MERCEDES-BENZ S-Class 2008 W221 Comand Manual
Page 451 of 801
450 Controls in detailDriving systems
Release the cruise control lever.
The vehicle set speed increases in in-
crements 5 mph (Canada: 10 km/h).
Setting a lower speed
You can reduce the set speed in two ways.Adjustment in 1 mph (Canada: 1 km/h) 
increments
Briefly press the cruise control lever 
down to the resistance point in direc-
tion of arrow2 (
page 447).
Release the cruise control lever.
The vehicle set speed decreases in in-
crements 1 mph (Canada: 1 km/h).
Adjustment in 5 mph 
(Canada: 10 km/h) increments
Briefly press the cruise control lever 
down past the resistance point in 
direction of arrow2 (
page 447).
Release the cruise control lever.
The vehicle set speed decreases in in-
crements 5 mph (Canada: 10 km/h).
Setting to last stored speed 
(“Resume” function)
i
The new speed is set and the vehicle will ac-
celerate. Keep in mind that it may take a brief 
moment until the vehicle has reached the set 
speed.Warning!
G
If you decrease the set speed, keep in mind 
that it may take a brief moment until the ve-
hicle has made the necessary adjustments.
Decelerate the set speed to a value that the 
prevailing road conditions and legal speed 
limits permit. Otherwise, sudden and unex-
pected deceleration of the vehicle could 
cause an accident and/or serious injury to 
you and others.
i
When you use the cruise control lever to de-
celerate, the brake system will automatically 
brake the vehicle if the engine’s braking power 
does not brake the vehicle sufficiently.
i
The set speed value is decreased in 1 mph 
(Canada: 1 km/h) increments each time you 
press the cruise control lever down to the resis-
tance point.
i
The set speed value is decreased in 5 mph 
(Canada: 10 km/h) increments each time you 
press the cruise control lever down past the re-
sistance point.
i
The new speed is set and the vehicle will de-
celerate. Keep in mind that it may take a brief 
moment until the vehicle has reached the set 
speed.Warning!
G
The set speed stored in memory should only 
be set again if prevailing road conditions 
permit. Possible acceleration or decelera-
tion differences arising from returning to the 
preset speed could cause an accident 
and/or serious injury to you and others.
 
Page 452 of 801
451 Controls in detail
Driving systems
Briefly pull the cruise control lever in 
the direction of arrow4 (
page 447).
The cruise control resumes to the last 
set speed or if no speed is stored, it will 
set and store the current speed.
Remove your foot from the accelerator 
pedal.
The last set speed appears in the multi-
function display for approximately 
5 seconds, and the corresponding 
speedometer segments from the se-
lected speed to the vehicle maximum 
speed are illuminated.
DISTRONIC Plus*
When activated, the DISTRONIC Plus adap-
tive cruise control system increases driv-
ing convenience afforded by the cruise 
control during travel on expressways and 
other major roadways.
If the DISTRONIC Plus distance sensor 
detects a slower moving vehicle direct-
ly ahead, your vehicle speed will be re-
duced so that you follow that vehicle at 
a preset distance.
If there is no vehicle directly ahead of 
you, DISTRONIC Plus will function in 
the same way as the cruise control 
(page 446). 
DISTRONIC Plus functions within a speed 
range of 0 to 120 mph 
(Canada: 0 to 200 km/h).When travelling in Canada in a vehicle not 
registered in Canada, you must switch off 
the radar sensor system. Canadian law 
does not permit the use of the radar sensor 
system for vehicles from outside of Cana-
da. When you switch off the radar sensor 
system, the following functions are deacti-
vated:
BAS Plus* (
page 70)
PRE-SAFE
® Brake* (
page 77)
DISTRONIC Plus* (
page 451)
Park Assist* (
page 476)
Advanced Parking Guidance* 
(page 481)
Blind Spot Assist* (
page 495)
i
The last stored set speed is deleted when 
the engine is turned off. 
Page 453 of 801
452 Controls in detailDriving systemsWarning!
G
DISTRONIC Plus is a convenience system. 
Its speed adjustment reduction capability is 
intended to make the cruise control more ef-
fective and usable when traffic speeds vary. 
It is not however, intended to, nor does it, re-
place the need for extreme care. The re-
sponsibility for the vehicle speed and the 
distance to the vehicle ahead, including 
most importantly brake operation to assure 
safe stopping distance, always remains with 
the driver.
DISTRONIC Plus cannot take street and traf-
fic conditions into account.
Complex driving situations are not always 
fully recognized by DISTRONIC Plus. This 
could result in wrong or missing distance 
warnings.
Warning!
G
DISTRONIC Plus adaptive cruise control is 
no substitute for active driving involvement. 
It does not react to pedestrians or stationary 
objects, nor does it recognize or predict the 
curvature and lane layout or the movement 
of vehicles ahead. DISTRONIC Plus can only 
apply a maximum of 40% of the vehicle’s 
braking power.
DISTRONIC Plus may not detect narrow ve-
hicles possibly driving in front of you, such 
as motorcycles and vehicles driving in an 
offset formation.
It is the driver’s responsibility at all times to 
be attentive to road, weather and traffic con-
ditions and to provide the steering, braking 
and other driving inputs necessary to retain 
control of the vehicle.
High-frequency sources such as toll sta-
tions, speed measuring systems etc. can 
cause the DISTRONIC Plus system to tem-
porarily cease functioning.
Warning!
G
DISTRONIC Plus requires familiarity with its 
operational characteristics. We strongly rec-
ommend that you review the following infor-
mation carefully before operating the 
system.Warning!
G
DISTRONIC Plus cannot take street and traf-
fic conditions into account. Only use 
DISTRONIC Plus if the road, weather and 
traffic conditions make it advisable to travel 
at a steady speed.Warning!
G
Use of DISTRONIC Plus can be dangerous 
on slippery roads. Rapid changes in tire trac-
tion can result in wheel spin and loss of 
control. 
Page 454 of 801
453 Controls in detail
Driving systems
DISTRONIC Plus does not act upon adverse 
sight distance conditions. Do not use 
DISTRONIC Plus during conditions of fog 
and heavy rain, snow or sleet.Warning!
G
DISTRONIC Plus cannot take weather condi-
tions into account. Switch off 
DISTRONIC Plus 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 Plus is switched on. 
Otherwise, 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.
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.Warning!
G
Close attention to road and traffic condi-
tions is imperative at all times, regardless of 
whether or not DISTRONIC Plus is activated.
Use of DISTRONIC Plus can be dangerous 
on winding roads as conditions do not allow 
safe driving at a steady speed.
DISTRONIC Plus may not react to stationary 
objects in the roadway (e.g. a stopped vehi-
cle in a traffic jam or a disabled vehicle). 
DISTRONIC Plus will also not respond to on-
coming vehicles.
Switch off DISTRONIC Plus:
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 Plus will 
continue to maintain the set speed unless 
deactivated.
DISTRONIC Plus is designed and intended 
only to maintain a set speed and keep a set 
distance from moving objects in front of it.
i
Do not use DISTRONIC Plus if you are driv-
ing on a road with steep uphill or downhill slopes.
i
Due to its radar-emitting nature DISTRONIC 
Plus may have an appearance similar to a radar 
detector to law enforcement officials. You may 
want to refer to this section of your Operator’s 
Manual when asked. 
Page 455 of 801
454 Controls in detailDriving systems
DISTRONIC Plus displays in multifunc-
tion display
1Speed of the vehicle ahead
2Set speed
3Distance warning lamp
If DISTRONIC Plus is activated, the 
marker2 indicates the set speed.When DISTRONIC Plus detects a vehicle 
driving ahead of you, the ring on the speed-
ometer dial lights up between the speed of 
the vehicle ahead of you and set speed2.
If DISTRONIC Plus calculates that there is 
a danger of collision:
The distance warning lampl in the 
instrument cluster comes on.
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 distance warning lampl 
goes out when the necessary distance 
to the vehicle ahead is again 
established.
i
USA only:
This device has been approved by the FCC as a 
“Vehicular Radar System”. The radar sensor is 
intended for use in an automotive radar system 
only. Removal, tampering, or altering of the de-
vice will void any warranties, and is not permitted 
by the FCC. Do not tamper with, alter, or use in 
any non-approved way.
Any unauthorized modification to this device 
could void the user’s authority to operate the 
equipment.
i
Canada only:
This device complies with RSS-210 of Industry 
Canada. Operation is subject to the following 
two conditions:
(1) This device may not cause interference, and
(2) this device must accept any interference re-
ceived, including interference that may 
cause undesired operation of the device.
Removal, tampering, or altering of the device will 
void any warranties, and is not permitted. Do not 
tamper with, alter, or use in any non-approved 
way.
Any unauthorized modification to this device 
could void the user’s authority to operate the 
equipment.
i
The vehicle speed displayed on the speed-
ometer can briefly vary from the speed setting 
on the DISTRONIC Plus system. 
Page 456 of 801
455 Controls in detail
Driving systems
Displaying the distance graphic
In the “Assistance” menu under “Distance 
Display” you see the current settings for 
DISTRONIC Plus. The information shown in 
the multifunction display depends on 
whether DISTRONIC Plus is activated or 
deactivated.
Warning!
G
An intermittent warning sounds and the dis-
tance warning lampl in the instrument 
cluster is illuminated if the DISTRONIC Plus 
system calculates that the distance to the 
vehicle ahead and your vehicle’s current 
speed indicate that DISTRONIC Plus will not 
be capable of slowing the vehicle sufficiently 
to maintain the preset following distance, 
which creates a danger of a collision.
Immediately brake your vehicle to increase 
the distance between your vehicle and the 
vehicle in front of you. The warning sound is 
intended as a final caution that you have not 
interceded with your own braking inputs to 
avoid a potentially dangerous situation. Do 
not wait for the operation of the warning sig-
nal to intercede with your own braking, as 
that will result in potentially dangerous 
emergency braking which will not always re-
sult in an impact being avoided.
Tailgating increases the risk of an accident.
Warning!
G
DISTRONIC Plus brakes your vehicle with a 
maximum of 13 ft/s
2. This corresponds to 
about 40% of the maximum deceleration 
ability of your vehicle. 
You must also apply the brakes yourself to 
avoid a collision. DISTRONIC Plus brakes 
the vehicle in an effort to restore the preset 
distance or to maintain the speed. The brake 
pedal is automatically applied as this hap-
pens which results in the brake pedal mov-
ing.
Keep driver’s foot area clear at all times, in-
cluding the area under the brake pedal. Ob-
jects stored in this area may impair pedal 
movement which could interfere with the 
braking ability of the DISTRONIC Plus sys-
tem.
Do not place your foot under the brake pedal 
– your foot could become caught.
Warning!
G
If you do not receive visual or acoustic warn-
ing signals during a critical traffic situation, 
DISTRONIC Plus has either not recognized 
the collision risk, has been deactivated or is 
malfunctioning.
Remember, whether or not DISTRONIC Plus 
is operating, it is ultimately always the driv-
ers responsibility to apply the brakes in or-
der to control the vehicle and avoid a 
collision.i
For activating or deactivating the 
DISTRONIC Plus system, see “Activating 
DISTRONIC Plus” (
page 457) or “Deactivating 
DISTRONIC Plus” (page 463).
 
Page 457 of 801
456 Controls in detailDriving systems
Press ( or & to select the 
“Assistance” menu.
Press % or $ to select the 
“Distance Display” function.
Press #.
The DISTRONIC Plus distance graphic 
appears and you will see one of the fol-
lowing displays on the multifunction 
display.DISTRONIC Plus activated
When you turn DISTRONIC Plus on, you will 
see the set speed in the multifunction dis-
play for about 5 seconds. You then see the 
following display in the multifunction dis-
play.
1DISTRONIC Plus activated
2Your vehicle
3Preset distance threshold to vehicle 
ahead
4Vehicle ahead, if detectedDISTRONIC Plus deactivated
If DISTRONIC Plus is deactivated, the stan-
dard display of DISTRONIC Plus appears in 
the multifunction display.
1Vehicle ahead, if detected
2Actual distance to vehicle ahead
3Preset distance threshold to vehicle 
ahead
4Your vehicle
i
The menu overview can be found on 
(
page 289).
 
Page 458 of 801
457 Controls in detail
Driving systems
DISTRONIC Plus lever
The DISTRONIC Plus system is operated by 
means of the DISTRONIC Plus lever.
1Setting current or higher speed
Adjustment in 1 mph increments (to 
the resistance point) or 5 mph 
increments (past the resistance point) 
(Canada: 1 km/h or 10 km/h)
2Setting current or lower speed
Adjustment in 1 mph increments (to 
the resistance point) or 5 mph 
increments (past the resistance point) 
(Canada: 1 km/h or 10 km/h)
3Canceling DISTRONIC Plus
4Activating DISTRONIC Plus or resum-
ing to last set speed5Setting target distance
Activating DISTRONIC Plus
You can activate DISTRONIC Plus when:
you are driving slower than 20 mph 
(30 km/h) and DISTRONIC Plus has 
detected a vehicle ahead of you
you are driving above 20 mph 
(30 km/h)
If DISTRONIC Plus has not been activated 
after pressing the DISTRONIC Plus lever, 
you will see the message: “DISTRONIC 
PLUS - - - mph” (Canada: “DISTRONIC PLUS 
- - - kmh”) in the multifunction display.
Warning!
G
When DISTRONIC Plus is braking, the brake 
pedal is retracted (i.e. depressed automati-
cally). The pedals’ range of motion must not 
be impeded by any obstacles:
Do not place any objects in the footwell.
Make sure that the floor mats and car-
pets are securely in place.
Do not rest your foot underneath the 
brake pedal, as it could otherwise be 
trapped.
You could otherwise cause an accident and 
injure yourself and others.
Warning!
G
When DISTRONIC Plus is switched on, the 
vehicle can be braked. You should therefore 
switch off DISTRONIC Plus if the vehicle 
must be towed.i
The maximum speed you can set is 120 mph 
(Canada: 200 km/h). 
Page 459 of 801
458 Controls in detailDriving systemsIn the following cases you cannot activate 
DISTRONIC Plus:
up to 2 minutes after starting the en-
gine
if the engine is switched off
if you step on the brake pedal while 
driving 
the vehicle is secured with the elec-
tronic parking brake
if the gear selector lever is in park 
positionP, reverse gearR, or neutral 
positionN
if ESP
® is switched off
if the hood is open
if the driver’s door is open and the driv-
er has not fastened his or her seat belt
if the radar sensors are switched off 
(page 307).Switching on while driving
Tap DISTRONIC Plus lever up1 or 
down2 until desired speed is set.
DISTRONIC Plus is switched on.
or
Pull DISTRONIC Plus lever briefly in di-
rection of arrow4 to call up speed 
last set (
page 463).
DISTRONIC Plus is switched on.
Take your foot off the accelerator ped-
al.
Your vehicle adapts its speed to the ve-
hicle ahead, observing the set speed as 
a maximum value.
i
Under 20 mph (30 km/h), you can only 
switch on DISTRONIC Plus if the vehicle ahead of 
you has been detected and is shown on the mul-
tifunction display. If you no longer see the vehi-
cle in front of you on the multifunction display 
and if it is no longer detected because it has 
changed lanes, for example, DISTRONIC Plus 
switches off and you will hear a signal.
i
If you do not completely lift your foot off the 
accelerator pedal, the message“DISTRONIC 
PLUS Override” appears on the multifunction 
display. The distance to a slower-driving vehicle 
will not be set. You will drive at the speed you 
dictate by pressing the accelerator pedal. 
Page 460 of 801
459 Controls in detail
Driving systems
Switching on when approaching a sta-
tionary vehicle
If the vehicle in front of you is stationary, 
you can only switch on DISTRONIC Plus if 
your vehicle is also at a standstill.
Tap DISTRONIC Plus lever up1 or 
down2 until desired speed is set.
DISTRONIC Plus is switched on.
or
Pull DISTRONIC Plus lever briefly in di-
rection of arrow4 to call up speed 
last set (
page 463).
DISTRONIC Plus is switched on.Starting off
When the vehicle in front of you starts off:
Remove your foot from the brake 
pedal.
Pull DISTRONIC Plus lever briefly in di-
rection of arrow4.
or
Briefly step on the accelerator pedal.
Your vehicle starts off and adapts its speed 
to the vehicle in front of you.Driving
If no vehicle is driving ahead of you, 
DISTRONIC Plus functions like the cruise 
control (
page 446).
When DISTRONIC Plus detects that the ve-
hicle in front of you is driving more slowly, 
it brakes the vehicle in order to keep the 
distance specified by you.
When DISTRONIC Plus detects that the ve-
hicle in front of you is driving faster, the ve-
hicle accelerates up to the set speed.
i
It is helpful to switch on the DISTRONIC Plus 
display in the instrument cluster (
page 455) 
since you can only switch on DISTRONIC Plus un-
d e r  a  s p e e d  o f  2 0 m p h  ( 3 0 k m / h )  w h e n  a  v e h i c l e  
has been detected in front of you.
i
You can adjust the set speed using the 
DISTRONIC Plus lever and the target distance 
using the distance setting switch on the 
DISTRONIC Plus lever (
page 464).
i
If DISTRONIC Plus is switched off, 
PRE-SAFE
® Brake* (
page 77) will warn of an 
impending collision if this function has been ac-
tivated with the instrument cluster control sys-
tem (
page 303).
Warning!
G
When you step on the brake pedal, you 
switch off DISTRONIC Plus except when the 
vehicle is at a standstill. DISTRONIC Plus will 
no longer brake your vehicle. You are always 
responsible for maintaining a distance from 
other vehicles, observing road speeds and 
braking well in advance.