parking brake MERCEDES-BENZ R-Class 2012 W251 Service Manual

Display messagesPossible causes/consequences and M Solutionsh
Tire Pressure
Check TiresGRisk of accident
The tire pressure in one or more tires has dropped significantly.
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).XCheck the tire pressure. If necessary, correct the tire pressure
( Y page 331).h
Please correct the
tire pressuresThe 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).
Vehicle
Display messagesPossible causes/consequences and M SolutionsShift to P or N
to start engine.You have attempted to start the engine with the transmission in
position R or D.XShift the transmission to position P or N.Auxiliary Battery
MalfunctionThe auxiliary battery for the automatic transmission is no longer
being charged.XVisit a qualified specialist workshop at the next opportunity.XUntil then, set the automatic transmission to position P before
you switch off the engine.XBefore leaving the vehicle, apply the parking brake.Depress brake to
shift out of P.You have attempted to move the transmission selector lever to
position D, R or N without depressing the brake pedal.XDepress the brake pedal.Door Open
Vehicle Not In ParkThe driver's door is open and the transmission is in position R, N
or D.XShift the transmission to position P.XEngage the parking brake.234Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsDrive to workshop
without shifting
gears.You cannot change the transmission position due to a malfunction.
If transmission position D is selected:XDrive to a qualified specialist workshop without shifting the
transmission from position D.
If transmission position R, N or P is selected:
XNotify a qualified specialist workshop or breakdown service.Only shift to P
when vehicle is at
a standstill.The vehicle is moving.XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XShift the transmission to position P.EGRisk of accident
The hood or the tailgate is open.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XEngage the parking brake.XClose the hood or tailgate.You have attempted to lock the vehicle with KEYLESS-GO while
the tailgate or door is open.XClose all the doors and/or the tailgate.;At least one door is open.XClose all the doors.D
Power Steering
Malfunction See
Operator's ManualGRisk of accident
The power steering assistance is defective.
You will need to use more force to steer.
XCheck whether you are able to apply the extra force required.XIf you are able to steer safely: carefully drive on to a qualified
specialist workshop.XIf you are unable to steer safely: do not drive on. Contact the
nearest qualified specialist workshop.No ServiceYour vehicle is outside the network provider's transmitter/
receiver range.XWait until the mobile phone operational readiness symbol
appears in the multifunction display.Display messages235On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutions+
Key Not Detected
(Red display message)The KEYLESS-GO key is not in the vehicle.
If the engine is switched off, you can no longer lock the vehicle
centrally or start the engine.XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XEngage the parking brake.XLocate the KEYLESS-GO key.The KEYLESS-GO key is not detected while the engine is running
because there is interference from a strong source of radio waves.XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XEngage the parking brake.XOperate the vehicle with the SmartKey in the ignition lock.+
Key Not Detected
(White display
message)The KEYLESS-GO key cannot be detected at present.XChange the location of the key with the KEYLESS-GO functions
in the vehicle.
If the KEYLESS-GO key is still not detected:
XChange the location of the key with the KEYLESS-GO functions
in the vehicle.XOperate the vehicle with the SmartKey in the ignition lock.+
Key Detected in
VehicleThe KEYLESS-GO key has been detected inside the vehicle during
locking.XRemove the KEYLESS-GO key from the vehicle.+
Pull starting
button out then
insert key.The KEYLESS-GO key can continuously not be detected.XInsert the SmartKey into the ignition lock and turn it to the
desired position.XVisit a qualified specialist workshop.Display messages237On-board computer and displaysZ

ProblemPossible causes/consequences and M Solutions7
The red seat belt
warning lamp flashes
and an intermittent
audible warning
sounds.GRisk of injury
The driver or front passenger has not fastened their seat belt. In
addition, you are driving faster than 15 mph (25 km/h) or you have
briefly driven faster than 15 mph (25 km/h).
XFasten your seat belt ( Y page 51).
The warning lamp goes out and the intermittent warning tone
ceases.GRisk of injury
There are objects on the front-passenger seat. In addition, you are
driving faster than 15 mph (25 km/h) or you have briefly driven
faster than 15 mph (25 km/h).
XRemove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out and the intermittent warning tone
ceases.
Safety systems
ProblemPossible causes/consequences and M Solutions$ (USA only)
J (Canada only)
The red brake system
warning lamp comes on
while the engine is
running. A warning tone
also sounds.GRisk of accident
There is not enough brake fluid in the brake fluid reservoir.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.XEngage the parking brake.XConsult a qualified specialist workshop immediately.XObserve the additional display messages in the multifunction
display.
Do not add brake fluid. This will not correct the malfunction.
GWARNING
Driving with the brake warning lamp illuminated can result in an accident. Have your brake system
checked immediately if the brake warning lamp stays on. Do not add brake fluid before checking
the brake system.
Overfilling the brake fluid reservoir can result in spilling brake fluid on hot engine parts and the
brake fluid catching fire. You can be seriously burned.
Warning and indicator lamps in the instrument cluster239On-board computer and displaysZ

ProblemPossible causes/consequences and M Solutions$ (USA only)
J (Canada only)
The red brake system
warning lamp comes on
while the vehicle is
moving. A warning tone
also sounds.You are driving with the parking brake applied.XRelease the parking brake
The warning lamp goes out and the warning tone ceases.+
The red SRS warning
lamp is lit while the
engine is running.GRisk of injury
The restraint systems are malfunctioning. The air bags or ETDs
may either be triggered unintentionally or, in the event of an
accident, not be triggered at all.
XDrive on carefully.XVisit a qualified specialist workshop immediately.GWARNING
In the event a malfunction of the SRS is indicated as outlined above, the SRS may not be
operational.
For your safety, we strongly recommend that you contact an authorized Mercedes-Benz Center
immediately to have the system checked. Otherwise the SRS may not be activated when needed
in an accident, which could result in serious or fatal injury, or it might deploy unexpectedly and
unnecessarily which could also result in injury.
Warning and indicator lamps in the instrument cluster243On-board computer and displaysZ

XMake sure the vehicle is stationary and the
ignition is switched off.XTurn the SmartKey to position
2 (Y page 145) in the ignition lock.
Use the SmartKey instead of the Start/
Stop button on vehicles with KEYLESS-GO.XDepress and hold the brake pedal.XShift the automatic transmission to
position N.XRelease the brake pedal.XRelease the parking brake.XSwitch off the ignition and leave the
SmartKey in the ignition lock.
! Make sure that:
R the side windows and the sliding sunroof
are fully closed.
R the ventilation/heating is switched off
(the OFF button has been pressed).
R the windshield wiper switch is in position
0 .
Otherwise, the vehicle might be damaged.
After using an automatic car wash, wipe off
wax from the windshield and the wiper
blades. This will prevent smears and reduce
wiping noises caused by residue on the
windshield.
Washing by hand
Carefully remove all deposits of road salt as
soon as possible when driving in winter.
Also, clean the insides of the wheels when
washing the underbody of the vehicle.
XDo not use hot water and do not wash the
vehicle in direct sunlight.XUse a soft car sponge for cleaning.XUse a gentle cleaning agent, e.g. a
Mercedes-Benz approved car shampoo.XWash down the vehicle with a gentle water
jet.XDo not point the water jet directly at the air
inlets.XUse plenty of water and rinse the sponge
frequently.XRinse the vehicle with clean water and dry
it thoroughly with a chamois.XDo not allow the cleaning agent to dry on
the paintwork.
Power washers
GWARNING
Do not use power washers with circular-jet
nozzles (dirt grinders) to clean your vehicle, in
particular the tires. You could otherwise
damage the tires and cause an accident.
! Always maintain a distance of at least
11.8 in (30 cm) between the vehicle and the
power washer nozzle. Information about
the correct distance is available from the
equipment manufacturer.
Move the power washer nozzle around
when cleaning your vehicle.
Do not aim directly at any of the following:
R tires
R door gaps, roof gaps, joints etc.
R electrical components
R battery
R connectors
R lights
R seals
R trim elements
R ventilation slots
Damaged seals or electrical components
can lead to leaks or failures.
Cleaning the wheels
! Do not use acidic wheel cleaning products
to remove brake dust. This could damage
wheel bolts and brake components.
! Do not park the vehicle for an extended
period straight after cleaning it, particularly
after having cleaned the wheels with wheel
cleaner. Wheel cleaners could cause
increased corrosion of the brake discs and
brake pads/linings. For this reason, you
should drive for a few minutes after
Care289Maintenance and careZ

Flat tire
Preparing the vehicle
Your vehicle may be equipped with a
collapsible spare wheel or MOExtended tires
(tires with run-flat properties) ( Y page 309).
i Vehicle preparation is not necessary on
vehicles with MOExtended tires.
i Vehicles equipped with MOExtended tires
are not equipped with a TIREFIT kit at the
factory. It is therefore recommended that
you additionally equip your vehicle with a
TIREFIT kit if you mount tires that do not
feature run-flat properties, e.g. winter tires.
A TIREFIT kit can be obtained from an
authorized Mercedes-Benz Center.
XVehicles with the AIRMATIC package: make
sure that highway level is selected
( Y page 180).XStop the vehicle as far away as possible
from traffic on solid, non-slippery and level
ground.XSwitch on the hazard warning lamps.XFirmly depress the parking brake.XBring the front wheels into the straight-
ahead position.XMove the DIRECT SELECT lever to P.XSwitch off the engine.XVehicles without KEYLESS-GO: remove
the SmartKey from the ignition lock.XVehicles with KEYLESS-GO: open the
driver's door.
The on-board electronics have status 0,
which is the same as the SmartKey having
been removed.XVehicles with KEYLESS-GO: remove the
Start/Stop button from the ignition lock
( Y page 145).XAll occupants must get out of the vehicle.
Make sure that they are not endangered as
they do so.XMake sure that no one is near the danger
area while a wheel is being changed.Anyone who is not directly assisting in the
wheel change should, for example, stand
behind the barrier.XGet out of the vehicle. Pay attention to
traffic conditions when doing so.XClose the driver's door.
i Only operate the tire inflation compressor
using the socket in the footwell of the
second row of seats ( Y page 268), even if
the ignition is turned off.
An emergency cut-off ensures that the on-
board electrical system voltage does not
drop too low. If the on-board electrical
system voltage is too low, power to the
sockets is automatically cut off. This
ensures that there is sufficient power to
start the engine.
TIREFIT kit
Using the TIREFIT kit
You can use the TIREFIT kit to seal small
punctures, particularly those in the tire tread.
You can use TIREFIT at outside temperatures
down to -4 ‡ (-20 †).
GWARNING
TIREFIT is a limited repair device. TIREFIT
cannot be used for cuts or punctures larger
than approximately 0.16 in (4 mm) and tire
damage caused by driving with extremely low
tire inflation pressure, or on a flat tire, or a
damaged wheel.
Do not drive the vehicle under such
circumstances.
Contact the nearest authorized Mercedes-
Benz Center for assistance or call Roadside
Assistance.
XDo not remove any foreign objects which
have penetrated the tire, e.g. screws or
nails.XRemove the tire sealant bottle, the
accompanying "max. 80 km/h" sticker and
the tire inflation compressor from theFlat tire299Breakdown assistanceZ

Securing the vehicle on level ground
XOn level ground: place chocks or other
suitable items under the front and rear of
the wheel that is diagonally opposite the
wheel you wish to change.
Securing the vehicle on slight downhill gradients
XOn downhill gradients: place chocks or
other suitable items in front of the wheels
of the front and rear axle.
Raising the vehicle
GWARNING
When jacking up the vehicle, only use the jack
which has been specifically approved by
Mercedes-Benz for your vehicle.
The jack is designed exclusively for jacking up
the vehicle at the jacking points built into both
sides of the vehicle. The jack saddle must be
placed centrally under the jacking point. The
jack must always be vertical when in use,
especially on inclines or declines.
The jack is intended only for lifting the vehicle
briefly for wheel changes. It is not suited for
performing maintenance work under the
vehicle. To help avoid personal injury, use the
jack only to lift the vehicle during a wheel
change.
Never get beneath the vehicle while it is
supported by the jack. Keep hands and feet
away from the area under the lifted vehicle.
Always lower the vehicle onto sufficient
capacity jackstands before working under the
vehicle.
Always firmly engage the parking brake and
block the wheels with wheel chocks or other
sizable objects before raising the vehicle with
the jack. Do not disengage the parking brake
while the vehicle is raised.
Make sure that the ground on which the
vehicle is standing and where you place the
jack is solid, level and not slippery. If
necessary, use a large underlay. On slippery
surfaces, such as tiled floors, you should use
a non-slip underlay, for example a rubber mat.
Do not use wooden blocks or similar objects
as a jack underlay. Otherwise, the jack may
not be able to achieve its load-bearing
capacity if it is not at its full height.
Never start the engine when the vehicle is
raised.
Also observe the notes on the jack.XUsing lug wrench :, loosen the bolts on
the wheel you wish to change by about one
full turn. Do not unscrew the bolts
completely.
The jacking points for the jack are located
behind the wheel housings of the front wheels
Flat tire305Breakdown assistanceZ

Jump-startingGWARNING
Failure to follow these directions will cause damage to the electronic components, and can lead
to a battery explosion and severe injury or death.
Never lean over batteries while connecting or jump starting. You might get injured.
Battery fluid contains sulfuric acid. Do not allow this fluid to come in contact with eyes, skin or
clothing. In case it does, immediately flush affected area with water, and seek medical help if
necessary.
A battery will also produce hydrogen gas, which is flammable and explosive. Keep flames or
sparks away from battery, avoid improper connection of jumper cables, smoking, etc.
Attempting to jump start a frozen battery can result in it exploding, causing personal injury.
Read all instructions before proceeding.
! Avoid repeated and lengthy starting attempts. Otherwise, non-combusted fuel may
damage the catalytic converter 36
and create a risk of fire.
Do not use a rapid-charging device to start the engine.
Make sure the jumper cables are not damaged.
Make sure the jumper cables are not touching any other metal objects when they are
connected to the battery.
If your vehicle's battery is discharged, the engine can be jump-started from another vehicle
or from a second battery using jumper cables.
Observe the following points:
XThe battery is not accessible in all vehicles. If the other vehicle's battery is not accessible,
jump-start the vehicle using a second battery or a jump-starting device.XOnly jump-start the vehicle when the engine is cold and the catalytic converter system has
cooled down 37
.XDo not start the engine if the battery is frozen. Let the battery thaw first.XJump-starting may only be performed from batteries with a nominal voltage of 12 V.XOnly use jumper cables which have a sufficient cross-section and insulated terminal clamps.XMake sure that the jumper cables cannot come into contact with parts, such as the pulley
or the fan. These parts move when the engine is started and while it is running.XIf the battery is fully discharged, leave the battery that is being used to jump-start connected
for a few minutes before attempting to start. This charges the empty battery a little.
i Jumper cables and further information about jump-starting can be obtained from any
authorized Mercedes-Benz Center, for example.
XMake sure that the two vehicles do not touch.XApply the parking brake firmly.XShift the transmission to position P.36
Only vehicles with a gasoline engine.
37 Only vehicles with a gasoline engine.Jump-starting313Breakdown assistanceZ

XPress the mark on cover : inwards in the
direction of the arrow.XTake cover : off the opening.XScrew the towing eye in clockwise to the
stop and tighten it.
Removing the towing eye
XLoosen the towing eye and unscrew it.XAttach cover : to the bumper and press
until it engages.XPlace the towing eye in the vehicle tool kit.
Towing a vehicle with both axles on
the ground
When having your vehicle towed, observe the
important safety notes ( Y page 315).
GWARNING
The power assistance for the steering and the
brake force booster do not work when the
engine is not running. You will then need
much more effort to brake and steer the
vehicle. Adapt your style of driving
accordingly.
The automatic transmission automatically
shifts to position P when you open the driver's
or front-passenger door or when you remove
the SmartKey from the ignition lock. In order
to ensure that the automatic transmission
stays in position N when towing the vehicle,
you must observe the following points:XMake sure that the vehicle is stationary and
the SmartKey in the ignition lock is in
position 0.XTurn the SmartKey to position 2 in the
ignition lock.
On vehicles with KEYLESS-GO, use the key
instead of the Start/Stop button
( Y page 145).XDepress and hold the brake pedal.XShift the automatic transmission to
position N.XRelease the brake pedal.XRelease the parking brake.XLeave the SmartKey in position 2 in the
ignition lock.
Transporting the vehicle
The towing eyes or trailer tow hitch can be
used to pull the vehicle onto a trailer or
transporter if you wish to transport it.
XTurn the SmartKey to position 2 in the
ignition lock.XShift the automatic transmission to
position N.
As soon as the vehicle is loaded:
XPrevent the vehicle from rolling away by
applying the parking brake.XShift the automatic transmission to
position P.XTurn the SmartKey to position 0 in the
ignition lock and remove the SmartKey
from the ignition lock.XSecure the vehicle.
! Only lash the vehicle down by the wheels
or wheel rims, not by parts of the vehicle
316Towing and tow-startingBreakdown assistance