Workshop MERCEDES-BENZ CLS-Class 2012 W218 Repair Manual

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.6
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 cluster247On-board computer and displaysZ

EngineProblemPossible causes/consequences and M Solutions;
The yellow Check
Engine warning lamp
lights up while the
engine is running.There may be a malfunction, for example:
R in the engine management
R in the fuel injection system
R in the exhaust system
R in the ignition system
R in the fuel system
The emission limit values may be exceeded and the engine may
be running in emergency mode.XHave the vehicle checked as soon as possible at a qualified
specialist workshop.
i In some states, you are required by law to immediately visit a
qualified specialist workshop as soon as the yellow Check
Engine warning lamp lights up. If in doubt, check whether such
legal regulations apply in the state/province in which you are
currently driving.
8
The yellow reserve fuel
warning lamp flashes
while the vehicle is in
motion. In addition, the
yellow Check Engine
warning lamp ;
may light up.The fuel system pressure is too low. The fuel filler cap is not closed
correctly or the fuel system is leaking.XObserve the additional display messages in the multifunction
display.XCheck that the fuel filler cap is correctly closed.XIf the fuel filler cap is not correctly closed: close the fuel filler
cap.XIf the fuel filler cap is closed: visit a qualified specialist
workshop.8
The yellow reserve fuel
warning lamp lights up
while the engine is
running.The fuel level has dropped into the reserve range.XRefuel at the nearest gas station.248Warning and indicator lamps in the instrument clusterOn-board computer and displays

ProblemPossible causes/consequences and M Solutions?
The red coolant
warning lamp lights up
while the engine is
running and the coolant
temperature gauge is
at the start of the scale.The temperature sensor for the coolant temperature gauge is
defective.
The coolant temperature is no longer being monitored. There is a
risk of engine damage if the coolant temperature is too high.XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions. Do not continue
driving under any circumstances.XEngage the parking brake.XConsult a qualified specialist workshop.Warning and indicator lamps in the instrument cluster249On-board computer and displaysZ

ProblemPossible causes/consequences and M Solutions?
The red coolant
warning lamp comes on
while the engine is
running.The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator
may be blocked or the electric engine radiator fan may be
malfunctioning.
The coolant is too hot and the engine is no longer being cooled
sufficiently.XObserve the additional display messages in the multifunction
display.XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.XAllow the engine and coolant to cool.XCheck the coolant level and add coolant (Y page 282). Observe
the warning notes.XIf you need to add coolant more often than usual, have the
engine coolant system checked.XMake sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.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 red coolant
warning lamp comes on
while the engine is
running. A warning tone
also sounds.The coolant temperature has exceeded 248 ‡ (120 †). The
airflow to the engine radiator may be blocked or the coolant level
may be too low.
The engine is not being cooled sufficiently and may be damaged.XObserve the additional display messages in the multifunction
display.XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.XAllow the engine and coolant to cool.XCheck the coolant level and add coolant (Y page 282). Observe
the warning notes.XIf you need to add coolant more often than usual, have the
engine coolant system checked.XMake sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.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.250Warning and indicator lamps in the instrument clusterOn-board computer and displays

TiresProblemPossible causes/consequences and M Solutionsh
USA only:
The yellow tire pressure
monitor warning lamp
(pressure loss/
malfunction) is lit.
Canada only:
The yellow tire pressure
monitor warning lamp
(pressure loss) is lit.GRisk of accident
The tire pressure monitor has detected a loss of pressure in at
least one of the tires.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XObserve the additional display messages in the multifunction
display.XCheck the tire pressure. If necessary, correct the tire pressure
( Y page 322).XIf necessary, change a wheel ( Y page 338).h
USA only:
The yellow tire pressure
monitor warning lamp
(pressure loss/
malfunction) flashes for
60 seconds and then
remains lit.The tire pressure monitor is faulty.XObserve the additional display messages in the multifunction
display.XVisit a qualified specialist workshop.GWARNING
Each tire, including the spare (if provided), should be checked at least every two weeks when
cold and inflated to the pressure recommended by the vehicle manufacturer on the Tire and
Loading Information placard on the driver's door B-pillar or, if available, the tire pressure label
on the inside of the fuel filler flap. If your vehicle has tires of a different size than the size indicated
on the Tire and Loading Information placard or the tire pressure label, you should determine the
proper tire pressure for those tires.
As an added safety feature, your vehicle has been equipped with a tire pressure monitoring
system (TPMS) that illuminates a low tire pressure telltale when one or more of your tires are
significantly underinflated. Accordingly, when the low tire pressure telltale illuminates, you should
stop and check your tires as soon as possible, and inflate them to the proper pressure. Driving
on a significantly underinflated tire causes the tire to overheat and can lead to tire failure.
Underinflation also reduces fuel efficiency and tire tread life, and may affect the vehicle's handling
and stopping ability. Please note that the TPMS is not a substitute for proper tire maintenance,
and it is the driver's responsibility to maintain correct tire pressure, even if underinflation has
not reached the level to trigger illumination of the TPMS low tire pressure telltale.
USA only:
Your vehicle has also been equipped with a TPMS malfunction indicator to indicate when the
system is not operating properly. The TPMS malfunction indicator is combined with the low tire
pressure telltale. When the system detects a malfunction, the telltale will flash for approximately
1 minute and then remain continuously illuminated. This sequence will continue upon subsequent
252Warning and indicator lamps in the instrument clusterOn-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 22).
Loading guidelines
GWARNING
Always fasten items being carried as securely
as possible. Use cargo tie-down rings and
fastening materials appropriate for the weight
and size of the load.
In an accident, during hard braking or sudden
maneuvers, loose items will be thrown around
inside the vehicle. This can cause injury to
vehicle occupants unless the items are
securely fastened in the vehicle.
To help avoid personal injury during a collision
or sudden maneuver, exercise care when
transporting cargo. Do not pile luggage or
cargo higher than the seat backrests.
The trunk is the preferred place to carry
objects.
Never drive a vehicle with the trunk open.
Deadly carbon monoxide (CO) gases may
enter vehicle interior resulting in
unconsciousness and death.
The handling characteristics of a laden
vehicle are dependent on the distribution of
the load within the vehicle. For this reason,
you should observe the following notes when
transporting a load:
R when transporting a load, never exceed the
maximum permissible gross vehicle weight
or the gross axle weight rating of the
vehicle (including occupants). The values
are specified on the vehicle identification
plate on the B-pillar of the driver's door.
R position heavy loads as far forwards as
possible and as low down in the trunk as
possible.
R the load must not protrude above the upper
edge of the seat backrests.
R always place the load against the rear or
front seat backrests. Make sure that the
seat backrests are securely locked into
place.
R always place the load behind unoccupied
seats if possible.
R secure the load with sufficiently strong and
wear-resistant tie down. pad sharp edges
for protection.
Stowage areas
Stowage compartments
Important safety notes
GWARNING
To help avoid personal injury during a collision
or sudden maneuver, exercise care when
storing objects in the vehicle. Put luggage or
cargo in the trunk if possible.
Do not pile luggage or cargo higher than the
seat backrests.
Keep compartment lids closed. This will help
to prevent stored objects from being thrown
about and injuring vehicle occupants during
R braking
R vehicle maneuvers
R an accident
Stowage compartments in the front
Glove box
i The glove box can be ventilated
( Y page 128).
256Stowage areasStowing and features

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 22).
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
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
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
XMake sure that the windshield wipers are
switched off.GWARNING
The windshield wipers and wiper linkage
could be set in motion.
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.
280Engine compartmentMaintenance and care

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 351).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.
The brake fluid level is correct if it is between
MIN marking ; and MAX marking : on the
brake fluid reservoir.
Maintenance
Service interval display
Service messages
Information on the type of service and service
intervals (see separate Service Booklet).
You can obtain further information from an
authorized Mercedes-Benz Center or at
http://www.mbusa.com (USA only).
The service interval display informs you of the
next service due date.
If a service due date has been exceeded, you
also hear an acoustic signal.
The multifunction display shows a service
message for a few seconds, e.g.
Next service A due in .. days
Service A due
Service A overdue by ... days
The letter indicates which service is due. A
stands for a minor service and B for a major
service. A number or another letter may be
displayed after the letter. This figure indicates
any necessary additional maintenance work
to be performed.
You can obtain further information from an
authorized Mercedes-Benz Center.
The service interval display does not take into
account any periods of time during which the
battery is disconnected.
284MaintenanceMaintenance and care

Maintaining the time-dependent service
schedule:XNote down the service due date displayed
in the multifunction display before
disconnecting the battery.
or
XSubtract the battery disconnection periods
from the service date shown on the display
after reconnecting the battery.
Hiding a service message
XPress the % or a button on the
steering wheel.
Displaying a service message
XSwitch on the ignition.XPress = or ; on the steering wheel
to select the Serv. menu.XPress 9 or : to select the ASSYST
PLUS submenu and press a to confirm.
The service due date appears in the
multifunction display.
Please bear the following in mind
Resetting service interval display
If the qualified specialist workshop, e.g. a
Mercedes-Benz Center, carried out the
maintenance work, the service interval
display will be reset.
Further information, on maintenance for
example, can be obtained at an authorized
Mercedes-Benz Center or directly from
Mercedes-Benz.
! If the service interval display has been
reset unintentionally, have the setting
corrected at a Mercedes-Benz Center.
Have service work carried out as described
in the Service Booklet. This may otherwise
lead to increased wear and damage to the
major assemblies or the vehicle.
Driving abroad
An extensive Mercedes-Benz Service network
is also available in other countries. You can
obtain further information from any
authorized Mercedes-Benz Center.
Care
Notes on care
Regular care of your vehicle is a condition for
retaining the quality in the long term.
Use care products and cleaning agents
recommended and approved by Mercedes-
Benz.
GWARNING
Many cleaning products can be hazardous.
Some are poisonous, others are flammable.
Always follow the instructions on the
particular container. Always open your
vehicle's doors or windows when cleaning the
inside.
Never use fluids or solvents that are not
designed for cleaning your vehicle.
Always lock away cleaning products and keep
them out of reach of children.
! For cleaning your vehicle, do not use any
of the following:
R dry, rough or hard cloths
R abrasive cleaning agents
R solvents
R cleaning agents containing solvents
Do not scrub.
Do not touch the surfaces or protective
films with hard objects, e.g. a ring or ice
scraper. You could otherwise scratch or
damage the surfaces and protective film.
HEnvironmental note
Dispose of empty packaging and cleaning
cloths in an environmentally responsible
manner.
Care285Maintenance and careZ

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
Rtrim 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
cleaning. Braking heats the brake discs and
the brake pads/linings, thus drying them.
The vehicle can then be parked.
Cleaning the paintwork
Scratches, corrosive deposits, areas affected
by corrosion and damage caused by
inadequate care cannot always be completely
repaired. In such cases, visit a qualified
specialist workshop, e.g. an authorized
Mercedes-Benz Center.
XRemove impurities immediately, where
possible, whilst avoiding rubbing too hard.XSoak insect remains with insect remover
and rinse off the treated areas afterwards.XSoak bird droppings with water and rinse
off the treated areas afterwards.XRemove coolant, brake fluid, tree resin,
oils, fuels and greases by rubbing gently
with a cloth soaked in petroleum ether or
lighter fluid.XUse tar remover to remove tar stains.XUse silicone remover to remove wax.
! Do not affix:
R stickers
R films
R magnetic plates or similar items
Care287Maintenance and careZ