stop start MERCEDES-BENZ R-Class 2012 W251 Owner's Guide

Using KEYLESS-GO to start the engineGWARNING
As long as the SmartKey is in your vehicle, the
vehicle can be started. Therefore, never leave
children unattended in the vehicle, as they
could otherwise accidentally start the engine.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Do
not leave children unattended in the vehicle,
or with access to an unlocked vehicle. A
child's unsupervised access to a vehicle could
result in an accident and/or serious personal
injury.
i The Start/Stop button can be used to
start the vehicle without inserting the
SmartKey into the ignition lock. The Start/
Stop button must be inserted into the
ignition lock and the SmartKey must be in
the vehicle.
XDepress the brake pedal and keep it
depressed.XTo start a gasoline engine: press the
Start/Stop button ( Y page 145) once.
The engine starts.XTo start a diesel engine: press the Start/
Stop button ( Y page 145) once.
Preglow is activated and the engine starts.
i If the engine is warm, the preglow time is
shortened.
Pulling away
Automatic transmission
GWARNING
It is dangerous to shift the automatic
transmission out of parking position P or
neutral position N if the engine speed is
higher than idle speed. If your foot is not firmly
on the brake pedal, the vehicle could
accelerate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and when
your right foot is firmly on the brake pedal.
i It is only possible to shift the transmission
from position P to the desired position if
you depress the brake pedal. Only then is
the parking lock released. If you do not
depress the brake pedal, you can move the
DIRECT SELECT lever but the parking lock
remains engaged.XDepress the brake pedal and keep it
depressed.XShift the transmission to position D or R.XRelease the parking brake ( Y page 164).XRelease the brake pedal.XCarefully depress the accelerator pedal.
!
If a warning tone sounds and the
Release Park. Brake message appears
in the multifunction display, the parking
brake is still applied. Release the parking
brake.
i The vehicle locks centrally once you have
pulled away. The locking knobs in the doors
drop down.
You can open the doors from the inside at
any time.
You can also deactivate the automatic
locking feature ( Y page 208).
i Upshifts take place at higher engine
speeds after a cold start. This helps the
catalytic converter to reach its operating
temperature more quickly.
Hill start assist
Hill start assist helps you when pulling away
forwards or in reverse on an uphill gradient.
It holds the vehicle for a short time after you
have removed your foot from the brake pedal.
This gives you enough time to move your foot
from the brake pedal to the accelerator pedal
and depress it before the vehicle begins to
roll.
Driving147Driving and parkingZ

Problems with the engineProblemPossible causes/consequences and M SolutionsThe engine does not
start. The starter motor
can be heard.R There is a malfunction in the engine electronics.
R There is a malfunction in the fuel supply.XBefore attempting to start the engine again, turn the SmartKey
in the ignition back to position 0 or press the Start/Stop button
repeatedly until all indicator lamps in the instrument cluster go
out.XTry to start the engine again ( Y page 146). Avoid excessively
long and frequent attempts to start the engine as these will drain
the battery.
If the engine does not start after several attempts:
XConsult a qualified specialist workshop, e.g. an authorized
Mercedes-Benz Center.The engine does not
start. You cannot hear
the starter motor.The on-board voltage is too low because the battery is too weak
or discharged.XJump-start the vehicle ( Y page 313).
If the engine does not start despite attempts to jump-start it:
XConsult a qualified specialist workshop, e.g. an authorized
Mercedes-Benz Center.The starter motor was exposed to a thermal load that was too high.XAllow the starter motor to cool down for approximately two
minutes.XTry to start the engine again.
If the engine still does not start:
XConsult a qualified specialist workshop, e.g. an authorized
Mercedes-Benz Center.Driving149Driving and parkingZ

Engaging park position PXPush the DIRECT SELECT lever in the
direction of arrow P.
i
The automatic transmission shifts
automatically into park position P if you
open the driver's door when the vehicle is
stationary or driving at very low speed, and
the transmission is in position D or R.
! If the engine speed is too high or the
vehicle is moving, do not shift the
automatic transmission directly from D to
R , from R to D or directly to P. The
automatic transmission could otherwise be
damaged.
Engaging reverse gear R
! Only shift the automatic transmission to
R when the vehicle is stationary.
XWhen the vehicle is stationary, depress the
brake pedal.XPush the DIRECT SELECT lever up past the
first point of resistance.
Shifting to neutral N
XWhen the vehicle is stationary, depress the
brake pedal.XPush the DIRECT SELECT lever up or down
to the first point of resistance.
If the engine has been switched off, the
automatic transmission automatically
switches to N.
Remaining in neutral N
If the automatic transmission is to remain in
neutral N, e.g. for washing the vehicle in car
washes with a towing device, please observe
the following instructions:
GWARNING
When leaving the SmartKey in the starter
switch, do not leave children unattended in
the vehicle. It is possible for children to switch
on the ignition which could result in
unsupervised use of vehicle equipment.
Unsupervised use of vehicle equipment could
result in an accident and/or serious personal
injury.
Using the SmartKey:
R make sure that the ignition is switched on.
R when the vehicle is stationary, depress the
brake pedal and keep it depressed.
R shift to neutral N.
R release the brake pedal.
R if applied, release the parking brake.
R switch off the ignition and leave the
SmartKey in the ignition lock.
Using KEYLESS-GO:
R make sure that the ignition is switched on.
R when the vehicle is stationary, depress the
brake pedal and keep it depressed.
R engage park position P.
R release the brake pedal.
R remove the Start/Stop button from the
ignition lock.
R insert the SmartKey into the ignition lock.
R switch on the ignition.
R depress the brake pedal and keep it
depressed.
R shift to neutral N.
R release the brake pedal.
R if applied, release the parking brake.
R switch off the ignition and leave the
SmartKey in the ignition lock.
Shifting to transmission position DXWhen the vehicle is stationary, depress the
brake pedal.XPush the DIRECT SELECT lever down past
the first point of resistance.
Transmission position display
The current transmission position is shown in
the multifunction display.
Automatic transmission151Driving and parkingZ

Problems with the transmissionProblemPossible causes/consequences and M SolutionsThe transmission has
problems shifting gear.The transmission is losing oil.XHave the transmission checked at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz Center,
immediately.The acceleration ability
is deteriorating.
The transmission no
longer changes gear.The transmission is in emergency mode.
It is only possible to shift into second gear and reverse gear.XStop the vehicle.XShift the transmission to position P.XSwitch off the engine.XWait at least 10 seconds before restarting the engine.XShift the transmission to position D or R.
If D is selected, the transmission shifts into second gear; if R is
selected, the transmission shifts into reverse gear.XHave the transmission checked at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz Center,
immediately.Transfer case
The vehicle has permanent 4-wheel drive
(4MATIC). Power is always transmitted to
both axles.
! Performance tests may only be carried
out on a 2-axle dynamometer. The brake
system or transfer case could otherwise be
damaged. Contact a qualified specialist
workshop for a performance test.
Mercedes-Benz recommends that you use
an authorized Mercedes-Benz Center for
this purpose.
! If the parking brake is being tested on a
brake dynamometer, the ignition must be
switched off (SmartKey or Start/Stop
button in position 0 or 1), as ESP ®
will
otherwise automatically intervene. The test
must last a maximum of 10 seconds. The
brake system could otherwise be damaged.Refueling
Important safety notes
GWARNING
Gasoline and diesel fuels are highly flammable
and poisonous. They burn violently and can
cause serious injury.
Never allow sparks, flames or smoking
materials near gasoline or diesel fuel!
Turn off the engine before refueling.
Whenever you are around gasoline or diesel
fuel, avoid inhaling fumes and any skin or
clothing contact. Extinguish all smoking
materials.
Direct skin contact with fuels and the
inhalation of fuel vapors are damaging your
health.
GWARNING
Overfilling of the fuel tank may create
pressure in the system which could cause a
gas discharge. This could cause the gasoline
156RefuelingDriving and parking

XInsert DEF cap : as shown and turn it
clockwise as far as it will go.XStow lug wrench ; and ratchet wrench
= again.XFold the cargo compartment floor down.XClose the tailgate.XDrive at a speed above 10 mph (16 km/h).
The Check Additive See Operator's
Manual message goes out after
approximately one minute.
i If the Check Additive See
Operator's Manual message remains
shown in the multifunction display, add an
additional bottle of DEF.
i Then, have the DEF supply checked at a
qualified specialist workshop and
completely refilled if necessary.
Parking
Important safety notes
GWARNING
Do not park this vehicle in areas where
combustible materials can come into contact
with the hot exhaust system. Do not park the
vehicle on dry grassland or harvested grain
fields. Combustible materials, such as grass,
hay or leaves could be ignited by the hot
exhaust system and cause a vehicle fire.
Unintended vehicle movement can cause
serious personal injury or damage to the
vehicle or the vehicle drivetrain. To reduce
such risks, always do the following before
turning off the engine and leaving the vehicle:
R keep your right foot on the brake pedal.
R engage the parking brake.
R shift the automatic transmission to park
position P.
R slowly release the brake pedal.
R when parked on an incline, always turn the
front wheels towards the road curb.
R turn the SmartKey in the ignition lock to
position 0 and remove the SmartKey from
the ignition lock, or press the KEYLESS-GO
Start/Stop button.
R take the SmartKey with you and lock the
vehicle when leaving.
Switching off the engine
Important safety notes
GWARNING
Do not turn off the engine before the vehicle
has come to a complete stop. With the engine
not running, there is no power assistance for
the brake and steering systems. In this case,
it is important to keep in mind that a
considerably higher degree of effort is
necessary to brake and steer the vehicle.
GWARNING
Keep in mind that turning off the engine alone
only will shift the automatic transmission into
neutral position N automatically.
Always shift the automatic transmission into
park position P before turning off the engine.
Otherwise the vehicle could roll away which
could result in an accident and/or serious
personal injury.
i If you cannot turn off the engine as
described here, see "Engine emergency
stop" ( Y page 319).
Vehicles with automatic transmission
XApply the parking brake firmly.XShift the transmission to position P.
Using the SmartKey
XTurn the SmartKey to position 0 in the
ignition lock and remove it.
The immobilizer is activated.
i If you turn off the engine with the
SmartKey and then remove it from the
ignition lock or open a front door, the
Parking163Driving and parkingZ

automatic transmission shifts to P
automatically.
Using KEYLESS-GOXPress the Start/Stop button (Y page 145).
The engine stops and all the indicator
lamps in the instrument cluster go out.
i When the driver's door is closed, this
corresponds to SmartKey position 1. When
the driver's door is open, it corresponds to
SmartKey position 0 or "SmartKey
removed".
i If you use the Start/Stop button to switch
off the engine, the automatic transmission
shifts to N automatically. If you then open
the driver's or front-passenger door, the
automatic transmission shifts to P.
i In an emergency, the engine can be
turned off while the vehicle is in motion by
pressing and holding the Start/Stop button
for three seconds.
Parking brake
GWARNING
Engaging the parking brake while the vehicle
is in motion can cause the rear wheels to lock
up. You could lose control of the vehicle and
cause an accident. In addition, the vehicle's
brake lights do not light up when the parking
brake is engaged.
GWARNING
When leaving the vehicle, always remove the
SmartKey from the starter switch, take it with
you, and lock the vehicle. Do not leave
children unattended in the vehicle, or with
access to an unlocked vehicle. Children could
release the parking brake and/or shift the
automatic transmission out of park position
P , either of which could result in an accident
and/or serious personal injury.
XTo apply: depress parking brake ; firmly.
When the engine is running, the $ (USA
only) or J (Canada only) indicator lamp
lights up in the instrument cluster.XTo release: depress the brake pedal and
keep it depressed.XPull release handle :.
When the ignition is switched on or the
engine is running, the $ (USA only) or
J (Canada only) indicator lamp goes out
in the instrument cluster.
Parking the vehicle for a long period
If you leave the vehicle parked for longer than
four weeks, the battery may be damaged by
exhaustive discharge.
XConnect a trickle charger.
i You can obtain information about trickle
chargers from a qualified specialist
workshop, e.g. an authorized Mercedes-
Benz Center.
If you leave the vehicle parked for longer than
six weeks, the vehicle may suffer damage as
a result of lack of use.
XVisit a qualified specialist workshop and
seek advice.164ParkingDriving and parking

Wet roadsGWARNING
After driving in heavy rain for some time
without applying the brakes or through water
deep enough to wet brake components, the
first braking action may be somewhat
reduced. You have to depress the brake pedal
more firmly. Maintain a safe distance from
vehicles in front.
After driving on a wet road or having the
vehicle washed, brake firmly while paying
attention to the traffic conditions. This will
warm up the brake discs, thereby drying them
more quickly and protecting them against
corrosion.
Limited braking performance on salt
treated roads
GWARNING
The layer of salt on the brake discs and the
brake pads/linings may cause a delay in the
braking effect, resulting in a significantly
longer braking distance, which could lead to
an accident.
To avoid this danger, you should:
R occasionally brake carefully, without
putting other road users at risk, when you
are driving on salted roads. This helps to
remove any salt that may have started to
build up on the brake discs and the brake
pads/linings.
R maintain a greater distance to the vehicle
ahead and drive with particular care.
R carefully apply the brakes at the end of a
trip and immediately after commencing a
new trip, so that salt residues are removed
from the brake discs.
Servicing the brakes
! If the brake warning lamp lights up in the
instrument cluster and you hear a warning
tone even though the parking brake has
been released, the brake fluid level may be
too low. Observe additional warning
messages in the multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked
immediately. Have this work carried out at
an authorized Mercedes-Benz Center.
All checks and maintenance work on the
brake system must be carried out at a
qualified specialist workshop. This work
should be carried out at an authorized
Mercedes-Benz Center.
Have the brake pads and brake fluid installed
or replaced at a qualified specialist workshop,
e.g. an authorized Mercedes-Benz Center.GWARNING
If other than recommended brake pads are
installed, or other than recommended brake
fluid is used, the braking properties of the
vehicle can be degraded to an extent that safe
braking is substantially impaired. This could
result in an accident.
! A function or performance test should
only be carried out on a 2-axle
dynamometer. If you are planning to have
the vehicle tested on such a dynamometer,
contact an authorized Mercedes-Benz
Center to obtain further information first.
Otherwise, you could damage the drive
train or the brake system.
! As the ESP ®
system operates
automatically, the engine and the ignition
must be switched off (SmartKey in position
0 or 1 in the ignition lock or Start/Stop
button in position 0 or 1) while the parking
brake is being tested on a brake
dynamometer (maximum 10 seconds).
Braking maneuvers triggered automatically
by ESP ®
may seriously damage the brake
system.
If your brake system is subject only to
moderate loads, you should test the
functionality of your brakes at regular
intervals by pressing firmly on the brake pedal
Driving tips167Driving and parkingZ

Display messagesPossible causes/consequences and M Solutions?
Coolant Stop car,
switch engine offThe coolant is too hot.XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.XMake sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.XWait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.XPay attention to the coolant temperature display.XIf the temperature increases again, visit a qualified specialist
workshop immediately.The poly-V-belt may have torn.XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.XOpen the hood.XCheck whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise overheat.
XConsult a qualified specialist workshop.
If the poly-V-belt is OK:
XWait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.XPay attention to the coolant temperature display.XVisit a qualified specialist workshop.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.
! If the coolant temperature exceeds 248 ‡(120 †) do not continue driving. The engine will
otherwise be damaged.
226Display messagesOn-board computer and displays

Do not overinflate tires. Overinflated tires can adversely affect handling and ride comfort, wear
unevenly, increase stopping distance, and result in sudden deflation (blowout) because they are
more likely to become punctured or damaged by road debris, potholes etc.Display messagesPossible causes/consequences and M SolutionsTire Pressure
Check TiresGRisk of accident
The tire pressure loss warning system has detected a significant
loss in pressure.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XCheck the tires and, if necessary, change the wheel
( Y page 346).XCheck the tire pressures and, if necessary, set to the correct
tire pressure.XRestart the tire pressure loss warning system when the tire
pressure is correct ( Y page 329).Check tires,
then restart Run
Flat IndicatorThe tire pressure loss warning system generated a display
message and has not been restarted since.XSet the correct tire pressure in all four tires.XRestart the tire pressure loss warning system ( Y page 329).Run Flat Indicator
InoperativeThe tire pressure loss warning system is defective.XVisit a qualified specialist workshop.Tire pressure
displayed after
driving for a few
minutesThe tire pressure monitor is measuring the tire pressure.XDrive on.
The tire pressures appear in the multifunction display after you
have been driving for a few minutes.Tire Pressure
Monitor
InoperativeThe tire pressure monitor is defective.XVisit a qualified specialist workshop.Tire Pressure
Monitor
Inoperative No
Wheel SensorsThe wheels mounted do not have a suitable tire pressure sensor.
The tire pressure monitor is deactivated.XMount wheels with suitable tire pressure sensors.
The tire pressure monitor is activated automatically after driving
for a few minutes.232Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsCheck
Tire(s)GRisk of accident
The tire pressure in one or more tires has dropped significantly.
The wheel position is displayed in the multifunction display.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XCorrect the tire pressure ( Y page 331).XIf necessary, change a wheel ( Y page 346).Caution:
Tire DefectGRisk of accident
The tire pressure in one or more tires has dropped suddenly. The
wheel position is displayed in the multifunction display.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XIf necessary, change a wheel ( Y page 346).Tire Pressure(s)
Please CorrectThe tire pressure is too low in at least one of the tires or the tire
pressure difference between the wheels is too great.XCheck the tire pressures at the next opportunity. If necessary,
correct the tire pressure ( Y page 331).XRestart the tire pressure monitor ( Y page 333).Tire Pressure
Monitor
Wheel Sensor
MissingThere is no signal from the tire pressure sensor of one or several
wheels. The pressure of the affected tire is not displayed in the
multifunction display.XHave the defective tire pressure sensor replaced at a qualified
specialist workshop.Tire Pressure
Monitor
Currently
UnavailableDue to a source of radio interference, no signals can be received
from the wheel sensors. The tire pressure monitor is temporarily
malfunctioning.XDrive on.
The tire pressure monitor restarts automatically as soon as the
problem has been solved.h
Tire Pressure
Caution: Tire
DefectGRisk of accident
The tire pressure in one or more tires has dropped suddenly.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XIf necessary, change a wheel ( Y page 346).Display messages233On-board computer and displaysZ