check engine MERCEDES-BENZ S-CLASS SEDAN 2012 Owner's Guide

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 is over 248 ‡ (120 †), do not continue driving. The engine will
otherwise be damaged.
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.Display messages407On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutions4
Check Engine Oil
At Next RefuelingVehicles with an oil dipstick: the oil level has dropped to the
minimum level.XCheck the oil level when next refueling, at the latest
( Y page 459).XIf necessary, add engine oil ( Y page 462).XHave the engine checked at a qualified specialist workshop if
engine oil needs to be added more often than usual.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 459).XIf necessary, add engine oil ( Y page 459).XHave the engine checked at a qualified specialist workshop if
engine oil needs to be added more often than usual.
Information on approved engine oils can be obtained from any qualified specialist workshop
or on the Internet at http://www.mbusa.com (USA only).
! The oil level is too low. Avoid long journeys with too little engine oil. There is a risk of
engine damage.
The display messages and the corresponding symbol that indicate that the oil level is too
low must not be ignored.
Display messagesPossible causes/consequences and M Solutions4
Engine Oil Level
Low Stop Vehicle
Turn Engine OffVehicles without an oil dipstick: the engine oil level is too low.
There is a risk of engine damage.XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.XApply the parking brake.XAdd engine oil ( Y page 462) and check the oil level
( Y page 459).4
Engine Oil Level
Too HighVehicles without an oil dipstick: you have added too much engine
oil. There is a risk of damage to the engine or to the catalytic
converter.XHave the excess oil siphoned off at a qualified specialist
workshop. Observe the legal requirements.4
Engine Oil Level
Cannot Be MeasuredVehicles without an oil dipstick: the measuring system is
defective.XVisit a qualified specialist workshop.408Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutions8
Reserve FuelThe fuel level has dropped into the reserve range.XRefuel at the nearest gas station.CThere is only a very small amount of fuel in the fuel tank.XRefuel at the nearest gas station without fail.8
Gas Cap LooseThe fuel system pressure is too low. The fuel filler cap is not closed
correctly or the fuel system is leaking.XCheck that the fuel filler cap is correctly closed.
If the fuel filler cap is not correctly closed:
XClose the fuel filler cap.
If the fuel filler cap is correctly closed:
XVisit a qualified specialist workshop.8
Ultra Low-sulfur
Diesel Fuel OnlyVehicles with a diesel engine: the fuel level has fallen below the
reserve range.XRefuel at the nearest gas station.XOnly use commercially available vehicular ULTRA-LOW SULFUR
HIGHWAY DIESEL FUEL (ULSD, 15ppm SULFUR MAXIMUM).¸·
Replace Air FilterVehicles with a diesel engine: the engine air filter is dirty and must
be replaced.XVisit a qualified specialist workshop.!
Check Fuel FilterVehicles with a diesel engine: there is water in the fuel filter. The
water must be drained off.XVisit a qualified specialist workshop.Ø
Check Additive See
Oper. ManualThe DEF tank is empty.XHave the DEF tank filled as soon as possible at a qualified
specialist workshop ( Y page 325).Ø
Remaining Starts:
16The DEF level has fallen to a minimum.XHave the DEF tank filled immediately at a qualified specialist
workshop ( Y page 325).Display messages409On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsDISTRONIC PLUS
Currently
Unavailable See
Oper. ManualDISTRONIC is deactivated and temporarily inoperative. Possible
causes are:
R the DISTRONIC PLUS cover in the radiator grill is dirty.
R function is impaired due to heavy rain or snow.
R the sensors in the bumpers are dirty.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
A warning tone also sounds.
If the display message does not disappear:XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XApply the electric parking brake.XClean the DISTRONIC PLUS cover in the radiator grill
( Y page 470).XClean the bumpers ( Y page 470).XRestart the engine.
If the system detects that the sensors are fully operational, the
display message disappears.
DISTRONIC is operational again.
DISTRONIC PLUS
InoperativeDISTRONIC PLUS is defective. BAS PLUS (Brake Assist PLUS) and
PRE-SAFE ®
Brake may be inoperative as well.
A warning tone also sounds.XVisit a qualified specialist workshop.DISTRONIC PLUS
OverrideYou have depressed the accelerator pedal. DISTRONIC PLUS is no
longer controlling the speed of the vehicle.XTake your foot off the accelerator pedal.DISTRONIC PLUS
--- mphAn activation condition for DISTRONIC PLUS is not fulfilled.XCheck the activation conditions for DISTRONIC PLUS
( Y page 336).416Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutionsh
Check Tire PressureGRisk 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 515).XCheck the tire pressure. If necessary, correct the tire pressure
( Y page 499).h
Correct Tire
PressureThe 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 499).
Vehicle
Display messagesPossible causes/consequences and M SolutionsShift to P or N
to Start EngineYou have attempted to start the engine with the transmission in
position R or D.XShift the transmission to position P or N.Auxiliary Battery
Malfunction
(White display
message)The auxiliary battery for the automatic transmission is no longer
being charged.XVisit a qualified specialist workshop.Auxiliary Battery
Malfunction
(Red display message)The auxiliary battery for the automatic transmission is discharged.
If there is a malfunction in the vehicle's electrical system, you may
not be able to change the transmission position.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.XConsult a qualified specialist workshop.Apply Brake to
Shift from '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.XApply the electric parking brake.Display messages419On-board computer and displaysZ

Safety systemsProblemPossible 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.XApply the electric 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 rectify 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.
424Warning and indicator lamps in the instrument clusterOn-board computer and displays

ProblemPossible causes/consequences and M Solutionså
The yellow ESP ®
OFF
warning lamp is lit while
the engine is running.GRisk of accident
ESP ®
is deactivated. ESP ®
will not stabilize the vehicle if it starts
to skid or if a wheel starts to spin.
XReactivate ESP ®
.
For exceptions: ( Y page 75).XAdapt your driving style to suit the road and weather conditions.
If ESP ®
cannot be activated:
XHave ESP ®
checked at a qualified specialist workshop.֌
The yellow ESP ®
and
ESP ®
OFF warning
lamps are lit while the
engine is running.GRisk of accident
ESP ®
, BAS, BAS PLUS, PRE-SAFE ®
, PRE-SAFE ®
Brake, the HOLD
function and hill start assist are not available due to a malfunction.
ESP ®
will not stabilize the vehicle if it starts to skid or if a wheel
starts to spin.
The brake system continues to function normally, but without the
functions listed above.
ATTENTION ASSIST 21
is deactivated.
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XVisit a qualified specialist workshop.21 Not available on hybrid vehicles.Warning and indicator lamps in the instrument cluster427On-board computer and displaysZ

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.
Engine
ProblemPossible 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 (for vehicles with a gasoline engine)
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 must immediately visit a qualified
specialist workshop as soon as the yellow Check Engine warning
lamp lights up. This is due to the legal requirements in effect in
these states. If in doubt, check whether such legal regulations
apply in the state in which you are currently driving.
Vehicles with a diesel engine: the fuel tank has been run dry
( Y page 324).XStart the engine three to four times after refueling.
If the yellow Check Engine warning lamp goes out, emergency
running mode is canceled. The vehicle need not be checked.Warning and indicator lamps in the instrument cluster429On-board computer and displaysZ

ProblemPossible causes/consequences and M SolutionsThe yellow reserve fuel
warning lamp flashes
while the vehicle is in
motion.
In addition, the ;
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.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.
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
You are approaching a vehicle or a stationary obstacle in your line
of travel 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 336) and
PRE-SAFE ®
Brake ( Y page 77).
430Warning and indicator lamps in the instrument clusterOn-board computer and displays

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 panel.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 (40cm), 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 (20cm).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. The readings of
the on-board-diagnostic system may
otherwise 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: be sure to read the "HYBRID"
supplement. Otherwise, you could 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 (1,000 km). The oil
Engine compartment459Maintenance and careZ