
235 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 239). 
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 traffic and road conditions 
and to provide the steering, braking and oth-
er 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. However, it 
is not intended to, nor does it, replace the 
need for extreme care. The responsibility for 
the vehicle speed and the distance to the ve-
hicle ahead, including most importantly 
brake operation to assure safe stopping dis-
tance, 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. 

245 Controls in detail
Driving systems
The most likely cause for a malfunctioning 
system is a dirty sensor (located behind 
the hood grille), especially at times of snow 
and ice or heavy rain. In such a case, 
Distronic will switch off, and the message Currently unavailable See Operator’s 
Manual
 appears in the multifunction dis-
play.
For cleaning and care of the Distronic sen-
sor, see “Cleaning the Distronic system 
sensor” (page 351).Turns and bends
In turns or bends, 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.
iIf the message 
Currently unavailable 
See Operator’s Manual 
disappears 
during driving and the last speed stored 
flashes for approximately five seconds, 
the dirt (e.g. slush) has dissolved; 
Distronic works again. 

250 Controls in detailDriving systemsParktronic system (Parking assist)*
The Parktronic system is an electronic aid 
designed to assist the driver during park-
ing maneuvers. It visually and audibly indi-
cates the relative distance between the 
vehicle and an obstacle.
The Parktronic system is automatically ac-
tivated when you switch on the ignition, re-
lease the parking brake, and placed the 
gear selector lever in positionD,R,orN.
The Parktronic system deactivates at 
speeds over approximately 11 mph 
(18 km/h). At lower speeds the Parktronic 
system turns on again.
The Parktronic system also deactivates 
when you place the gear selector lever in 
positionP or depress the parking brake 
pedal.The Parktronic system monitors the sur-
roundings of your vehicle with six sensors 
in the front bumper and four sensors in the 
rear bumper.
1Sensors in the front bumper
Range of the sensors
To function properly, the sensors must be 
free of dirt, ice, snow and slush. Clean the 
sensors regularly, being careful not to 
scratch or damage the sensors, see 
“Cleaning the Parktronic system* sensors” 
(
page 351).
Warning!
G
Parktronic is a supplemental system. It is 
not intended to, nor does it replace, the 
need for extreme care. The responsibility 
during parking and other critical maneuvers 
always rests with the driver.
Special attention must be paid to objects 
with smooth surfaces or low silhouettes 
(e.g. trailer couplings, painted posts, or road 
curbs). Such objects may not be detected by 
the system and can damage the vehicle.
The operational function of the Parktronic 
system can be affected by dirty sensors, es-
pecially at times of snow and ice, see 
“Cleaning the Parktronic system* sensors” 
(page 351).
Interference caused by other ultrasonic sig-
nals (e.g. working jackhammers, car wash or 
the air brakes of trucks) can cause the sys-
tem to send erratic indications, and should 
be taken into consideration.
Warning!
G
Make sure no persons or animals are in the 
area in which you are maneuvering. You 
could otherwise injure them. 

251 Controls in detail
Driving systems
Front sensors
Rear sensorsMinimum distance
If the system detects an obstacle in this 
range, all the distance warning segments 
illuminate and you hear a warning signal. If 
the obstacle is closer than the minimum 
distance, the actual distance might no 
longer be indicated by the system.Center
approx. 40 in (100 cm)
Corners
approx. 24 in (60 cm)
Center
approx. 48 in (120 cm)
Corners
approx. 32 in (80 cm)
!During parking maneuvers, pay special 
attention to objects located above or 
below the height of the sensors (e.g. 
planters or trailer hitches). The 
Parktronic system will not detect such 
objects at close range and damage to 
your vehicle or the object may result.
Ultrasonic signals from outside sourc-
es (e.g. truck air brakes, car wash or 
jackhammers) may impair the opera-
tion of the Parktronic system.
Center
approx. 8 in (20 cm)
Corners
approx. 6 in (15 cm) 

252 Controls in detailDriving systemsWarning indicators
Visual signals indicate to the driver the rel-
ative distance between the sensors and an 
obstacle. The warning indicator for the 
front area is located above the center air 
vents in the dashboard. The warning indi-
cator for the rear area is integrated in the 
rear trim.Front area warning indicator1Left side of the vehicle
2Right side of the vehicle
3Readiness indicatorsEach warning indicator is divided into five 
yellow and two red segments for either 
side of the vehicle. The Parktonic system is 
operational when the yellow readiness 
indicators3 are illuminated.
The position of the gear selector lever de-
termines which warning indicators will be 
activated.
As your vehicle approaches an object, one 
or more segments will come on, depending 
on the distance. When the seventh seg-
ment illuminates, you have reached the 
minimum distance.
Front area: An intermittent acoustic 
warning will sound as the first red dis-
tance segment illuminates and a con-
stant acoustic warning lasting a 
maximum of two seconds will sound for 
the second red distance segment. The 
signal is canceled when the gear selec-
tor lever is placed in positionP or the 
parking brake is activated.
Rear area: An intermittent acoustic 
warning will sound as the first red dis-
tance segment illuminates and a con-
stant acoustic warning lasting a 
maximum of two seconds will sound for 
the second red distance segment. The 
signal is canceled when the gear selec-
tor lever is placed in position D,P or 
the parking brake is activated.
Gear selector le-
ver position
Warning indicator
D
Front area activated
R or N
Front and rear area 
activated
P
Neither activated 

396 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
H
Tire pres. monitor
reactivated
The tire pressure monitoring system is 
using the current pressure values as the 
basis for monitoring.
Tire pressure
 
displayed only
after driving 
a few mins. 
The tire inflation pressure is being 
checked.
Tire pres. monitor
temporarily
unavailable
The tire pressure monitoring system* is 
unable to monitor the tire inflation pres-
sure due to
the presence of several wheel sensors 
in the vehicle.
excessive wheel sensor tempera-
tures.
a nearby radio interference source.
unrecognized wheel sensors mount-
ed.
Remove any extra wheel sensors from 
the vehicle.
As soon as the causes of the malfunction 
have been removed, the tire pressure 
monitoring system automatically be-
comes active again.
Warning!
G
Do not drive with a flat tire. A flat tire affects 
the ability to steer or brake the vehicle.
You may lose control of the vehicle. Contin-
ued driving with a flat tire will cause
 excessive heat build-up and possibly a fire. 

397 Practical hints
What to do if …
Display symbol
Display messages
Possible cause
Possible solution
H
Tire pres. monitor
reactivated
The tire pressure monitoring system is 
using the current pressure values as the 
basis for monitoring.
Tire pressure
 
displayed only
after driving 
a few mins. 
The tire inflation pressure is being 
checked.
Tire pres. monitor
temporarily
unavailable
The tire pressure monitoring system* is 
unable to monitor the tire inflation pres-
sure due to
the presence of several wheel sensors 
in the vehicle.
excessive wheel sensor tempera-
tures.
a nearby radio interference source.
unrecognized wheel sensors mount-
ed.
Remove any extra wheel sensors from 
the vehicle.
As soon as the causes of the malfunction 
have been removed, the tire pressure 
monitoring system automatically be-
comes active again.
Warning!
G
Do not drive with a flat tire. A flat tire affects 
the ability to steer or brake the vehicle.
You may lose control of the vehicle. Contin-
ued driving with a flat tire will cause
 excessive heat build-up and possibly a fire. 

398 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
H
Reactivate
tire pres. monitor
after corr. pres.
There was a tire pressure warning mes-
sage.
The yellow warning lamp for the tire pres-
sure monitoring system comes on and 
you have not reactivated the system 
since the last tire pressure warning mes-
sage. 
Reactivate the tire pressure monitor-
ing system after correcting the tire 
pressure values (
page 324).
Tire pres. monitor
deactivated
Drive to workshop
The tire pressure monitoring system is 
malfunctioning. 
A wheel without proper sensor was in-
stalled.
Have the tire pressure monitoring sys-
tem checked by an authorized 
Mercedes-Benz Center.
Change the wheel (
page 425).
Warning!
G
Do not drive with a flat tire. A flat tire affects 
the ability to steer or brake the vehicle.
You may lose control of the vehicle. Contin-
ued driving with a flat tire will cause exces-
sive heat build-up and possibly a fire.