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247 Controls in detail
Driving systems
Distronic*
When activated, the Distronic adaptive
cruise control system increases driving
convenience afforded by the cruise control
during travel on expressways and other
major roads.
If the Distronic distance sensor detects
a slower moving vehicle directly ahead,
your vehicle speed will be reduced so
that you follow that vehicle at a preset
distance.
If there is no vehicle directly ahead of
you, Distronic will function in the same
way as cruise control (
page 252).
Warning!
G
Distronic adaptive cruise control is no sub-
stitute for active driving involvement. It does
not react to stationary objects, nor recog-
nize or predict the curvature and lane layout
or the movement of vehicles ahead.
Distronic can only apply a maximum of 20%
of the vehicle’s braking power.
It is the driver’s responsibility at all times to
be attentive to road, traffic and weather con-
ditions and to provide the steering, braking
and other driving inputs necessary to retain
control of the vehicle.Warning!
G
Distronic is a convenience system, its speed
adjustment reduction capability is intended
to make cruise control more effective and
usable when traffic speeds vary. It is not
however, intended to, nor does it, replace
the need for extreme care. The responsibili-
ty for the vehicle speed and the distance to
the vehicle ahead, including most impor-
tantly brake operation to assure safe stop-
ping distance, always rests with the driver.
Distronic cannot take street and traffic con-
ditions into account.
Warning!
G
Distronic requires familiarity with its opera-
tional characteristics. We strongly recom-
mend that you review the following
information carefully before operating the
system.iUSA only:
This device complies with Part 15 of
the FCC Rules. Operation is subject to
the following two conditions:
(1) This device may not cause harmful
interference, and
(2) this device must accept any inter-
ference received, including interfer-
ence that may cause undesired
operation.
Any unauthorized modification to this
device could void the user’s authority
to operate the equipment.
Page 249 of 521

248 Controls in detailDriving systems
iCanada only:
This device complies with RSS-210 of
Industry Canada. Operation is subject
to the following two conditions:
(1) This device may not cause interfer-
ence, and
(2) this device must accept any inter-
ference received, including interfer-
ence that may cause undesired
operation of the device.
Any unauthorized modification to this
device could void the user’s authority
to operate the equipment.Warning!
G
Distronic cannot take street and traffic con-
ditions into account. Only use Distronic if
the road, weather and traffic conditions
make it advisable to travel at a steady
speed.
Warning!
G
Use of Distronic can be dangerous on slip-
pery roads. Rapid changes in tire traction
can result in wheel spin and loss of control.
Distronic does not act upon adverse sight
distance conditions. Do not use Distronic
during conditions of fog and heavy rain,
snow or sleet.
Warning!
G
Distronic cannot take weather conditions
into account. Switch off Distronic or do not
turn it on if:
roads are slippery or covered with snow
or ice. The wheels could lose traction
while braking or accelerating, and the
vehicle could skid.
the sensor is dirty or visibility is
diminished due to snow, rain or fog. The
distance control could be impaired.
Always pay attention to traffic conditions
even while Distronic is switched on. Other-
wise, you may not be able to recognize
dangerous situations until it is too late and
could cause an accident resulting in person-
al or fatal injury to you or others.
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249 Controls in detail
Driving systems
Distronic displays in the speedometer
dial
1Set speed
If Distronic is activated, one or two seg-
ments come on around the set speed.
Warning!
G
Close attention to road and traffic condi-
tions is imperative at all times, regardless of
whether or not Distronic is activated.
Use of Distronic can be dangerous on wind-
ing roads or in heavy traffic because condi-
tions do not allow safe driving at a steady
speed.
Distronic will not react to stationary objects
in the roadway (e.g. a stopped vehicle in a
traffic jam or a disabled vehicle). Distronic
will also not respond to oncoming vehicles.
Switch off Distronic:
when changing from the left to the right
lane if vehicles are moving more slowly
in the left lane
when entering a turn lane or highway off
ramp
in complex driving situations, such as in
highway construction zones
In these situations, Distronic will continue to
maintain the set speed unless deactivated.
Distronic is designed and intended only to
maintain a set speed and keep a set dis-
tance from moving objects in front of it.Warning!
G
The “Resume” function should only be oper-
ated if the driver is fully aware of the previ-
ously set speed and wishes to resume this
particular preset speed.
iThe vehicle speed displayed on the
speedometer can briefly vary from the
speed setting on the Distronic system.
Page 251 of 521

250 Controls in detailDriving systems1Segments
If Distronic detects a vehicle directly
ahead, the segments (representing the
difference) from the speed of the vehicle
ahead to the set speed come on.
If Distronic calculates that there is a dan-
ger of collision:
The distance warning lampl in the
instrument cluster comes on red.
An intermittent warning sounds.
Immediately brake the vehicle to avoid
a collision.
Under no circumstances should the
driver await the intermittent warning
sound before braking. See the follow-
ing warning note.
The intermittent warning sound ceases
and the red distance warning
lampl goes out when the neces-
sary distance to the vehicle ahead is
again established.
Warning!
G
An intermittent warning sounds and the
distance warning lampl in the instru-
ment cluster is illuminated if the Distronic
system calculates that the distance to the
vehicle ahead and your vehicle’s current
speed indicate that Distronic will not be ca-
pable of slowing the vehicle sufficiently to
maintain the preset following distance,
which creates a danger of a collision.
Immediately brake the vehicle to increase
the distance to the vehicle in front of you.
The warning sound is intended as a final cau-
tion that you have not interceded with your
own braking inputs to avoid a potentially
dangerous situation. Do not wait for the op-
eration of the warning signal to intercede
with your own braking, as that will result in
potentially dangerous emergency braking
which will not always result in an impact be-
ing avoided.
Tailgating increases the risk of an accident.
Page 252 of 521
251 Controls in detail
Driving systems
Distronic menu in the control system
In the Distronic menu you can read the cur-
rent settings for Distronic. What appears in
the multifunction display depends on
whether Distronic and the distance warn-
ing function are turned on or off.
Press buttonè orÿ repeatedly
until you see one of the following dis-
plays.Distronic deactivated
When Distronic is deactivated you will see
the standard display of Distronic in the
multifunction display.
1Vehicle ahead, if detected
2Actual distance to vehicle ahead
3Preset distance threshold to vehicle
ahead
4Your vehicle
5Symbol for activated distance warning
function
Warning!
G
Distronic brakes your vehicle with a maxi-
mum deceleration of 6.5 ft / s
2 (2 m / s
2).
This corresponds to about 20% of the maxi-
mum deceleration ability of your vehicle.
Distronic brakes the vehicle in an effort to
restore the preset distance or to maintain
the speed.
Page 253 of 521

252 Controls in detailDriving systemsDistronic activated
If you turn Distronic on, you will see the set
speed in the multifunction display for
about 5 seconds. When Distronic is
activated, you will see the following display
in the multifunction display.
1Distronic activatedCruise control lever
The Distronic system is operated by means
of the cruise control lever.
The cruise control lever is the uppermost
lever on the left-hand side of the steering
column.
1Set current or higher speed
2Set current or lower speed
3Deactivate Distronic
4Resume at last set speedActivating Distronic
You can activate Distronic if
you are driving between 20 mph
(30km/h) and 110mph (180km/h)
the ESP
® is activated (
page 94)
If Distronic has not been activated after
pressing the cruise control lever you will
see the message
---
in the multifunction
display.
In the following cases you cannot activate
Distronic
up to 2 minutes after starting the en-
gine
when you brake
if you have set the parking brake
if the gear selector lever is in
positionP, R or N
if the ESP
® is switched off
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253 Controls in detail
Driving systems
Setting the current speed
Accelerate or decelerate to the desired
speed.
Briefly lift or depress the cruise control
lever.
The current speed is set.
Remove your foot from the accelerator
pedal.Setting a higher speed
Briefly tip the cruise control lever in di-
rection of arrow1 (
page 252) to in-
crease vehicle speed in increments of
5 mph (Canada: 10 km/h).
The new speed is set.
The stored speed is displayed in the
multifunction display for approximately
5 seconds (
page 252), and one or
two segments around the stored speed
come on in the speedometer
(
page 249).Setting a lower speed
Briefly tip the cruise control lever in di-
rection of arrow2 (
page 252) to de-
crease vehicle speed in increments of
5 mph (Canada: 10 km/h).
The new speed is set.
The stored speed is displayed in the
multifunction display for approximately
5 seconds (
page 252), and one or
two segments around the stored speed
come on in the speedometer
(
page 249).
iIf you do not take your foot off the
accelerator completely, the following
message will appear in the multifunc-
tion display: Distronic
overrideThe distance to a slower moving vehi-
cles in front of you will not be set. Your
vehicle speed will then be determined
only by the accelerator pedal position.
iDepressing the accelerator pedal does
not deactivate Distronic. After brief ac-
celeration (e.g. for passing), the cruise
control will resume the last speed set.
iWhen you use the cruise control lever
to decelerate, the brakes will be ap-
plied to support deceleration.
In addition, the transmission will auto-
matically downshift on long downhill
grades.
Page 255 of 521

254 Controls in detailDriving systemsFine adjustment in 1 mph
(Canada: 1 km/h) increments
Faster
Briefly tip the cruise control lever in di-
rection of arrow4 (
page 252).Setting to last stored speed
(“Resume” function)
Briefly tip the cruise control lever in di-
rection of arrow4 (
page 252).
Distronic is activated and set to the last
stored speed.
Remove your foot from the accelerator
pedal.Deactivating Distronic
There are several ways to deactivate the
Distronic system:
Briefly tip the cruise control lever in di-
rection of arrow3 (
page 252).
or
Step on the brake pedal.
Distronic will be deactivated. The last
speed set will be stored into memory.
Warning!
G
The speed stored in memory should only be
set again if prevailing road conditions per-
mit. Possible acceleration or deceleration
differences arising from returning to the pre-
set speed could cause an accident and/or
serious injury to you and others.
iThe following message will appear in
the multifunction display for approxi-
mately 5 seconds:Distronic offThe last stored speed is deleted when
you turn off the engine.