2012 MERCEDES-BENZ S-Class check engine

Display messagesPossible causes/consequences and M Solutions¸·
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 321).Ø
Remaining Starts:
16The DEF level has fallen to a minimum.XHave the DEF tank filled immediately at a qualified specialist
workshop. ( Y page 321)
Driving systems
Display messagesPossible causes/consequences and M SolutionsÀ
Attention Assist:
Pause!Based on specific criteria, ATTENTION ASSIST 21
has determined
that the driver is tired or paying less attention. A warning tone also
sounds.XIf necessary, take a break.
During long journeys, take regular breaks in good time so you get
enough rest.
À
Attention Assist
InoperativeATTENTION ASSIST 21
has failed.XVisit a qualified specialist workshop.Á
Night View Assist
InoperativeNight View Assist Plus is defective.XVisit a qualified specialist workshop.21 Not available on hybrid vehicles.408Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsDISTRONIC PLUS
Currently
Unavailable See
Operator's ManualDISTRONIC PLUS is deactivated and is temporarily inoperative if:
R the DISTRONIC PLUS cover in the radiator grill is dirty.
R its 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.
DISTRONIC PLUS is operational again and the display message
disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R the system is within the operating temperature range.
If the display message continues to be displayed:XClean the DISTRONIC PLUS cover in the radiator grill
( Y page 467).XClean the bumpers ( Y page 467).XRestart the engine.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 332).414Display 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 513).XCheck the tire pressure. If necessary, correct the tire pressure
( Y page 497).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 497).
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 messages417On-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.XEngage 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.
422Warning 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 ®
.
Exceptions: ( Y page 71).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 22
is deactivated.
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XVisit a qualified specialist workshop.22 Not available on hybrid vehicles.Warning and indicator lamps in the instrument cluster425On-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 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.
Vehicles with a diesel engine: the fuel tank has been run dry
( Y page 320).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 cluster427On-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 ;
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.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
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 332) and
PRE-SAFE ®
Brake ( Y page 73).
428Warning 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 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