cluster go out.
xDrive
xDrive is your BMW's four-wheel-drive system.
The combined efforts of xDrive and DSC help to
further optimize traction and driving dynamics.
The xDrive four-wheel-drive system distributes
driving power variably to the front and rear axles
depending on the driving situation and road
conditions.
Hill Descent Control
HDC is a downhill driving assistant that reduces
your speed on steep downhill gradients and
makes it even easier to control your BMW's
handling under these conditions. The vehicle
then moves slightly faster than double walking
speed without the driver needing to intervene.
HDC can be activated as long as you are driving
under approx. 20 mph or 35 km/h. When driving
downhill at a speed of under approx. 20 mph or

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35 km/h, the vehicle's speed is automatically
reduced to slightly more than double walking
speed and maintained.
Increasing or decreasing speed
By accelerating or braking you can change the
speed within a range from approx. 3 to 15 mph,
approx. 5 to 25 km/h.
You can specify a target speed within the same
range using the cruise control lever.
1To increase speed
2To decrease speed
Activating HDC
Press the button; the indicator lamp lights up.
The indicator lamp flashes when the vehicle is
being braked automatically.
Deactivating HDC
Press the button again; the indicator lamp goes
out.
HDC is automatically deactivated in the follow-
ing situations:
>at speeds above approx. 40 mph or
60 km/h
>after switching off the ignition.
Using HDC
In cars with manual transmission:
Use HDC in lower gears and in reverse gear.
With automatic transmission:
You can use HDC in any drive position.
Displays in the instrument cluster
1Display for target speed
2HDC display
Malfunction
The HDC display disappears during HDC oper-
ation, or does not appear:
HDC is temporarily unavailable due to exces-
sive brake temperature, or DSC has failed.
Drive-off assistant
The drive-off assistant enables you to drive off
smoothly on uphill gradients. It is not necessary
to use the parking brake for this.
1.Hold the car in place by depressing the
brake.
2.Release the brake and drive off without
delay.
The drive-off assistant holds the car in
place for approx. 2 seconds after the
brake is released. Depending on vehicle load,
the car may roll backwards a little during this
time span. Drive off without delay after releas-
ing the brake. Otherwise, the drive-off assistant
will no longer hold the car in place after approx.
2 seconds and the car will start to roll back-
wards.<

Technology for driving comfort and safety
94 an added safety feature, your vehicle has been
equipped with a tire pressure monitoring sys-
tem, TPMS, that illuminates a low tire pressure
telltale when one or more of your tires are signif-
icantly under-inflated. Accordingly, when the
low tire pressure telltale illuminates, you should
stop and check your tires as soon as possible,
and inflate them to the proper pressure. Driving
on a significantly underinflated tire causes the
tire to overheat and can lead to tire failure.
Underinflation also reduces fuel efficiency and
tire tread life, and may affect the vehicle’s han-
dling and stopping ability. Please note that the
TPMS is not a substitute for proper tire mainte-
nance, and it is the driver’s responsibility to
maintain correct tire pressure, even if underin-
flation has not reached the level at which the
TPMS low tire pressure telltale illuminates.
The TPMS malfunction indicator is combined
with the low tire pressure telltale. When the sys-
tem detects a malfunction, the telltale will flash
for approximately one minute and then remain
continuously lit. This sequence will continue
upon subsequent vehicle startups as long as
the malfunction exists. When the malfunction
indicator is illuminated, the system may not be
able to detect or signal low tire pressure as
intended. TPMS malfunctions may occur for a
variety of reasons, including the installation of
replacement or alternate tires or wheels on the
vehicle that prevent the TPMS from functioning
properly. Always check the TPMS malfunction
telltale after replacing one or more tires or
wheels on your vehicle to ensure that the
replacement or alternate tires and wheels allow
the TPMS to continue to function properly.
Active steering*
The concept
Active steering varies the turning angle of the
front wheels in relation to steering wheel move-
ments. It also varies the steering force required
to turn the wheels depending on the speed at
which you are driving.
When you are driving in the low road-speed
range, e.g. in a town or when parking, the steer-ing angle increases, i.e. the steering becomes
very direct, and less effort is required to turn the
wheels. In the higher speed range, on the other
hand, the steering angle 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 tar-
geted corrections to the steering angle pro-
vided by the driver and thus stabilize the vehicle
before the driver intervenes. This stabilizing
intervention is simultaneously deactivated
when DSC is switched off, refer to page88.
Malfunction
The warning lamps come on. Active
steering is no longer operational. At
low speeds, greater steering wheel
movements are required, whereas at
higher speeds the vehicle reacts more sensi-
tively to steering wheel movements. The stabil-
ity-enhancing feature may also be deactivated.
Drive cautiously and think well ahead. Have the
system checked.
If the warning lamp lights up during the first
engine starting following a power supply inter-
ruption, the system must be activated by being
initialized.
Brake Force Display
On the left: normal braking
On the right: sharp braking