open hood MERCEDES-BENZ S-Class 2012 W221 User Guide

Display messagesPossible causes/consequences and M Solutions?
Coolant Low Stop
Vehicle Turn
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 not damaged:
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.
Display messages405On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutions?The engine fan is defective.XAt coolant temperatures under 248 ‡ (120 † ), drive to the next
qualified specialist workshop.XAvoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic.#The battery is not being charged.
Possible causes are:
R a defective alternator
R a torn poly-V-belt
R a malfunction in the electronicsXPull 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 not damaged:
XVisit a qualified specialist workshop.4
Check Engine Oil
at Next RefuelingVehicles with an oil dipstick: the oil level has dropped to the
minimum level.XCheck the engine oil level at the latest when next refueling
( Y page 457).XIf necessary, add engine oil ( Y page 459).XIf engine oil needs to be added more often than usual, have the
engine checked at a qualified specialist workshop.4
Check Engine Oil
Level (Add 1 quart)
(USA only) Check
Engine Oil Level
(Add 1 Liter)
(Canada only)Vehicles without an oil dipstick: the engine oil level is too low.XCheck the oil level ( Y page 457).XIf necessary, add engine oil ( Y page 457).XIf engine oil needs to be added more often than usual, have the
engine checked at a qualified specialist workshop.
Information on approved engine oils can be obtained from any qualified specialist workshop
or on the Internet at http://www.mbusa.com (USA only).
406Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsService Required
Do Not Shift GearsYou cannot change the transmission position due to a malfunction.
A warning tone also sounds.
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
Position P When
Vehicle Is
StationaryThe 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.NThe trunk lid is open.XClose the trunk lid.MGRisk of accident
The hood is open.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XApply the electric parking brake.XClose the hood.CAt least one door is open.XClose all the doors.D
Power Steering
Malfunction See
Oper. ManualGRisk of accident
The power steering is malfunctioning.
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.¥
Check Washer FluidThe washer fluid level in the washer fluid reservoir has dropped
below the minimum.XAdd washer fluid ( Y page 461).418Display messagesOn-board computer and displays

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 31).
Engine compartment
Hood
Opening the hood
GWARNING
Do not pull the release lever while the vehicle
is in motion. Otherwise, the hood could be
forced open by passing air flow.
This could cause the hood to come loose and
injure you and/or others.
GWARNING
Hybrid vehicles: be sure to read the "HYBRID"
supplement. Otherwise, you could fail to
recognize dangers.
GWARNING
Do not open the hood when the engine is
overheated. You could be seriously injured.
Observe the coolant temperature gauge to
determine whether the engine may be
overheated. If you see flames or smoke
coming from the engine compartment, move
away from the vehicle. Wait until the engine
has cooled. If necessary, call the fire
department.
GWARNING
There is a risk of injury if the hood is open,
even if the engine is not running.
Some engine components can become very
hot.
To avoid the risk of burns, only touch those
components described in the Operator's
Manual and observe the relevant safety notes.GWARNING
To help prevent personal injury, stay clear of
moving parts when the hood is open and the
engine is running.
The radiator fan may continue to run for
approximately 30 seconds or may even
restart after the engine has been turned off.
Stay clear of fan blades.
GWARNING
Vehicles with gasoline engine:
The engine is equipped with a transistorized
ignition system. Because of the high voltage
it is dangerous to touch any components
(ignition coils, spark plug sockets, diagnostic
socket) of the ignition system
R with the engine running
R while starting the engine
R when the ignition is switched on and the
engine is turned manually
GWARNING
Vehicles with diesel engine:
The engine is equipped with a high-voltage
electronic control unit for the injection
system. Because of the high voltage it is
dangerous to touch any components of the
injection system (injectors, electrical wires)
R with the engine running
R while starting the engine
R when the ignition is switched on
XMake sure that the windshield wipers are
switched off.GWARNING
The windshield wipers and wiper linkage
could be set in motion.
456Engine compartmentMaintenance and care

When the hood is open, you or others could
be injured by the wiper linkage.
Make sure that the windshield wipers are
switched off. Remove the SmartKey or make
sure that no ignition position has been
selected with KEYLESS-GO. All indicator
lamps must be off in the instrument cluster.XPull release lever : for the hood.
The hood is released.
! Make sure that the windshield wipers are
not folded away from the windshield. You
could otherwise damage the windshield
wipers or the hood.
XPull hood catch handle ; outwards from
the radiator grill as far as it will go and lift
the hood from underneath by the radiator
grill.
Once you have lifted the hood about
15 inches (40 cm), it is automatically
opened the rest of the way and held open
by the gas-filled struts.! Do not lift the hood by hood catch
handle ;. The handle may otherwise be
damaged.
Closing the hoodGWARNING
When closing the hood, use extreme caution
not to catch hands or fingers. Be careful that
you do not close the hood on anyone.
Make sure the hood is securely engaged
before driving off. Do not continue driving if
the hood can no longer engage after an
accident, for example. The hood could
otherwise come loose while the vehicle is in
motion and injure you and/or others.
XLower the hood and let it fall from a height
of approximately 8 inches (20 cm).XCheck that the hood has engaged properly.
If the hood can be raised slightly, it is not
properly engaged. Open it again and close
it with a little more force.
Radiator
i Vehicles with a diesel engine: do not
cover the radiator, for example with a
winter front or bug cover. Otherwise, the
readings of the on-board-diagnostic
system may be inaccurate. Some of these
readings are required by law and must be
accurate at all times.
Engine oil
Notes on the oil level
GWARNING
Hybrid vehicles: ensure that you read the
"HYBRID" supplement. You may otherwise fail
to recognize dangers.
Depending on the driving style, the vehicle
consumes up to 0.9 US qts. (0.8 l) of oil over
a distance of 600 miles (1000 km). The oil
Engine compartment457Maintenance and careZ

XTurn cap : counterclockwise and remove
it.XAdd engine oil.
Vehicles with oil level measurement
function in the on-board computer: observe
the information in the on-board computer
when doing so. Vehicles with oil dipstick: if
the oil level is at or below the MIN mark on
the oil dipstick,
add 0.55 to 1.1 US qt (0.5 to 1.0 l) engine
oil.XReplace cap : on the filler neck and turn
clockwise.
Ensure that the cap locks into place
securely.XCheck the oil level again with the oil
dipstick ( Y page 458) or the on-board
computer ( Y page 458).
Further information on engine oil
( Y page 527).
Checking and adding other service
products
Checking the coolant level
Only check the coolant level when the vehicle
is on a level surface and the engine has cooled
down.
XTurn the SmartKey to position
2 (Y page 303) in the ignition lock.
On vehicles with KEYLESS-GO, press the
Start/Stop button twice ( Y page 303).XCheck the coolant temperature display in
the instrument cluster.
The coolant temperature must be below
158 ‡ (70 †).GWARNING
In order to avoid any potentially serious burns:
R use extreme caution when opening the
hood if there are any signs of steam or
coolant leaking from the cooling system, or
if the coolant temperature display indicates
that the coolant is overheated.
R do not remove the pressure cap on the
coolant reservoir if the coolant temperature
is above 158 ‡ (70 †). Allow the engine to
cool down before removing the cap. The
coolant reservoir contains hot fluid and is
under pressure.
R using a rag, slowly turn the cap
approximately 1
/ 2 turn to relieve excess
pressure. If opened immediately, scalding
hot fluid and steam will be blown out under
pressure.
R do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts.XSlowly turn cap : half a turn counter-
clockwise and allow excess pressure to
escape.XTurn cap : further counter-clockwise and
remove it.
If the coolant is at the level of marker bar
= in the filler neck when cold, there is
enough coolant in coolant expansion
tank ;.
If the coolant is approximately 0.6 in
(1.5 cm) above marker bar = in the filler
neck when warm, there is enough coolant
in coolant expansion tank ;.460Engine compartmentMaintenance and care

! Like other batteries, the vehicle battery
may discharge over time if you do not use
the vehicle. In this case have the battery
checked at a qualified specialist workshop,
such as an authorized Mercedes-Benz
Center. You can also charge the battery
with a charger recommended by Mercedes-
Benz. Contact an authorized Mercedes-
Benz Center for more information.
The battery and the cover of the positive
terminal clamp must be installed securely
during operation.
i Remove the SmartKey if you park the
vehicle and do not require any electrical
consumers. The vehicle will then use very
little energy, thus conserving battery
power.
Mercedes-Benz recommends that you do not
carry out work on batteries yourself, e.g.
removing or charging. Always have this work
performed at a qualified specialist workshop,
e.g. an authorized Mercedes-Benz Center.
Charging the battery
GWARNING
Never charge a battery still installed in the
vehicle unless a battery charger unit approved
by Mercedes-Benz is being used. Gases may
escape during charging and cause explosions
that may result in paint damage, corrosion or
personal injury.
A battery charger unit specially adapted for
Mercedes-Benz vehicles and tested and
approved by Mercedes-Benz is available as an
accessory. It permits the charging of the
battery in its installed position. Contact an
authorized Mercedes-Benz Center for further
information and availability.
Charge the battery in accordance with the
separate instructions for the battery charger.
GWARNING
There is a risk of acid burns during the
charging process due to the gases which
escape from the battery. Do not lean over the
battery during the charging process.GWARNING
Battery acid is caustic. Avoid contact with the
skin, eyes or clothing.
! Only charge the installed battery with a
battery charger which has been tested and
approved by Mercedes-Benz. These battery
chargers allow the battery to be charged
while still installed.
! Only use battery chargers with a
maximum charging voltage of 14.8 V.
! Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment ( Y page 481).
XOpen the hood ( Y page 456).XConnect the battery charger to the positive
terminal and earth point in the same order
as when connecting the donor battery in
the jump-starting procedure
( Y page 481).XRead the battery charger's operating
instructions before charging the battery.480BatteryBreakdown assistance

XMake sure that the two vehicles do not touch.XSecure the vehicle by applying the electric parking brake.XShift the transmission to position P.XSwitch off all electrical consumers (e.g. radio, blower, etc.).XOpen the hood ( Y page 456).
Position number A identifies the charged battery of the other vehicle or an equivalent jump-
starting device.
XRemove the cover from positive terminal :.XConnect positive terminal : on your vehicle to positive terminal ; of donor battery A
using the jumper cable, beginning with your own battery.XStart the engine of the donor vehicle and run it at idling speed.XConnect negative terminal = of donor battery A to earth point ? of your vehicle using
the jumper cable, connecting the jumper cable to donor battery A first.XStart the engine.XAllow the engine to run for a few minutes before disconnecting the jumper cable.XFirst, remove the jumper cable from earth point ? and negative terminal =, then from
positive terminal : and positive terminal ;, each time disconnecting from the battery on
your own vehicle first.XHave the battery checked at a qualified specialist workshop, e.g. an authorized Mercedes-
Benz Center. The jump-starting procedure is not a standard operating state; therefore, have
the battery checked.482Jump-startingBreakdown assistance

Fuse box in the engine compartment
Fuse box on the left in the direction of
travelXOpen the hood ( Y page 456).XRemove any existing moisture from the
fuse box using a dry cloth.XAMG vehicles: remove the control unit
above the fuse box.X To open: undo screws : with an Allen
key.XRemove bracket =.XRemove cover ;.XTo close: check whether the rubber seal is
lying correctly in cover ;.XPut cover ; back in position.XReplace bracket =.XTighten screws : using an Allen key.
!
The cover must be seated properly,
otherwise moisture or dirt could impair the
function of the fuses.
XClose the hood ( Y page 457).
Fuse box on the right in the direction of
travel
XOpen the hood ( Y page 456).XRemove any existing moisture from the
fuse box using a dry cloth.XTo open: open clamps ;.XRemove cover ; upwards.XTo close: check whether the rubber seal is
lying correctly in cover ;.XPut cover ; back in position.XFold down cover : and close clamps ;.
!
The cover must be seated properly,
otherwise moisture or dirt could impair the
function of the fuses.
XClose the hood ( Y page 457).
Engine emergency off
If the engine cannot be switched off as
described, observe the following procedure:
XTake the fuse allocation chart out of the
vehicle document wallet.XSearch for “Emergency engine shutdown”
in the fuse allocation chart.XRemove the fuses listed under "Emergency
engine shutdown".Fuses487Breakdown assistanceZ