wheel speed MERCEDES-BENZ R-Class 2012 W251 Owner's Guide

time, or adjusts the vehicle's speed to the
last speed stored.
Setting the specified minimum distance
You can set the specified minimum distance
for DISTRONIC by varying the time span
between one and two seconds. This time span
determines the distance that DISTRONIC
should maintain from the vehicle in front,
depending on the road speed. You can see
this distance in the multifunction display
( Y page 178).
GWARNING
It is up to the driver to exercise discretion to
select the appropriate setting given road
conditions, traffic, driver's preferred driving
style and applicable laws and driving
recommendations for safe following distance.
XTo increase: turn thumbwheel ; towards
= .
DISTRONIC then maintains a greater
distance between your vehicle and the
vehicle in front.XTo decrease: turn thumbwheel ;
towards :.
DISTRONIC then maintains a shorter
distance between your vehicle and the
vehicle in front.
i Make sure that you maintain the
minimum distance to the vehicle in front as
required by law. Adjust the distance to the
vehicle in front if necessary.
DISTRONIC displays in the
speedometer
When DISTRONIC is activated, one or
two segments in the set speed range light up.
i For design reasons, the speed displayed
in the speedometer may differ slightly from
the speed set for DISTRONIC.
If DISTRONIC detects a vehicle in front,
segments ; between the speed of the
vehicle in front : and stored speed = light
up.
GWARNING
An intermittent warning sounds and the
distance warning lamp · in the instrument
cluster is illuminated if the Distronic system
calculates that the distance to the vehicle
ahead and your vehicle's current speed
indicate that the Distronic will not be capable
of slowing the vehicle sufficiently to maintain
the preset following distance, which creates
a danger of a collision.
Immediately brake the vehicle to increase
your distance to the preceding vehicle. The
warning sound is intended as a final caution
in which you should intercede with your own
braking inputs to avoid a potentially
dangerous situation. Do not wait for the
operation of the warning signal to intercede
with your own braking. This will result in
potentially dangerous emergency braking
which will not always result in an impact being
avoided.
Tailgating increases the risk of an accident.
Driving systems177Driving and parkingZ

The vehicle is automatically lowered to high-
speed level when you:
R drive faster than 70 mph (112 km/h)
R drive between 60 mph (96 km/h) and
70 mph (112 km/h) for approximately
20 seconds.
The individual vehicle levels differ from
highway level as follows:
R +1.97 in (+ 50 mm) at the raised level
R +/-0 in (+/-0 mm) at the highway level
R -0.47 in (-12 mm) at the high-speed level
i The high-speed level is not available if you
are pulling a trailer. Observe the notes on
driving with a trailer ( Y page 191).
i Observe the speed limitations. Drive
carefully at an appropriate speed.
Raised level
Only select raised level when this is
appropriate for the road conditions.
Otherwise, fuel consumption may increase
and handling may be affected.
If you select the raised level at a speed of over
40 mph (64 km/h) the Level Selection
Not Permitted message appears in the
multifunction display.XStart the engine.
Indicator lamp ; is not lit:
XPress button :.
Indicator lamp ; flashes. The vehicle rises
to raised level.While the adjustment is taking place, a
message appears in the multifunction
display, e.g.:
If you press the V, U , * or &
button on the multifunction steering wheel,
the message will disappear.
Once the vehicle has reached raised level,
indicator lamp ; remains lit. A message
appears in the multifunction display for
approximately five seconds, e.g.:
The level is automatically taken up to highway
level if you drive faster than 25 mph
(40 km/h).
Highway level
! Make sure that there is enough ground
clearance when the vehicle is being
lowered. It could otherwise hit the ground,
damaging the underbody.
XMake sure that the doors are closed.XStart the engine.182Driving systemsDriving and parking

If indicator lamp ; is lit:XPress button :.
Indicator lamp ; flashes. The vehicle is
lowered to highway level.
While the adjustment is taking place, a
message appears in the multifunction
display, e.g.:
If you press the V, U , * or &
button on the multifunction steering wheel,
the message will disappear.
Once highway level has been reached,
indicator lamp ; goes out. A message
appears in the multifunction display for
approximately five seconds, e.g.:
The level is automatically raised from high-
speed level to highway level if the speed falls
below 40 mph (64 km/h). The level is
automatically taken up to highway level if you
drive faster than 25 mph (40 km/h).
4MATIC (permanent four-wheel drive)
4MATIC ensures that all four wheels are
permanently driven. Together with ESP ®
and
4ETS , it improves the traction of your vehicle
whenever a drive wheel spins due to
insufficient grip.
GWARNING
If a drive wheel is spinning due to insufficient
traction:
R While driving off, apply as little throttle as
possible.
R While driving, ease up on the accelerator
pedal.
R Adapt your speed and driving style to the
prevailing road conditions.
Failure to observe these guidelines could
cause the vehicle to skid.
The 4MATIC cannot prevent accidents
resulting from excessive speed.
! Never tow the vehicle with one axle
raised. This may damage the transfer case.
Damage of this sort is not covered by the
Mercedes-Benz Limited Warranty. All
wheels must remain either on the ground
or be fully raised. Observe the instructions
for towing the vehicle with all wheels in full
contact with the ground.
i In wintry driving conditions, the maximum
effect of 4MATIC can only be achieved if
you use winter tires ( M+S tires), with snow
chains if necessary.
! When testing the parking brake, operate
the vehicle only briefly (for a maximum of
ten seconds) on a brake test dynamometer.
When doing this, turn the key to position
0 or 1 in the ignition. Failure to do this can
cause damage to the drive train or the
brake system.
! Function or performance tests may only
be performed on a 2-axle dynamometer. If
you wish to operate the vehicle on such a
dynamometer, please consult an
authorized Mercedes-Benz Center
beforehand. You could otherwise damage
the drive train or the brake system.
Driving systems183Driving and parkingZ

Please observe the following when towing a
trailer:
R To acquaint yourself with driving with a
trailer and with the resulting changes to
handling, you should practice cornering,
stopping and reversing in a traffic-free
location.
R Before driving, check:
- the trailer tow hitch
- the safety switch for braked trailers
- the safety chains
- the electrical connections
- the lights
- the wheels
R Adjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer.
R If the trailer features electronically
controlled brakes, pull away the vehicle/
trailer combination carefully, manually
brake using the brake controller, and check
the brakes for correct function.
R Secure any objects on the trailer to prevent
the cargo from slipping when the vehicle is
in motion.
R If you couple up a trailer, regularly check
the cargo for secure fastening and make
sure that the trailer lamps and (if
applicable) the trailer brakes are
functioning correctly.
R Bear in mind that the handling will be less
stable when towing a trailer than when
driving without one. Avoid sudden steering
movements.
R The vehicle/trailer combination is heavier,
accelerates more slowly, has a decreased
gradient climbing capability and a longer
braking distance.
It is more susceptible to side winds and
requires more careful steering.
R If possible, avoid abrupt braking. Depress
the brake pedal moderately at first, so that
the trailer can activate its own brakes. Then
increase the pressure on the brake pedal.R If the automatic transmission continues to
shift back and forth between two gears
when driving up or downhill, restrict the
shift range. Select shift range 4, 3, 2, or 1.
A lower gear and lower speed reduce the
risk of engine failure.
R When driving downhill, shift to a lower gear
to utilize the engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if
installed, the trailer brakes.
R If the coolant temperature increases
dramatically while the air-conditioning
system is switched on, switch off the air-
conditioning system.
Coolant heat can additionally be dissipated
by opening the windows and by setting the
blower fan and the interior temperature to
maximum.
R When overtaking, pay particular attention
to the extended length of your vehicle/
trailer combination.
Due to the length of your vehicle/trailer
combination, you will have to travel an
additional distance beyond the vehicle you
are overtaking before returning to the
previous lane.
Decoupling a trailer
GWARNING
Vehicles with AIRMATIC: While you are
coupling or decoupling a trailer, make sure
nobody locks or unlocks the vehicle and/or
opens or closes doors or the tailgate.
The vehicle's level could change and you
could endanger yourself and/or others as a
result.
Make sure that you do not operate the ADS
switch or the vehicle level control system
when coupling/decoupling the trailer.
XMake sure that the automatic transmission
is set to position P.XApply the vehicle's parking brake.Trailer towing193Driving and parkingZ

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 24).
Important safety notes
You will find an illustration of the instrument
cluster in the "At a glance" section
( Y page 29).
GWARNING
A driver's attention to the road and traffic
conditions must always be his/her primary
focus when driving.
For your safety and the safety of others,
selecting features through the multifunction
steering wheel should only be done by the
driver when traffic and road conditions permit
it to be done safely.
Bear in mind that at a speed of just 30 mph
(approximately 50 km/h ), your vehicle is
covering a distance of 44 feet (approximately
14 m) every second.
GWARNING
No messages will be displayed if either the
instrument cluster or the multifunction
display is inoperative.
As a result, you will not be able to see
information about your driving conditions,
such as
R speed
R outside temperature
R warning/indicator lamps
Rmalfunction/warning messages
R failure of any systems
Driving characteristics may be impaired.
If you must continue to drive, do so with added
caution. Contact an authorized Mercedes-
Benz Center as soon as possible.GWARNING
Malfunction and warning messages are only
indicated for certain systems and are
intentionally not very detailed. The
malfunction and warning messages are
simply a reminder with respect to the
operation of certain systems. They do not
replace the owner's and/or driver's
responsibility to maintain the vehicle's
operating safety. Have all required
maintenance and safety checks performed on
the vehicle. Bring the vehicle to an authorized
Mercedes-Benz Center to address the
malfunction and warning messages.
Displays and operation
Tachometer
The red band in the tachometer indicates the
engine's overrevving range.
! Do not drive in the overrevving range, as
this could damage the engine.
The fuel supply is interrupted to protect the
engine when the red band is reached.
Outside temperature display
The outside temperature display is in the
multifunction display ( Y page 200).
GWARNING
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Indicated temperatures just above the
freezing point do not guarantee that the road
198Displays and operationOn-board computer and displays

surface is free of ice. The road may still be icy,
especially in wooded areas or on bridges.
Changes in the outside temperature are
displayed after a short delay.
Speedometer with segments
The segments in the speedometer indicate
which speed range is available.
DISTRONIC ( Y page 173) activated:
One or two segments in the set speed range
light up.
DISTRONIC detects a vehicle in front:
The segments between the speed of the
vehicle in front and the stored speed light up.
Operating the on-board computer
The on-board computer is activated as soon
as you turn the SmartKey to position 1 in the
ignition lock.
You can control the multifunction display and
the settings in the on-board computer using
the buttons on the multifunction steering
wheel.
:Multifunction display;~
Rejects or ends a call
Exits phone book/redial memory
6
Makes or accepts a call
Switches to the redial memory
WX
Selects submenus in the Settings
menu
Changes values
Adjusts the volume
?
Switches on the Voice Control
System; see the separate operating
instructions=VU
Selects a menu: scrolls back and
forth
A
Switches off the Voice Control
System; see the separate operating
instructions&*
Press briefly:
Scrolls back and forth within a menu
In the Audio menu: selects a stored
station, an audio track or a video
scene
In the Telephone menu: switches to
the phone book and selects a name
or a telephone number&*
Press and hold:
In the Audio menu: selects the
previous/next station or selects an
audio track using rapid scrolling
In the Telephone menu: starts rapid
scrolling through the phone bookDisplays and operation199On-board computer and displaysZ

FunctionETrip computer menu (Y page 210)FTelephone menu (Y page 211)Standard display menu
Standard displayXPress the V or U button on the
steering wheel to select the standard
display.
Standard display
:Trip odometer;Odometer
You can select the following functions in the
Standard display menu using the & or
* button:
R tire pressure loss warning system
( Y page 329) (Canada only)
R tire pressure monitor ( Y page 331) (USA
only)
R coolant temperature ( Y page 202)
R digital speedometer or outside
temperature ( Y page 202)
R ASSYST PLUS service interval display
( Y page 287)
XTo reset the trip odometer: press and
hold the . reset button in the instrument
cluster until the trip odometer is reset.
Displaying the coolant temperature
GWARNING
Driving when your engine is overheated can
cause some fluids which may have leaked into
the engine compartment to catch fire. You
could be seriously burned.
Steam from an overheated engine can cause
serious burns which can occur just by opening
the engine hood. Stay away from the engine
if you see or hear steam coming from it.
Stop the vehicle in a safe location away from
other traffic. Turn off the engine, get out of the
vehicle and do not stand near the vehicle until
the engine has cooled down.XPress the V or U button on the
steering wheel to select the standard
display.XPress the & or * button to select the
coolant temperature.
Under normal driving conditions, with the
correct anti-corrosion and antifreeze additive
concentration, the reading may rise to
248 ‡(120 †).
! If the coolant temperature exceeds
248 ‡(120 †) do not continue driving. The
engine will otherwise be damaged.
Displaying the digital speedometer or
outside temperature
If you have selected the digital speedometer
for the status bar ( Y page 206), the outside
temperature is displayed here.
202Menus and submenusOn-board computer and displays

XPress the V or U button on the
steering wheel to select the standard
display.XPress the & or * button to select
digital speedometer or the outside
temperature.
Digital speedometer
Outside temperature
Audio menu
Selecting a radio station
i SIRIUS XM satellite radio acts like a
normal radio.
For more information on satellite radio
operation, see the separate operating
instructions.
You can only change the waveband and store
new stations using COMAND.
XSwitch on COMAND and select Radio (see
the separate operating instructions).XPress the V or U button on the
steering wheel to select the Audio menu.:Waveband 24;Current stationXTo select a stored station:
briefly press
the & or * button.XTo select a station from the station
list: press and briefly hold the & or
* button.XTo select a station using station
search 25
: press and briefly hold the &
or * button.
Operating audio player or audio media
Audio data from various audio devices or
media can be played, depending on the
equipment installed in the vehicle.
XSwitch on COMAND and select the audio
device or medium (see the separate
operating instructions).XPress the V or U button on the
steering wheel to select the Audio menu.
CD changer display (example)
:Current CD;Current track24
If current station ; has been stored, the memory position will also be displayed.
25 Only if no station list is received.Menus and submenus203On-board computer and displaysZ

Settings menu
Introduction
The Settings menu can be used for:
R restoring the factory settings
R changing the instrument cluster settings
R changing the time/date settings 26
R changing the light settings
R changing the vehicle settings
R changing the convenience settings
Resetting to factory settings
For safety reasons, the Daytime Running
Lamps function in the Lighting submenu is
only reset when the engine is switched off.
XPress V or U on the steering wheel
to select the Settings menu.XPress and hold the . reset button on the
instrument cluster for approximately three
seconds.
A prompt appears in the multifunction
display asking you to confirm by pressing
the . reset button again.XPress the . reset button again.
The settings of most functions are restored
to the factory settings.
or
XIf you want to retain the settings, do not
press the . reset button a second time.
After approximately five seconds, the
Settings menu reappears.XPress the V or U button to select a
different menu.Instrument cluster
Selecting the unit of measurement for
distance
This function is only available in Canada.
The Display unit Speedometer/
Odometer function allows you to choose
whether certain displays appear in kilometers
or miles.
The selected unit of measurement for
distance applies to:
R the analog speedometer
R the odometer and the trip odometer
R the trip computer
R the navigation instruction in the
Navigation menu
R DISTRONIC
XPress the V or U button on the
steering wheel to select the Settings
menu.XPress the & button to call up the
selection of submenus.XPress the W or X button to select the
Instrument Cluster submenu.XPress the & button to select Display
Unit Speedometer/Odometer .XPress the W or X button to select
km or Miles as the unit of measurement for
distance.XPress the &, V or U button to
select a different display.
Selecting the unit of distance for the
digital speedometer
XPress V or U on the steering wheel
to select the Settings menu.XPress the & button to select submenus.XPress the W or X button to select the
Instrument cluster submenu.XPress the & button to display Display
unit Digital speedometer .26
This function is not available in vehicles with the navigation module.Menus and submenus205On-board computer and displaysZ

XPress the W or X button to select
km or miles as the unit of measurement for
distance.XPress the &, V or U button to
select a different display.
Selecting the language
The Language: function allows you to select
the language for the instrument cluster.
XPress V or U on the steering wheel
to select the Settings menu.XPress the & button to select submenus.XPress W or X to select the
Instrument cluster submenu.XPress & to select Language .XPress the W or X button to select the
desired language.XPress the &, V or U button to
select a different display.
Selecting the status line display
XPress V or U on the steering wheel
to select the Settings menu.XPress the & button to select submenus.XPress W or X to select the
Instrument cluster submenu.XPress & to select Status line
display .XPress W or X to select the display in
the status line: speed ( Speed) or outside
temperature ( Outside temp. ).
The selected display now appears
constantly in the lower multifunction
display. When you scroll through the
Standard display menu (Y page 202), you
will see the display you have not selected.XPress the &, V or U button to
select a different display.
Time/date
This submenu is only available on vehicles
with no navigation module. To set the time
and the date for vehicles with a navigation
module, see the separate operating
instructions.
In the Time/date submenu, you can set the
time and date.XPress V or U on the steering wheel
to select the Settings... menu.XPress the & button to select submenus.XPress the W or X button to select the
Time/date submenu.XTo set the time: press & to select
Clock Set Hour or Clock Set
Minute(s) .
or
XTo set the date: press & to select
Date Set Day , Date Set Month or Date
Set Year .XPress W or X to set a value.XPress the &, V or U button to
select a different display.
Lights
Switching the daytime running lamps on/
off
This function is not available in Canada.
If you have activated the Daytime Running
Lights function and the light switch is in the
$ or à position, the daytime running
lamps are automatically switched on when
the engine is running.
In the dark, the following also light up:
R the low-beam headlamps
R the parking lamps
R the tail lamps
R the license plate lamp
R the side marker lamps
On vehicles with daytime running lamps, the
factory setting is On
XSwitch off the engine.XPress V or U on the steering wheel
to select the Settings menu.XPress the & button to select submenus.206Menus and submenusOn-board computer and displays