
Controls
 63Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
Acceleration assistant
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, otherwise components will wear 
prematurely.<
1.Activate the Dynamic Driving Control.
2.Deactivate DSC, refer to page87.
3.Quickly press accelerator pedal all the way 
down: kick-down. The ideal starting-off 
engine speed is set.
To maintain the vehicle stability, reacti-
vate DSC afterward.<
Automatic transmission with 
Steptronic*
In addition to fully automatic operation, you can 
also manually shift with the Steptronic, refer to 
page64.
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 selector lever positions
>Only move the selector lever from posi-
tion P when the engine is running: interlock.
>With the vehicle stopped, press the brake 
before shifting out of P or N, otherwise the 
selector lever is blocked: shiftlock.
To prevent the vehicle from creeping 
after you select a driving position, 
maintain pressure on the brake pedal until 
you are ready to start.<
A lock prevents accidentally shifting into the 
selector lever positions R and P. To cancel the 
lock, press the button on the front of the selec-
tor lever, refer to arrow.
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
Can, for example, be engaged in automatic car 
washes. The vehicle can roll.
D Drive, automatic position
Position for normal vehicle operation. All for-
ward gears are available.
Under normal operating conditions, the fuel 
consumption is lowest when driving in posi-
tion D. 

Controls
 67Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
Otherwise you could loose control of the vehi-
cle and cause an accident.<
One lever for all functions
1Maintaining speed, storing speed, and 
accelerating
2Maintaining speed, storing speed, and 
decelerating
3Interrupting cruise control
4Resuming stored speed
Maintaining speed, storing speed, 
and accelerating
Press lever to resistance point, arrow 1: 
The speed currently being driven is maintained 
and stored. The display1 in the speedometer, 
see below, indicates this regulated speed. 
Every time you press the lever, the vehicle's 
speed increases by roughly 1 mph/1 km/h.
Press lever to resistance point for a longer time: 
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: 
increase speed by 5 mph/10 km/h.
If, on a downhill grade, the engine's braking 
effect is not sufficient, the controlled speed can 
be exceeded. Speed can drop on uphill grades if 
the engine output is insufficient.
Maintaining speed, storing speed, and 
decelerating
Pull the lever, arrow2: 
Functions are the same as1, only the vehicle 
speed is reduced.
Interrupting cruise control
Press the lever up or down, arrow3.
In addition, cruise control is automatically deac-
tivated:
>When the brakes are applied
>When the clutch pedal is depressed or the 
automatic transmission/SMG is shifted into 
the N position
>When the DSC comes on
Resuming stored speed
Press button4: 
The stored speed is resumed and maintained.
Deactivating system
When the ignition is switched off, the system is 
deactivated and the stored speed is deleted.
Displays in instrument cluster
1Stored desired speed
2Selected desired speed appears briefly
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.  

Driving
68 Especially 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 you 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. You can vary the distance, which 
is additionally speed-dependent. Based on 
your selected distance setting, the system 
automatically decreases the throttle setting and 
lightly applies the brakes if necessary. The vehi-
cle brake lamps will automatically illuminate to 
signal a following driver to take action. In addi-
tion, 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 vehicle will acceler-
ate to the speed you have selected by increas-
ing the throttle setting and shifting gears auto-
matically or by the driver as needed. Your 
selected speed will be held when driving down-
hill, too.
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 begin-
ning on page71.<
Professional navigation system*
If a navigation DVD is in the drive, refer to 
page132, the system adjusts the accelerating 
and braking behavior of the vehicle to the road 
you are driving on.
To ensure that the system is informed of 
the current course of the road, always use 
the latest navigation DVD if possible.<
When the vehicle position is unknown, e.g. 
when you leave the map area, this influence of 
the navigation system is not available.
Brake pedal feel
>When the system brakes and you also 
depress the brake pedal, a somewhat differ-
ent braking feeling results.
>Any noises produced during automatic 
braking are normal.
Manual transmission
You can shift with the cruise control activated. 
Shifting information is provided or the system 
deactivates itself if you drive at very high or very 
low engine speeds for a longer period.
SMG
In the Sequential mode, shifting information is 
provided or the system deactivates itself if you 
drive at very high engine speeds for a longer 
period.
In the Drive mode the SMG acts similarly to an 
automatic transmission in the D position.
Operating active cruise control
1Store and increase desired speed
2Store and decrease desired speed 

Controls
 69Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
3Deactivate system, refer to page70
4Resume stored desired speed and dis-
tance, refer to page70
5Select distance to vehicle driving ahead, 
refer to page69
Maintaining current speed
Briefly press lever, arrow1, or briefly pull lever, 
arrow2, at a driving speed of more than approx. 
20 mph or 30 km/h.
The speed currently being driven is stored and 
maintained. It is indicated on the speedometer 
and briefly in the instrument cluster.
Selecting desired speed
Adjust your desired speed to the traffic 
conditions and remain ready to brake at 
all times, otherwise accidents can occur.<
The desired speed can drop on uphill grades if 
the engine output is insufficient.
Increasing in steps
Briefly press the lever repeatedly up to the 
resistance point or beyond, arrow1, until the 
desired speed is displayed.
>Each time the lever is briefly pressed up to 
the resistance point, the desired speed 
increases by approx. 1 mph or 1 km/h.
>Each time the lever is briefly pressed 
beyond the resistance point, the desired 
speed is increased by a maximum of 5 mph 
or 10 km/h until the maximum speed of 
110mph or 180km/h is reached.
The speed then displayed is stored and 
reached on a clear road.
Decreasing in steps
Repeatedly pull the lever up to the resistance 
point or beyond, arrow2, until the desired 
speed is displayed.
>Each time the lever is pulled up to the resis-
tance point, the desired speed decreases 
by approx. 1 mph or 1 km/h.
>Each time the lever is pulled beyond the 
resistance point, the desired speed is 
decreased by a maximum of 5 mph or 
10 km/h until the minimum speed of 
20 mph or 30 km/h is reached.
The speed then displayed is stored and 
reached on a clear road.
Select distance
>Rotary switch downward: 
Increase distance.
>Rotary switch upward: 
Decrease distance.
The selected distance is displayed in the instru-
ment cluster.
Distance 1
Distance 2  

Driving
70 Use good judgment to select the appro-
priate following distance given road con-
ditions, traffic, applicable laws and driving rec-
ommendations for a safe following distance.<
Deactivate system
Press the lever up or down. The displays in the 
instrument cluster disappear.
You also deactivate the system when you 
brake, shift very slowly or into neutral, or 
engage the selector lever position N. In addi-
tion, the system is deactivated automatically:
>When you activate DTC Dynamic Traction 
Control 
>When you deactivate DSC Dynamic Stabil-
ity Control 
>When the system does not recognize any 
objects for a longer time, e. g. on infre-
quently traveled roads without a shoulder or 
guard rails, or if the radar sensor is covered 
with dirt, refer to page71
>When the speed is reduced to below 
20 mph/30 km/h due to a traffic situation
The system deactivates automatically 
when the speed is set to below 20 mph/
30 km/h. A signal sounds and a message 
appears on the Control Display. The active intervention of the driver is required, otherwise 
accidents can occur.<
Resume stored desired speed and 
distance
Press button 4. 
The displays appear in the instrument cluster.
When you switch off the ignition, the stored 
desired speed is deleted.
Displays in instrument cluster
1Stored desired speed
2Lights up yellow: vehicle driving ahead is 
detected
Flashes red, a signal sounds: the system 
cannot establish the distance, apply the 
brakes yourself
Flashes yellow: driving stability control sys-
tems intervene, the active cruise control is 
deactivated
3Selected distance to vehicle driving ahead: 
lights up as soon as the system is activated
4Selected desired speed appears briefly
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 Con-
trol messages, refer to page79.< Distance 3 
This distance is set when the sys-
tem is used for the first time after 
starting the engine.
Distance 4 

Controls
 71Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
Warning lamps
The display2 flashes red and a sig-
nal sounds. 
The system requests that you 
intervene by braking or with an 
evasive maneuver. The active 
cruise control cannot automatically restore the 
distance to the vehicle driving ahead. 
However, this display cannot relieve the driver 
of the responsibility for adjusting the desired 
speed and driving style to the traffic conditions.
The display2 flashes yellow. 
Automatic intervention by ABS or 
DSC. The active cruise control 
intervenes by braking until you 
take over actively.
Radar sensor
Heavy rain, dirt, snow or ice can restrict the 
detection of vehicles driving ahead. If neces-
sary, clean the front radar sensor under the 
bumper. Exercise particular care when remov-
ing snow and ice.
If the sensor is not aligned properly, the active 
cruise control cannot be activated.
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 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  

Driving
72 system will neither automatically brake, nor pro-
vide 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.<
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.
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.<
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.
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.
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  

Controls
 73Reference
At a glance
Driving tips
Communications
Navigation
Entertainment
Mobility
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 the system activated, resting your 
foot on the accelerator pedal will cause the sys-
tem not to brake even if necessary. Be certain 
that floor mats or other objects on the vehicle 
floor do not interfere with movement of the 
accelerator 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, 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 due to large differences in 
speed between your vehicle and the vehicle 
ahead. Example: 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.<