Page 180 of 384

180 Controls in detailDriving systemsWarning!
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
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.
Page 248 of 384

248OperationTires and wheelsTire pressure changes by approximately
1.5 psi (0.1 bar) per 18°F (10°C) of air
temperature change. Keep this in mind
when checking tire pressure where the
temperature is different from the outside
temperature.
Tire temperature and tire pressure also in-
crease while driving, depending on the
driving speed and the tire load.Check the spare tire periodically for condi-
tion and inflation pressure. Spare tires will
age and become worn over time even if
never used, and thus should be inspected
and replaced when necessary or after a
maximum of six years.Checking tire pressure electronically*
The tire inflation pressure monitor only
functions on wheels that are equipped with
the proper electronic sensors. It monitors
the tire inflation pressure, as selected by
the driver, in all four tires. A warning is is-
sued to alert you to a decrease in pressure
in one or more of the tires.
Tire pressure inquiries are made using the
multifunction display (
page 117). The in-
flation pressures are displayed only after a
few minutes’ travel time.
You can select the unit of measure used for
the tire inflation pressure by changing the
setting in the control system (
page 117).
iThe pressures listed for light loads are
minimum values offering high driving
comfort.
Increased inflation pressures listed for
heavier loads may also be used for light
loads. These higher pressures produce
favorable handling characteristics. The
ride of the vehicle, however, will be
somewhat harder. Never exceed the
max. values or inflate tires below the
min. values listed on the fuel filler flap.
Warning!
G
Follow recommended inflation pressures.
Do not overinflate tires. Overinflated tires
can result in sudden deflation (blowout) be-
cause they are more likely to become punc-
tured or damaged by road debris, potholes
etc.
Do not underinflate tires. Underinflated tires
wear unevenly, adversely affect handling
and fuel economy, and are more likely to fail
from being overheated.
Do not overload the tires by exceeding the
specified vehicle capacity weight (as indicat-
ed by the label on the pillar in the driver’s
door opening). Overloading the tires can
overheat them, possibly causing a blowout.
iPossible differences between the read-
ings of a tire pressure gauge of an air
hose, e.g. gas station equipment, and
the vehicle’s control system can occur.
The readings issued by the control sys-
tem are more precise.
Page 351 of 384

351 Technical terms
RON
(R
esearch O
ctane N
umber)
The Research Octane Number for gaso-
line as determined by a standardized
method. It is an indication of a gaso-
line's ability to resist undesired detona-
tion (knocking). The average of both
the ->MON (Motor Octane Number)
and RON (Research Octane Number) is
posted at the pump, also known as AN-
TI-KNOCK INDEX.
Shift lock
When the vehicle is parked, this lock
prevents the transmission selector le-
ver from being inadvertently moved out
of positionP without key turned and
brake pedal depressed.
Speedshift
Steering wheel gearshift control and
manual shift program. In the manual
shift program mode you can change
the gears yourself on the steering
wheel or by using the selector lever. SRS
(S
upplemental R
estraint S
ystem)
Seat belts, emergency tensioning de-
vice and airbags. Though independent
systems, they are closely interfaced to
provide effective occupant protection.
Tele Aid System
(T
elematic A
larm I
dentification on D
e-
mand)
The Tele Aid system consists of three
types of response: automatic and man-
ual emergency, roadside assistance
and information. Tele Aid is initially ac-
tivated by completing a subscriber
agreement and placing an acquain-
tance call.
The Tele Aid system is operational pro-
viding that the vehicle’s battery is
charged, properly connected, not dam-
aged and cellular and GPS coverage is
available.Telematics
A combination of the terms “telecom-
munications” and “informatics”.
Tightening torque
Force times lever arm (e.g. a lug
wrench) with which threaded fasteners
such as wheel bolts are tightened.
Tire speed rating
Part of tire designation; indicates the
speed range for which a tire is ap-
proved.
Traction
Force exerted by the vehicle on the
road via the tires.
VIN
(V
ehicle I
dentification N
umber)
The number set by the manufacturer
and placed on the body to uniquely
identify each vehicle produced.
Voice control system*
Voice control system for car phones,
portable cell phones and audio sys-
tems (radio, CD, etc.).