check engine light MERCEDES-BENZ S-Class 2012 W221 User Guide

XPress a.
The current selection is displayed.XTo activate/deactivate: press a
again.
When ATTENTION ASSIST ( Y page 356) is
activated, the À symbol appears in the
multifunction display when the ignition is on.
Activating/deactivating Blind Spot
Assist
You can use the Blind Spot Assist
function to activate or deactivate Blind Spot
Assist ( Y page 360) or Active Blind Spot
Assist ( Y page 364).
XPress = or ; on the steering wheel
to select the DriveAssist menu.XPress 9 or : to select Blind Spot
Assist .XPress a.
The current selection is displayed.XTo activate/deactivate: press a
again.
Activating/deactivating Lane Keeping
Assist
You can use the Lane Keeping Assist
function to activate/deactivate Lane Keeping
Assist ( Y page 362) or Active Lane Keeping
Assist ( Y page 367).
XPress the = or ; button on the
steering wheel to select the DriveAssist
menu.XPress the 9 or : button to select
Lane Keeping Assist .XPress a.
The current selection is displayed.XTo activate/deactivate: press a
again.
If Lane Keeping Assist or Active Lane keeping
Assist is activated, the multifunction display
shows the à symbol when the ignition is
switched on.
Service menu
In the Service menu you can:
R call up display messages ( Y page 388)
R check the tire pressure electronically
( Y page 497)
R call up the service due date ( Y page 462)
R check the oil level ( Y page 457)
Settings menu
Introduction
The Settings menu can be used for:
R switching the daytime running lamps on/
off
R switching Adaptive Highbeam Assist on/
off
R showing or hiding the additional
speedometer
R selecting the units for speed and distance
R switching the belt adjustment on/off
R activating/deactivating the radar sensor
system
Switching the daytime running lamps
on/off
This function is not available in Canada.
If you have activated the Daytime Running
Light function and the light switch is in the
$ or c position, the daytime running
lamps are switched on automatically when
the engine is running.
In the dark, the following also light up:
R the parking lamps
R the tail lamps
R the license plate lamp
R the side marker lamps
If you turn the light switch to a different
position, the corresponding lights are
switched on. If you switch off the daytime
running lamps at night, make sure that the
light switch is set to L or c .
The factory setting is On.
Menus and submenus385On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutions$ (USA
only) J (Canada
only)
Service See Oper.
ManualThere is a malfunction in the system. The brake system continues
to operate normally.XDrive on carefully.XVisit a qualified specialist workshop.$ (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 electric parking brake.XConsult a qualified specialist workshop.XDo not add brake fluid. This will not rectify 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 messagesPossible causes/consequences and M SolutionsG
Tele Aid
InoperativeUSA only: one or more of the main functions in the mbrace system
are malfunctioning.
Canada only: one or more of the main functions of the TELEAID
system are malfunctioning.XUSA only: have the mbrace system checked at a qualified
specialist workshop.XCanada only: have the TELEAID system checked at a qualified
specialist workshop.PRE-SAFE
Inoperative See
Oper. ManualGRisk of injury
Important functions of PRE-SAFE ®
have failed. All other occupant
safety systems, e.g. air bags, remain available.
XVisit a qualified specialist workshop immediately.396Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutionsb
Please Switch Off
LightsThe lights are still switched on when you leave the vehicle. A
warning tone also sounds.XTurn the light switch to $ or c .
or
XIf the rear fog lamp is switched on: press the light switch in to
the stop.Adaptive High-beam
Assist inoperativeAdaptive Highbeam Assist is defective.XVisit a qualified specialist workshop.
Engine
Display messagesPossible causes/consequences and M Solutions+
Check Coolant
Level See Oper.
ManualThe coolant level is too low.XAdd coolant, observing the warning notes when doing so
( Y page 460).XIf coolant needs to be added more often than usual, have the
engine coolant system checked at a qualified specialist
workshop.GWARNING
Do not spill antifreeze on hot engine parts. Antifreeze contains ethylene glycol which may burn
if it comes into contact with hot engine parts. You could be seriously burned.
! The coolant level is too low. Avoid making long journeys with too little coolant in the cooling
system. The engine will otherwise be damaged.
The display messages and the corresponding symbol that indicate that the coolant level is
too low must not be ignored.
404Display messagesOn-board computer and displays

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