Page 458 of 480

457 Technical terms
Overspeed range
Engine speeds within the red marking
on the tachometer dial, see “Tachome-
ter” (
page 133). Avoid this engine
speed range, as it may result in serious
engine damage that is not covered by
the Mercedes-Benz Limited Warranty.
Parktronic (Parking assist)*
System which uses visual and acoustic
signals to assist the driver during park-
ing maneuvers.
Poly-V-belt drive
Drives engine-components (alternator,
AC compressor, etc.) from the engine.Power train
Collective term designating all compo-
nents used to generate and transmit
motive power to the drive axles, includ-
ing
engine
clutch/torque converter
transmission
transfer case
drive shaft
differential
axle shafts/axles
Production options weight
(
page 311)Program mode selector switch
Used to switch the automatic transmis-
sion between standard operation (S)
and comfort operation (C).
SL 55 AMG with steering wheel gear-
shift control and manual shift program:
In addition to S and C (for regular S or
comfort C operation, see above), you
can use MANUAL for manual shift pro-
gram.
PSI
(P
ounds p
er s
quare i
nch)
(
page 312)
Recommended tire inflation pressure
(page 312)
REST
(Residual Engine Heat Utilization)
Feature that uses the engine heat
stored in the coolant to heat the vehi-
cle interior for a short time after the en-
gine has been turned off.
Page 459 of 480

458 Technical termsRetractable hardtop
Hardtop roof that can be opened and
closed at the push of a button and
stored in the trunk.
Rim
(
page 312)
Roll bar
Occupant protection system which
consists of tubular steel sheathed in
plastic. The roll bar is lowered into the
car body during normal driving condi-
tions and raised automatically. It may
also be manually raised and lowered by
operating a button during critical driv-
ing situations.
RON
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
ANTI-KNOCK INDEX.Shift lock
When the vehicle is parked, this lock
prevents the gear selector lever from
being inadvertently moved out of posi-
tion P without SmartKey turned and
brake pedal depressed.
Sidewall
(
page 312)
SRS
(Supplemental 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
(Tele
matic 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-
vided that the vehicle’s battery is
charged, properly connected, not dam-
aged and cellular and GPS coverage is
available.
Tightening torque
Force times lever arm (e.g. a lug
wrench) with which threaded fasteners
such as wheel bolts are tightened.
TIN
(T
ire I
dentification N
umber)
(
page 312)
Tire load rating
(page 312)
Page 460 of 480

459 Technical terms
Tire ply composition and material used
(
page 312)
Tire speed rating
(page 312)
Traction
(page 312)
Tread
(page 312)
Treadwear indicators
(page 312)
Uniform Tire Quality Grading Standards
(page 313)
Vehicle capacity weight
(page 313)Vehicle level control
The ground clearance of the vehicle is
automatically controlled according to a
selected setting and speed. The driver
can choose manually within a range of
ground clearance, for example on very
rough roads.
Vehicle maximum load on the tire
(
page 313)
VIN
(Vehicle 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.).Wind screen
Screen for deflecting wind from the ve-
hicle interior when the hardtop is low-
ered.
Xenon headlamps
Headlamps which use an electric arc as
the light source and produce a more in-
tense light than filament headlamps.