check engine MERCEDES-BENZ S-Class 2012 W221 Service Manual

consumption may be higher than this when
the vehicle is new or if you frequently drive at
high engine speeds.
Checking the oil level using the oil
dipstick
On vehicles with a 12-cylinder engine, the oil
level can be checked using the on-board
computer. On all other models, the dipstick
must be used to check the engine oil level.
Example: vehicles with a gasoline engine
Example: vehicles with 4MATIC
XPark the vehicle on a level surface.
To check the oil level with the engine at
operating temperature, switch the engine
off and wait for approximately five minutes.XPull oil dipstick : out of the dipstick guide
tube.XWipe off oil dipstick :.XSlowly slide oil dipstick : into the guide
tube to the stop, and take it out again.
If the level is between MIN mark = and
MAX mark ;, the oil level is correct.XIf the fuel level has sunk to MIN mark = or
below, add 0.55 to 1.1 US qt (0.5 to 1.0 l)
engine oil.
Checking the oil level using the on-
board computer
On vehicles with a 12-cylinder engine, the oil
level can be checked using the on-board
computer. On all other models, the dipstick
must be used to check the engine oil level.
XPark the vehicle on a level surface.
To check the oil level with the engine at
normal operating temperature, switch the
engine off and wait for approximately five
minutes.XMake sure that the SmartKey is in position
2 in the ignition lock.XPress the ; or = button to select the
Service menu.XPress the : or 9 button to select
Engine Oil Level .XPress the a button.
The multifunction display shows the
following message: Engine Oil Level
Measuring Now Measurement correct
only if vehicle level.
The measurement takes a few seconds. You
will see one of the following messages in the
multifunction display:
R Engine Oil Level OK
R Add 1.0 l Engine Oil At Next
Refueling
R Add 1.5 l Engine Oil At Next
Refueling
R Add 2.0 l Engine Oil At Next
Refueling
XAdd oil if necessary.
If the engine is at normal operating
temperature and the Engine Oil Level
458Engine compartmentMaintenance and care

Reduce Oil Level message appears, the
engine oil level is too high.XHave excess oil siphoned off.
! Do not add too much oil. Adding too much
oil can result in damage to the engine or the
catalytic converter. Have excess oil
siphoned off.
If the For Engine Oil Level Ignition
Must be On message appears:
XTurn the SmartKey to position 2 in the
ignition lock.
If the Need More Time to Check Engine
Oil Level message appears:
XIf the engine is at normal operating
temperature: repeat the measurement
after about five minutes.
If the engine is not at normal operating
temperature (e.g. if the engine was only
started briefly): repeat the measurement
after about 30 minutes.
If the Engine Oil Level Not When
Engine On message appears:
XSwitch off the engine.XIf the engine is at normal operating
temperature: wait about five minutes
before carrying out the measurement.
If the engine is not at normal operating
temperature, e.g. if the engine was only
started briefly: wait about 30 minutes
before carrying out the measurement.
i If you wish to cancel the measurement,
press the % button on the multifunction
steering wheel.
Adding engine oil
GWARNING
If engine oil comes into contact with hot
engine parts, it may ignite and you could burn
yourself. Do not spill any engine oil on hot
engine parts.
HEnvironmental note
When adding oil, take care not to spill any. If
oil enters the soil or waterways, it is harmful
to the environment.
! Use only engine oils and oil filters that
have been approved for vehicles equipped
with a service system. A list of the engine
oils and oil filters tested and approved in
accordance with the Mercedes-Benz
Specifications for Service Products can be
called up by visiting http://
www.mbusa.com (USA only). More
information about tested and approved
engine oils and oil filters is available from
any authorized Mercedes-Benz Center.
Damage to the engine or exhaust system is
caused by the following:
R using engine oils and oil filters which
have not been specifically approved for
the service system.
R replacing the engine oil or oil filter after
the replacement interval required by the
service system has elapsed
R using engine oil additives.
! Do not add too much oil. If the oil level is
above the "max" mark on the dipstick, too
much oil has been added. This can lead to
damage to the engine or the catalytic
converter. Have excess oil siphoned off.
Example: engine oil cap
Engine compartment459Maintenance 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

XIf necessary, add coolant that has been
tested and approved by Mercedes-Benz.XReplace cap : and turn it clockwise as far
as it will go.
For further information on coolant, see
( Y page 529).
Windshield washer system and
headlamp cleaning system
The washer fluid reservoir is used for both the
windshield washer system and the headlamp
cleaning system.
i Vehicle components and their service
products must match. You should,
therefore, only use products that have been
tested and approved by Mercedes-Benz.
Information on tested and approved
products can be obtained at any authorized
Mercedes-Benz Center or on the Internet at
http://www.mbusa.com (USA only).
GWARNING
Washer solvent/antifreeze is highly
flammable. Do not spill washer solvent/
antifreeze on hot engine parts, because it may
ignite and burn. You could be seriously
burned.
! At temperatures below freezing: always
fill the washer fluid reservoir with a mix of
water and windshield washer concentrate
(e.g. MB WinterFit). There is otherwise a
risk of damaging the windshield washer
system/headlamp cleaning system.
! Only use washer fluid concentrate which
is suitable for plastic lenses. Unsuitable
washer fluid concentrate could damage the
plastic lenses of the headlamps.
! Do not add distilled or de-ionized water to
the washer fluid container. Otherwise, the
level sensor may be damaged.
i Add windshield washer concentrate, e.g.
MB SummerFit, to the washer fluid all year
round.
Example: washer fluid reservoir
XMix the windshield washer fluid in a
container beforehand.XAt temperatures above freezing: fill the
washer fluid reservoir with a mix of water
and windshield washer concentrate (e.g.
MB SummerFit).XAt temperatures below freezing: fill the
washer fluid reservoir with a mix of water
and windshield washer concentrate (e.g.
MB WinterFit). Adapt the mixing ratio to the
outside temperature. For information on
the mixing ratio ( Y page 529).XTo open: pull cap : upwards by the tab.XAdd the premixed washer fluid.XTo close: press cap : onto the filler neck
until it engages.
Brake fluid level
! If you notice that the brake fluid level in
the brake fluid reservoir has fallen to the
MIN mark or less, check the brake system
immediately for leaks. Also check the
thickness of the brake linings. Contact a
qualified specialist workshop, e.g. an
authorized Mercedes-Benz Center
immediately.
Do not add brake fluid. This does not
correct the error.
Only check the brake fluid level when the
vehicle is stationary and on a level surface.
Engine compartment461Maintenance and careZ

Risk of explosionFire, naked flames and
smoking are prohibited
when handling the battery.
Avoid creating sparks.Battery acid is caustic.
Avoid contact with the skin,
eyes or clothing.
Wear suitable protective
clothing, in particular
gloves, an apron and a face
mask.
Immediately rinse acid
splashes off with clean
water. Consult a doctor if
necessary.Wear eye protection.Keep children away.Observe this Operator's
Manual.HEnvironmental noteBatteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separately
and recycled to protect the
environment.Dispose of batteries in an
environmentally friendly
manner. Return discharged
batteries to a qualified
specialist workshop, e.g. an
authorized Mercedes-Benz
Center, or to a specialcollection point for old
batteries.GWARNING
Failure to follow these instructions can result
in severe injury or death.
Never lean over batteries while connecting.
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.
GWARNING
Do not place any metal objects on the battery
as this could result in a short circuit.
Use leak-proof batteries only to avoid the risk
of acid burns in the event of an accident.
Take care that you do not become statically
charged, e.g. by wearing synthetic clothing or
rubbing against textiles. For this reason, you
also should not pull or push the battery over
carpets or other synthetic materials.
Never touch the battery first. First, touch the
outside body of the vehicle in order to release
any possible electrostatic charges.
Do not rub the battery with rags or cloths. The
battery could explode if touched due to
electrostatic charge or due to spark
formation.
! Before working on the battery, e.g.
loosening the battery terminals, switch off
the engine and remove the SmartKey from
the ignition. On vehicles with KEYLESS-GO,
make sure that the ignition is switched off.
Check that all the indicator lamps in the
instrument cluster are off. You may
otherwise destroy electronic components,
such as the alternator.
Battery479Breakdown assistanceZ

! 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

RIPA
R TBA
For MTBE, the concentration should not
exceed 15%.
The concentration of methanol in gasoline
including other additives must not exceed 3%.
Using mixtures of methanol and ethanol is not
permitted. Gasohol, a mixture of 10% ethanol
and 90% unleaded gasoline, can be used.
All of these mix fuels must fulfill the fuel
requirements, e.g.:
R knock resistance
R boiling point
R vapor pressure
Diesel engines – important safety notes
! Only use commercially available ULTRA-
LOW SULFUR DIESEL FUEL (ULSD, 15 ppm
MAXIMUM SULFUR) that meets the
ASTM D975 standard. Failure to use
ULTRA-LOW SULFUR DIESEL FUEL (ULSD)
can severely damage the vehicle's exhaust
gas aftertreatment system.
! Do not fill the tank with gasoline. Do not
blend diesel fuel with gasoline or kerosene.
Otherwise, the fuel system and the engine
could be damaged.
To prevent malfunctions, diesel fuel with
improved flow characteristics is available in
the winter months. Check with your gas
station.
Information on the fuel grade can usually be
found on the gas pump. If the information
cannot be found on the gas pump, ask the gas
station personnel. For further information,
consult an authorized Mercedes-Benz Center
or go to the Internet site
http://www.mbusa.com (USA only).
Diesel engines – fuels containing
biodiesel (FAME [fatty acid methyl ester])
Mercedes-Benz USA approves the use of B5
(ULSD with a maximum of up to five percent
by volume biodiesel) for all diesel engineswith common rail direct injection (CDI) and
BlueTEC.
Pure biodiesel and diesel fuels that have a
higher percentage of biodiesel, e.g. B20, can
damage the fuel system and the engine and
are therefore not approved.
For further information, please ask the gas
station personnel. The label on the gas pump
must indicate clearly that the B5 biodiesel
blend fulfills the ULSD standard. If the label
is not clear, do not refuel the vehicle.
Do not refuel your vehicle with fuels unless
they have been approved by Mercedes-Benz.
Additives in gasoline
One of the main problems of poor fuel quality
is the forming of deposits that are caused
during the gasoline combustion process.
Mercedes-Benz recommends that you use
fuel brands that have the additives.
If you use fuels without these additives for an
extended period of time, there may be a
buildup of carbon deposits, especially on the
inlet valves and in the combustion chamber.
This could lead to engine problems, e.g.:
R longer engine warm-up phase
R uneven idle
R engine noise
R misfiring
R loss of power
Carbon deposits may form if the availability
of gasoline with relevant additives is
insufficient (in certain regions). In this case,
Mercedes-Benz recommends the use of
additives that have been approved for
Mercedes-Benz vehicles.
Consult an authorized Mercedes-Benz Center
or go to the Internet site
http://www.mbusa.com (USA only) for a list
of approved products. Observe the
instructions for use on the product label.
Do not mix other fuel additives with fuel. This
causes unnecessary costs and could damage
the engine.
526Service products and capacitiesTechnical data

fluids can be obtained from any authorized
Mercedes-Benz Center or on the Internet at
http://bevo.mercedes-benz.com.
Coolant
Important safety notes
The coolant is a mixture of water and
antifreeze/corrosion inhibitor. It performs
the following tasks:
R corrosion protection
R antifreeze protection
R raising the boiling point
The engine cooling system is filled at the
factory with coolant that contains an
antifreeze/corrosion inhibitor that ensures
protection down to approximately -35 ‡
(-37 †).
! Only add coolant that has been premixed
with the desired antifreeze protection.
Otherwise, the engine could be damaged.
Further information on coolants and on
filling can be found in the Mercedes-Benz
Specifications for Service Products, MB
Approval 310.1, e.g. on the Internet at
http://bevo.mercedes-benz.com . You can
also consult an authorized Mercedes-Benz
Center.
! Always use a suitable coolant mixture,
even in countries where high temperatures
prevail.
Otherwise, the engine cooling system is not
sufficiently protected from corrosion and
overheating.
If the coolant has antifreeze protection down
to -35 ‡ (-37 †), the boiling point of the
coolant under operating conditions is
approximately 266 ‡ (130 †).
Your vehicle has a range of aluminum
components. Aluminum components in the
engine make it necessary to use antifreeze/
corrosion inhibitor coolant that has been
specifically formulated to protect the
aluminum parts. Using other antifreeze/
corrosion inhibitors without these
characteristics affects the service life.
The coolant must be used throughout the year
in order to maintain the necessary corrosion
protection and to provide protection from
overheating. In the Service Booklet, you can
find information on the intervals for renewal.
The renewal interval is determined by the
coolant type and the engine cooling system
design. The renewal interval in the Service
Booklet is only valid if the coolant is renewed
or filled up with Mercedes-Benz approved
products. Therefore, only use MB 325.0 or
326.0 anticorrosion/antifreeze or another
Mercedes-Benz approved product of the
same specification.
Information on other products with the same
specifications that are approved by
Mercedes-Benz can be obtained at an
authorized Mercedes-Benz Center or on the
Internet at http://bevo.mercedes-benz.com.
The coolant is checked at every maintenance
interval at an authorized Mercedes-Benz
Center.
The antifreeze/corrosion inhibitor
concentration in the engine cooling system
should:
R be at least 50%. This will protect the engine
cooling system against freezing down to
approximately -35 ‡ (-37 † ).
R not exceed 55% (antifreeze protection to
-49 ‡ [-45 † ]); otherwise, heat will not
dissipate as effectively.
If the coolant level is too low, MB 325.0 or
326.0 anticorrosion/antifreeze should be
added. Have the engine cooling system
checked for possible leaks.
Windshield/headlamp cleaning
system
GWARNING
Washer solvent/antifreeze is highly
flammable. Do not spill washer solvent/
antifreeze on hot engine parts, because it may
Service products and capacities529Technical dataZ