Distronic displays in the speedometer
When the Distronic is activated, one or two
cruise control speed segments come on
around set speed :.
The vehicle speed displayed on the
speedometer can briefly vary from the speed
setting on the Distronic system.
When the Distronic detects a vehicle directly
ahead, the cruise control speed
segments ; appear in the speedometer.
These segments represent the difference
between the set speed of your vehicle : and
the speed of the preceding vehicle =.
If the Distronic calculates that there is a
danger of collision, the distance warning lamp
· in the instrument cluster comes on and
an intermittent warning sounds.
XImmediately apply the brakes to avoid a
collision.
Under no circumstances should the driver
await the intermittent warning sound
before braking.
The intermittent warning sound ceases and
the distance warning lamp · goes out
when the necessary distance to the vehicle
ahead is established again.
GWarning!
An intermittent warning sounds and the
distance warning lamp · in the instrument
cluster is illuminated if the Distronic system
calculates that the distance to the vehicle
ahead and your vehicle’s current speed
indicate that the Distronic will not be capable
of slowing the vehicle sufficiently to maintain
the preset following distance, which creates
a danger of a collision.
Immediately brake the vehicle to increase
your distance to the preceding vehicle. The
warning sound is intended as a final caution
in which you should intercede with your own
braking inputs to avoid a potentially
dangerous situation. Do not wait for the
operation of the warning signal to intercede
with your own braking. This will result in
potentially dangerous emergency braking
which will not always result in an impact being
avoided.
Tailgating increases the risk of an accident.
GWarning!
The Distronic brakes your vehicle with a
maximum deceleration of 6.5 ft/s2 (2 m/s2).
This corresponds to approximately 20% of the
maximum deceleration of your vehicle.
You must also apply the brakes yourself to
avoid a collision. The Distronic brakes the
vehicle in an effort to restore the preset
distance or to maintain the set speed. The
brake pedal is automatically applied as this
happens which results in the brake pedal
moving
Keep driver’s foot area clear at all times,
including the area under the brake pedal.
Objects stored in this area may impair pedal
movement which could interfere with the
braking ability of the Distronic system.
Do not place your foot under the brake pedal
– your foot could become caught.
146Driving systemsControls in detail
164_AKB; 7; 31, en-USd2ureepe,Version: 2.11.8.12009-09-11T12:07:36+02:00 - Seite 146
Distronic menu in the control system
Use the DISTRONIC menu to display the
current settings for your Distronic system.
The information shown in the multifunction
display depends on whether the Distronic
system and/or the distance warning function
are activated or deactivated.
iTo activate or deactivate the Distronic
system, see (Y page 147) or see
(Y page 149).
To activate or deactivate the Distance
warning function, see (Y page 137).
XPress button V or U repeatedly until
one of the following two displays appears
in the multifunction display.
Distronic deactivated
When the Distronic is deactivated, you will
see the standard Distronic display in the
multifunction display.
:Preceding vehicle, if detected;Actual distance to the preceding vehicle=Preset distance threshold to the
preceding vehicle
?Your vehicle
Distronic activated
When the Distronic is activated :, you will
see the set speed ; in the multifunction
display for approximately 5 seconds. The
following display appears in the multifunction
display.
After approximately 5 seconds the currently
set speed ; appears in the status indicator
of the multifunction display:
DTR XXX Miles
Cruise control lever
The Distronic system is operated by means of
the cruise control lever.
:Setting current or higher speed;Setting current or lower speed=Deactivating the Distronic?Activating the Distronic or resuming to
the last set speed
Activating Distronic
You can activate the Distronic when the
vehicle speed is between 20 mph (30 km/h)
and 110 mph (180 km/h).
When the Distronic is activated, one or two
cruise control speed segments around the set
speed in the speedometer dial are
illuminated. The multifunction display will
show a message such as
DISTRONIC 55 MPH
(Canada: DISTRONIC 90 km/h).
Driving systems147Controls in detail164_AKB; 7; 31, en-USd2ureepe,Version: 2.11.8.12009-09-11T12:07:36+02:00 - Seite 147Z
After approximately 5 seconds the currently
set speed appears in the status indicator of
the multifunction display:
R USA only: e.g. DTR 55 Miles
R Canada only: e.g. DTR 90 km/h
If the Distronic is not activated after the
cruise control lever is pulled in direction of
arrow ? (Y page 147), you will see the
message DISTRONIC Off in the
multifunction display.
In the following cases you cannot activate the
Distronic:
R up to 2 minutes after starting the engine
R when you brake
R when you have engaged the parking brake
R when the automatic transmission is in park
position P, reverse gear R, or neutral
position N
R when the ESP ®
is switched off or has
switched off due to a malfunction
The vehicle speed displayed on the
speedometer can briefly vary from the speed
setting on the Distronic system.
Setting the current speedXAccelerate or decelerate to the desired
speed.XBriefly lift the cruise control lever in
direction of arrow : or depress in
direction of arrow ; (Y page 147).XRemove your foot from the accelerator
pedal.
i If you do not take your foot off of the
accelerator pedal and continue to
accelerate past the set speed, the following
message will appear in the multifunction
display:
DISTRONIC Override
The distance to a slower moving vehicle in
front of you will not be set. Your vehicle
speed will then be determined only by the
accelerator pedal position.
Changing the set speedGWarning!
Keep in mind that it may take a brief moment
until the vehicle has made the necessary
adjustments.
Increase or decrease the set vehicle speed to
a value that the prevailing road conditions and
legal speed limits permit. Otherwise, sudden
and unexpected acceleration or deceleration
of the vehicle could cause an accident and/
or serious injury to you and others.
You can increase or decrease the set speed
in 1 mph (Canada: 1 km/h) increments or in
5 mph (Canada: 10 km/h) increments.
When you use the cruise control lever to
decelerate, the brake system will brake the
vehicle automatically if the engine’s braking
power does not brake the vehicle sufficiently.
Adjustment in 1 mph (Canada:
1 km/h) increments
i The set speed value is increased or
decreased in 1 mph (Canada: 1 km/h)
increments each time you lift or press the
cruise control lever up or down to the
resistance point.
XIncreasing: Briefly lift the cruise control
lever up to the resistance point in direction
of arrow : (Y page 147).XDecreasing: Briefly press the cruise
control lever down to the resistance point
in direction of arrow ; (Y page 147).XRelease the cruise control lever.
The new speed is set and the vehicle will
accelerate or decelerate.
Adjustment in 5 mph (Canada:
10 km/h) increments
i The set speed value is increased or
decreased in 5 mph (Canada: 10 km/h)
increments each time you lift or press the
cruise control lever up or down past the
resistance point.
148Driving systemsControls in detail
164_AKB; 7; 31, en-USd2ureepe,Version: 2.11.8.12009-09-11T12:07:36+02:00 - Seite 148
XIncreasing: Briefly lift the cruise control
lever up past the resistance point in
direction of arrow : (Y page 147).XDecreasing: Briefly press the cruise
control lever down past the resistance
point in direction of arrow ;
( Y page 147).XRelease the cruise control lever.
The new speed is set and the vehicle will
accelerate or decelerate. Keep in mind that
it may take a brief moment until the vehicle
has reached the set speed.
Setting stored speed (Resume function)
GWarning!
The set speed stored in memory should only
be set again if prevailing road conditions and
legal speed limits permit. Possible
acceleration or deceleration differences
arising from returning to the preset speed
could cause an accident and/or serious injury
to you and others.
XBriefly pull the cruise control lever in
direction of arrow ? (Y page 147).
If no speed is stored, the current speed is
set and stored.XRemove your foot from the accelerator
pedal.
Deactivating Distronic
XDepress the brake pedal.
or
XBriefly push the cruise control lever in
direction of arrow = (Y page 147).
The cruise control speed segments in the
speedometer dial will go out and the
following message appears briefly in the
multifunction display: DISTRONIC Off
The last set speed is stored for later use.
The last stored speed is deleted from memory
when the engine is turned off.
The Distronic switches off automatically
when you depress the brake pedal or you
engage the parking brake. In this case, the
cruise control speed segments in the
speedometer dial will go out.
The Distronic also switches off automatically
when
R the vehicle speed falls below 20 mph
(30 km/h)
R the ESP ®
is in operation
R the ESP ®
is switched off with the ESP ®
switch
R the ESP ®
has switched off due to a
malfunction
R you shift the automatic transmission into
neutral position N while driving
The cruise control speed segments in the
speedometer dial goes out and an acoustic
warning will sound. Observe additional
messages in the multifunction display that
may appear.GWarning!
Distronic switches off and releases the brakes
when the vehicle decelerates below the
minimum speed of 20 mph (30 km/h) by
operation of the system. At that time the
driver must apply the brakes in order to
reduce vehicle speed further or bring it to a
stop.
Depressing the accelerator pedal does not
deactivate the Distronic. After a brief
acceleration (e.g. for passing), the Distronic
will resume the last set speed.
Setting the following distance in
Distronic
You can set the specified following distance
for Distronic by varying the time setting
between 1.0 and 2.0 seconds. Using this time
setting and the current speed of your vehicle,
Distronic calculates and sets the required
following distance to the preceding vehicle.
The set distance will be shown in the
multifunction display.
Driving systems149Controls in detail164_AKB; 7; 31, en-USd2ureepe,Version: 2.11.8.12009-09-11T12:07:36+02:00 - Seite 149Z
GWarning!
It is up to the driver to exercise discretion to
select the appropriate setting given road
conditions, traffic, driver’s preferred driving
style and applicable laws and driving
recommendations for safe following distance.
XIncreasing distance: Turn distance
setting switch : in direction of arrow =.
Increasing the distance setting tells
Distronic to maintain a greater following
distance to the preceding vehicle.
XDecreasing distance: Turn distance
setting switch : in direction of arrow ;.
Decreasing the distance setting tells
Distronic to maintain a shorter following
distance to the preceding vehicle.
Driving with Distronic
This section describes a number of driving
situations where special precaution is
required on the part of the driver. Be prepared
to brake in such situations. Braking will
deactivate the Distronic system.
GWarning!
The Distronic works to maintain the speed
selected by the driver unless a moving
obstacle proceeding directly ahead of it in the
same travel direction is detected (e.g.
following another vehicle ahead of you at your
set distance).
This means that:
RYour vehicle can pass another vehicle after
you have changed lanes.
RWhile in a sharp turn or if the preceding
vehicle is in a sharp turn, the Distronic
could lose sight of the preceding vehicle.
Your vehicle could then accelerate to the
previously selected speed.
The Distronic regulates only the distance
between your vehicle and those directly
ahead of it, but does not register stationary
objects in the road, e.g.:
Ra stopped vehicle in a traffic jam
Ra disabled vehicle
Ran oncoming vehicle
The driver must always be alert, observe all
traffic and intercede as required by means of
steering or braking the vehicle.
GWarning!
The Distronic should not be used in snowy or
icy road conditions.
The most likely cause for a malfunctioning
system is a dirty Distronic system sensor
cover (located in the hood grille), especially
at times of snow and ice or heavy rain.
In such a case, the Distronic will switch off,
and the message DISTRONIC Currently
Unavailable – See Operator’s Manual
appears in the multifunction display.
For cleaning and care of the Distronic system
sensor cover, see (Y page 263).
iIf the message DISTRONIC Available
Again appears during driving, the dirt (e.g.
slush) has dissolved; the Distronic works
again, if you reactivate it (Y page 147).
150Driving systemsControls in detail
164_AKB; 7; 31, en-USd2ureepe,Version: 2.11.8.12009-09-11T12:07:36+02:00 - Seite 150
Turns and bends
In turns or bends, the Distronic may not
detect a moving vehicle in front, or it may
detect one too soon. This may cause your
vehicle to brake late or unexpectedly.
Offset driving
A vehicle traveling in your lane but offset from
your direct line of travel may not be detected
by the Distronic. There will be insufficient
distance to the preceding vehicle.
Lane changing
The Distronic has not yet detected the vehicle
changing lanes. There will be insufficient
distance to the lane-changing vehicle.
Narrow vehicles
Because of their narrow profile, the vehicles
traveling near the outer edges of the lane
have not yet been detected by the Distronic.
There will be insufficient distance to the
preceding vehicles.
Distance warning function
This function warns you at a vehicle speed of
above approximately 20 mph (30 km/h) in
the following cases:
RAt the current speed, the distance between
your vehicle and the preceding vehicle is
too low for several seconds. The distance
warning lamp · in the instrument
cluster comes on.
RYou are gaining on a preceding vehicle
rapidly. An intermittent warning sounds
and the distance warning lamp · in the
instrument cluster comes on.
If these warnings are issued, you must apply
the brakes to maintain a safe distance and
avoid a collision with the preceding vehicle.
When depressing the brake pedal, the
warning sound ceases. The warning sound
will also cease when the distance to the
preceding vehicle is sufficient again without
applying the brakes. In this case, the distance
warning lamp · will also go out.
Driving systems151Controls in detail164_AKB; 7; 31, en-USd2ureepe,Version: 2.11.8.12009-09-11T12:07:36+02:00 - Seite 151Z
GWarning!
If the distance warning lamp · in the
instrument cluster comes on while driving
and/or an intermittent warning sounds,
immediate attention on the part of the driver
is required. As required by the traffic
situation, apply the brakes and navigate
around a possible obstacle. However, do not
drive by relying on the distance warning
function, as this will result in an emergency
braking application. This will not always
enable you to avoid a collision, especially
when traveling on varying road surface
conditions and with varying driver reaction.
Complex driving situations are not always
fully recognized by the distance warning
function. This could result in wrong or missing
distance warnings.
XActivating/deactivating: Activate or
deactivate the distance warning function in
the control system ( Y page 137).
When activated, the distance warning
function indicator Ä appears in the
multifunction display.
Hill-start assist system
GWarning!
The hill-start assist system is not designed to
function as a parking brake. It does not
prevent the vehicle from moving when parked
on an incline.
Always engage the parking brake in addition
to shifting the automatic transmission into
park position P.
On uphill grades, the hill-start assist system
maintains the pressure in the brake system
for approximately 1 second after you have
released the brake pedal. Therefore, you can
start off smoothly without the vehicle moving
immediately after releasing the brake pedal.
XDepress the brake pedal.XShift the automatic transmission into drive
position D or reverse gear R.XRelease the brake pedal.XCarefully depress the accelerator pedal.
The hill-start assist system is inactive
R when starting off on a level road or downhill
grades
R with the automatic transmission in neutral
position N
R with the parking brake engaged
R if the ESP ®
has switched off due to a
malfunction
Downhill Speed Regulation (DSR)
For information on off-road driving, see “Off-
road driving” ( Y page 248).
The DSR is an aid for driving downhill. The
DSR regulates your vehicle’s speed when
driving downhill to the value set in the control
system ( Y page 138). The steeper the
downhill gradient is, the greater the brake
application. On flat road surfaces, the DSR
brakes only slightly or not at all.
GWarning!
The Downhill Speed Regulation (DSR) is a
convenience system designed to assist the
driver during vehicle operation. The system
must be set to be appropriate for the
topographical and weather conditions
encountered which can change quickly. The
driver is and must remain at all times
responsible for the vehicle speed and for safe
brake operation.
Depending on the programmed speed, actual
vehicle speed and gradient, switching on the
DSR while driving can cause the vehicle to
slow down rapidly and you may hear a sound
which is caused by the activation of the
vehicle’s brake system through the DSR.
Sudden and unexpected deceleration can
result in loss of vehicle control, causing an
accident and/or serious personal injury to
you and others. Do not switch on the DSR in
152Driving systemsControls in detail
164_AKB; 7; 31, en-USd2ureepe,Version: 2.11.8.12009-09-11T12:07:36+02:00 - Seite 152
a circumstance where rapid deceleration
could result in a loss of vehicle control.
The DSR regulates the vehicle’s speed in
automatic transmission positions D, or R.
iIn addition, make use of the engine’s
braking effect by shifting the automatic
transmission into a lower gear.
You can drive slower or faster than the set
speed at any time by braking the vehicle or
depressing the accelerator pedal.
iWhenever the DSR is switched on, the
DSR will use the programmed default
speed to regulate the vehicle’s speed. The
default speed programmed at the factory is
4 mph (Canada: 6 km/h). The default speed
can be reprogrammed using the control
system (Y page 138). The next time the
DSR is switched on, the DSR will use the
newly programmed default speed to
regulate the vehicle’s speed.
Once the DSR is switched on, you can
adjust the set speed using the cruise
control lever (Y page 142). Keep in mind
that adjusting the set speed using the
cruise control lever with the DSR switched
on will not change the programmed default
speed. If the DSR is switched off and then
switched on again, the DSR will use the
programmed default speed.
Depending on the road surface and level of
downhill grade, the DSR may not be able to
maintain the set speed. To maintain the set
speed, apply the brakes if necessary.
Switching the DSR on/offGWarning!
If the accelerator pedal is depressed while the
Downhill Speed Regulation (DSR) is activated,
the vehicle can drive faster than the
programmed set speed. You should therefore
drive downhill with particular caution as it
could otherwise lead to an accident and/or
serious injury to you or others. Keep in mind
that as soon as you remove your foot from the
accelerator pedal with the DSR switched on,
the DSR will start regulating the vehicle’s
speed including use of brakes if required.
Depending on the programmed set speed,
actual vehicle speed and gradient, the DSR
can cause the vehicle to slow down rapidly.
Sudden and unexpected deceleration can
result in loss of vehicle control, causing an
accident and/or serious personal injury to
you and others.
Switching on the DSR
The DSR can only be switched on if the vehicle
speed is below 20 mph (Canada: 30 km/h).
XPress DSR switch :.
Indicator lamp ; comes on.
The message DSR and the set speed appear
in the multifunction display.
Driving systems153Controls in detail164_AKB; 7; 31, en-USd2ureepe,Version: 2.11.8.12009-09-11T12:07:36+02:00 - Seite 153Z