warning lights MERCEDES-BENZ CLS 2012 Service Manual

Display messagesPossible causes/consequences and M Solutions#
Check Brake Pad
WearThe brake pads/linings have reached their wear limit.XVisit a qualified specialist workshop.$ (USA
only) J (Canada
only)
Release Parking
BrakeYou are driving with the parking brake applied. A warning tone also
sounds.XRelease the parking brake$ (USA
only) J (Canada
only)
Check Brake Fluid
LevelGRisk of accident
There is not enough brake fluid in the brake fluid reservoir.
Additionally, the red $ (USA only)/ J (Canada only)
warning lamp lights up in the instrument cluster and a warning
tone sounds.
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.XDo not add brake fluid. This will not correct the malfunction.GWARNING
Driving with the message Check Brake Fluid Level displayed can result in an accident. Have
your brake system checked immediately.
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.
Display messages219On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsPRE-SAFE
Functions Limited
See Operator's
ManualGRisk of accident
PRE-SAFE ®
Brake is defective. BAS PLUS or the distance warning
signal may also have failed.
XVisit a qualified specialist workshop.6
SRS Malfunction
Service RequiredGRisk of injury
There is a malfunction in the SRS (Supplemental Restraint
System). The 6 warning lamp also lights up in the instrument
cluster.
XVisit a qualified specialist workshop.6
Front Left
Malfunction
Service Required or
Front Right
Malfunction
Service RequiredGRisk of injury
SRS has malfunctioned at the front on the left or right. The 6
warning lamp also lights up in the instrument cluster.
XVisit a qualified specialist workshop.6
Rear Left
Malfunction
Service Required or
Rear Right
Malfunction
Service RequiredGRisk of injury
SRS has malfunctioned at the rear on the left or right. The 6
warning lamp also lights up in the instrument cluster.
XVisit a qualified specialist workshop.6
Left Side Curtain
Airbag Malfunction
Service Required or
Right Side Curtain
Airbag Malfunction
Service RequiredGRisk of injury
There is a malfunction in the left-hand and/or right-hand window
curtain air bag. The 6 warning lamp also lights up in the
instrument cluster.
XVisit a qualified specialist workshop.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.
Display messages221On-board computer and displaysZ

GWARNING
If the 45 indicator lamp remains lit with an adult occupant on the front-passenger seat
even after performing the above corrective steps, do not have any passenger use the front-
passenger seat until the system has been repaired.
Lights
i Display messages about LEDs:
This display message will only appear if all LEDs have failed.
Display messagesPossible causes/consequences and M Solutionsb
Check Left
Cornering Light
or Check Right
Cornering LightThe left or right-hand cornering light is defective.XVisit a qualified specialist workshop.b
Check Left Low
Beam or Check Right
Low BeamThe left or right-hand low-beam headlamp is defective.XVisit a qualified specialist workshop.b
Check Rear Left
Turn Signal
or Check Rear Right
Turn SignalThe rear left-hand or rear right-hand turn signal is defective.XVisit a qualified specialist workshop.b
Check Front Left
Turn Signal
or Check Front
Right Turn SignalThe front left-hand or front right-hand turn signal is defective.XVisit a qualified specialist workshop.b
Check Left Mirror
Turn Signal
or Check Right
Mirror Turn SignalThe turn signal in the left-hand or right-hand exterior mirror is
defective.XVisit a qualified specialist workshop.b
Check Center Brake
LampThe high-mounted brake lamp is faulty.XVisit a qualified specialist workshop.224Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutionsb
Active Headlamps
InoperativeThe active light function is defective.XVisit a qualified specialist workshop.b
Malfunction See
Operator's ManualThe exterior lighting is defective.XVisit a qualified specialist workshop.b
AUTO Lamp Function
InoperativeThe light sensor is defective.XVisit a qualified specialist workshop.b
Switch Off LightsThe lights are still switched on when you leave the vehicle. A
warning tone also sounds.XTurn the light switch to Ã.Adaptive Highbeam
Assist InoperativeAdaptive Highbeam Assist is defective.XVisit a qualified specialist workshop.Adaptive Highbeam
Assist Currently
Unavailable See
Operator's ManualAdaptive Highbeam Assist is deactivated and temporarily
inoperative, if:
R the windshield is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.XClean the windshield.
Adaptive Highbeam Assist is available again, if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system recognizes that the camera is fully operational again.
The Adaptive Highbeam Assist Now Available message is
displayed.
Engine
Display messagesPossible causes/consequences and M Solutions+
Check Coolant
Level See
Operator's ManualThe coolant level is too low.XAdd coolant, observing the warning notes when doing so
( Y page 282).XIf the coolant needs to be refilled more often than usual, have
the engine coolant system checked at a qualified specialist
workshop.226Display messagesOn-board computer and displays

Warning and indicator lamps in the instrument cluster
Seat belts
ProblemPossible causes/consequences and M Solutions7
After starting the
engine, the red seat
belt warning lamp lights
up for six seconds.The seat belt warning lamp reminds the driver and front passenger
to fasten their seat belts.XFasten your seat belt ( Y page 50).7
After starting the
engine, the red seat
belt warning lamp lights
up. In addition, a
warning tone sounds
for up to six seconds.GRisk of injury
The driver's seat belt is not fastened.
XFasten your seat belt ( Y page 50).
The warning tone ceases.7
The red seat belt
warning lamp lights up
after the engine starts,
as soon as the driver's
or the front-passenger
door is closed.GRisk of injury
The driver or front passenger has not fastened their seat belt.
XFasten your seat belt ( Y page 50).
The warning lamp goes out.GRisk of injury
There are objects on the front-passenger seat.
XRemove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out.Warning and indicator lamps in the instrument cluster241On-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

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.
Driving systems
ProblemPossible causes/consequences and M Solutions·
The red distance
warning lamp lights up
while the vehicle is in
motion. A warning tone
also sounds.GRisk of accident
The warning is issued if you approach a stationary vehicle or a
vehicle driving ahead of you at too high a speed.
XBe prepared to brake immediately.XPay careful attention to the traffic situation. You may have to
brake or take evasive action.
More information about DISTRONIC PLUS ( Y page 157) and
PRE-SAFE ®
Brake ( Y page 67).
Warning and indicator lamps in the instrument cluster251On-board computer and displaysZ

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

Cleaning the wiper bladesGWARNING
Before cleaning the windshield or wiper
blades, switch off the windshield wipers and
remove the SmartKey from the ignition lock.
On vehicles with KEYLESS-GO, press the
Start/Stop button repeatedly until all
indicator lamps in the instrument cluster have
gone out. The windshield wipers could
otherwise move and injure you.
! Do not pull the wiper blade. Otherwise,
the wiper blade could be damaged.
! Do not clean wiper blades too often and
do not rub them too hard. Otherwise, the
graphite coating could be damaged. This
could cause wiper noise.
XFold the wiper arms away from the
windshield.XCarefully clean the wiper blades with a
damp cloth.XFold the windshield wipers back again
before switching on the ignition.
! Hold the wiper arm securely when folding
back. The windshield could be damaged if
the wiper arm smacks against it suddenly.
Cleaning the exterior lighting
XClean the plastic lenses of the exterior
lights with a wet sponge and a mild cleaning
agent, e.g. Mercedes-Benz car shampoo or
cleaning cloths.
! Only use cleaning agents or cleaning
cloths which are suitable for plastic light
lenses. Unsuitable cleaning agents or
cleaning cloths could scratch or damage
the plastic light lenses.
Cleaning the sensorsXClean sensors : of the driving systems
with water, car shampoo and a soft cloth.
! When cleaning the sensors with a power
washer, maintain a distance between the
vehicle and the nozzle of the power washer
of at least 11.8 in (30 cm). Information
about the correct distance is available from
the equipment manufacturer.
Cleaning the rear view camera
XUse clear water and a soft cloth to clean
camera lens :.
!
Do not clean the camera lens and the area
around the rear view camera with a power
washer.
Care289Maintenance and careZ