check engine MERCEDES-BENZ R-Class 2011 W251 Owner's Guide

Display messagesPossible causes/consequences and M Solutions?The engine fan is faulty.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-start driving.#The battery is not being charged.
Possible causes are:
R a faulty 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 OK:
XVisit a qualified specialist workshop.#
Battery/
Alternator Stop
VehicleThe battery is faulty.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.4
Check engine oil
level at next
refuelingThe oil level is too low.XCheck the oil level ( Y page 279).XIf necessary, add the engine oil ( Y page 280).XHave the engine checked for leaks if engine oil has 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.
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Display messagesPossible causes/consequences and M SolutionsCThere is only a small amount of fuel in the fuel tank.XRefuel at the nearest gas station.8
Reserve FuelThe fuel level has fallen below the reserve range.
The fuel tank must be filled up to at least the reserve fuel level;
otherwise, engine running may be impaired.XRefuel at the nearest gas station.8
Gas Cap OpenThe 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.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
Ultra Low-sulfur
Diesel Fuel OnlyVehicles with a diesel engine: the fuel level has fallen below the
reserve range.XCheck that the fuel filler cap is correctly closed.XRefuel at the nearest gas station.XOnly use commercially available vehicular ULTRA-LOW SULFUR
DIESEL FUEL (ULSD, 15 ppm SULFUR MAXIMUM).¸
Replace air filterVehicles with a diesel engine: the engine air filter is contaminated
and must be replaced. XVisit a qualified specialist workshop.·
Clean 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
Operator's ManualThe AdBlue ®
tank is empty.XHave the AdBlue ®
tank filled as soon as possible at a qualified
specialist workshop ( Y page 165).
Visit a qualified specialist workshop.Ø
Remaining Starts:
20The AdBlue ®
level has fallen to a minimum.XHave the AdBlue ®
tank filled as soon as possible at a qualified
specialist workshop ( Y page 165).
Visit a qualified specialist workshop.Display messages227On-board computer and displaysBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 227Z

Display messagesPossible causes/consequences and M SolutionsBlind Spot Assist
Currently
Unavailable See
Operator's ManualBlind Spot Assist is temporarily inoperative if:
R the sensors are dirty.
R its function is impaired due to heavy rain or snow.
R the radar sensor system is outside the operating temperature
range.
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 on-board voltage is too low.
The yellow 9 indicator lamps also light up in the exterior
mirrors.
Blind Spot Assist is operational again and the display message
disappears when:
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 radar sensor system is back within the operating
temperature range.
If the display message continues to be displayed:XClean the sensors ( Y page 287).XRestart the engine.Blind Spot Assist
InoperativeBlind Spot Assist is faulty.
The yellow 9 indicator lamps also light up in the exterior
mirrors.XVisit a qualified specialist workshop.Cruise Control
InoperativeCruise control is faulty. XVisit a qualified specialist workshop.Cruise Control
--- mph A condition for activating cruise control has not been met.
You wanted to save a speed of less than 20 mph (30 km/h).XIf the situation allows, drive faster than 20 mph (30 km/h) and
save the speed.XCheck the activation conditions for cruise control
( Y page 173).DISTRONIC
--- MPH An activation condition for DISTRONIC is not fulfilled.XIf the situation allows, drive faster than 20 mph (30 km/h) and
save the speed.XCheck activation conditions for DISTRONIC ( Y page 175).Display messages229On-board computer and displaysBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 229Z

Display messagesPossible causes/consequences and M Solutionsh
Tire Pressure
Check TiresGRisk 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 the wheel ( Y page 336).XCheck the tire pressure. If necessary, correct the tire pressure
( Y page 327).h
Please correct the
tire pressuresThe tire pressure is insufficient 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 327).
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
MalfunctionThe auxiliary battery for the automatic transmission is no longer
being charged.XVisit a qualified specialist workshop.Depress brake
to shift out of PYou 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.XEngage the parking brake.Drive to workshop
without shifting
gearsYou cannot change the transmission position due to a malfunction.
If transmission position D is selected:XDrive to a qualified specialist workshop without shifting the
transmission from position D.
If transmission position R, N or P is selected:
XNotify a qualified specialist workshop or breakdown service.Display messages233On-board computer and displaysBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 233Z

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.
Seat belt
ProblemPossible causes/consequences and M Solutions7
After starting the
engine, the red seat
belt warning lamp lights
up for 6 seconds.The seat belt warning lamp reminds the driver and front passenger
to fasten their seat belts.XFasten your seat belt ( Y page 54).7
After starting the
engine, the red seat
belt warning lamp lights
up. In addition, a
warning tone sounds
for up to 6 seconds.GRisk of injury
The driver's seat belt is not fastened.
XFasten your seat belt ( Y page 54).
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 54).
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 cluster237On-board computer and displaysBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 237Z

Safety systemsProblemPossible causes/consequences and M Solutions!
The yellow ABS warning
lamp is lit while the
engine is running. GRisk of accident
ABS (Anti-lock Brake System) is deactivated due to a malfunction.
Therefore, BAS (Brake Assist), ESP ®
(Electronic Stability Program),
EBD (Electronic Brake-force Distribution) and PRE-SAFE ®
are also
deactivated.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XVisit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic
transmission, will not be available.
!
The yellow ABS warning
lamp is lit while the
engine is running.GRisk of accident
The on-board voltage is too low. ABS has been deactivated due to
undervoltage.
Therefore, ESP ®
, BAS and PRE-SAFE ®
are also deactivated.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XSwitch off consumers that are not required, e.g. the rear window
defroster or interior lighting.
ABS will be available again as soon as the vehicle's on-board
electrical system voltage increases.
If the warning lamp is still on:
XHave the battery and alternator checked at a qualified specialist
workshop.!
The yellow ABS warning
lamp is lit while the
engine is running.Self diagnosis is not yet complete.XCarefully drive a suitable distance making slight steering
movements at a speed above 12 mph (20 km/h).Warning and indicator lamps in the instrument cluster239On-board computer and displaysBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 239Z

ProblemPossible causes/consequences and M Solutionsd
The yellow ESP ®
warning lamp is lit while
the engine is running.GRisk of accident
ESP ®
and ESP ®
trailer stabilization are deactivated. ESP ®
will not
stabilize the vehicle if it starts to skid or if a wheel starts to spin.
XReactivate ESP ®
.
Exceptions: ( Y page 68).XAdapt your driving style to suit the road and weather conditions.
If ESP ®
cannot be activated:
XHave ESP ®
checked at a qualified specialist workshop.d
The yellow ESP ®
warning lamp is lit while
the engine is running.GRisk of accident
ESP ®
is 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.
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XVisit a qualified specialist workshop.+
The red SRS warning
lamp is lit while the
engine is running. GRisk of injury
The restraint systems are malfunctioning. The air bags or
Emergency Tensioning Devices 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.
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EngineProblemPossible causes/consequences and M Solutions! (USA only)
; (Canada only)
The yellow engine
diagnostics 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 gasoline engines)
The emission limit values may have been exceeded and the engine
may be breaking in emergency mode.XHave the vehicle checked as soon as possible at a qualified
specialist workshop.
i In some states, you are required to visit a qualified specialist
workshop as soon as the yellow engine diagnostics warning
lamp lights up due to the relevant applicable legislation. If
necessary, check whether this is the case in the state you are
in.
! (USA only)
; (Canada only)
The yellow engine
diagnostics warning
lamp lights up while the
engine is running.The 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.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.Vehicles with a diesel engine: the fuel tank has been run
completely dry and the engine will not start. There is air in the fuel
system ( Y page 164).The yellow reserve fuel
warning lamp lights up
while the engine is
running.The fuel level has fallen below the reserve range.
The fuel tank must be filled at least to the reserve fuel level to
prevent impairment to the running of the engine.XRefuel at the nearest gas station.242Warning and indicator lamps in the instrument clusterOn-board computer and displays
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XPull release lever : on 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.
XReach into the gap, pull hood catch
handle ; up and lift the hood.
Closing the hood
GWarning
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
Depending on the driving style, the vehicle
consumes up to 0.9 US qt (0.8 l) of oil over a
distance of 600 miles (1000 km). The oil
consumption may be higher than this when
the vehicle is new or if you frequently drive at
high engine speeds.
When checking the oil level:
R park the vehicle on a level surface.
R the engine should be switched off for at
least five minutes if the engine is at normal
operating temperature.
R the engine should be switched off for at
least 30 minutes if it is not at normal
operating temperature (i.e. if you only start
the engine briefly).
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Checking the oil level using the oil
dipstick
Example: gasoline engine
Example: diesel engine
XPull oil dipstick : out of the dipstick guide
tube.
XWipe off oil dipstick :.XSlowly insert oil dipstick : into the
dipstick guide tube to the stop, and take it
out again.
The oil level is correct if the level is between
MIN mark = and MAX mark ;.
XAdd oil if necessary.
Adding engine oil
HEnvironmental note
When adding oil, take care not to spill any. If
oil enters the soil or waterways, it is harmful
to the environment.
! Only use engine oils and oil filters which
have been approved for vehicles with a
service system. A list of the engine oils and
oil filters that have been tested and
approved according to the Mercedes-Benz
specifications for service products can be
found on the Internet at http://
www.mbusa.com (USA only). Further
information on tested and approved engine
oils and oil filters can be obtained from any
authorized Mercedes-Benz Center.
The following causes engine failure or
damage to the exhaust system:
Rusing engine oils and oil filters that are
not specifically approved for the service
system
Rreplacing the engine oil and oil filter later
than the specified replacement interval
required by the service system
Rusing engine oil additives
Example: engine oil cap
XTurn cap : counter-clockwise and remove
it.
XAdd the amount of oil required.
Fill carefully to the maximum mark on the oil
dipstick.
iThe difference in quantity between the
MIN mark and the MAX mark on the
dipstick is (depending on the engine)
approximately 1.6 to 2.1 US qt. (1.5 to 2 l).
! Do not add too much oil. If the oil level is
above the MAX mark on the dipstick, too
much oil has been added. This can lead to
damage to the engine or the catalytic
converter. Have excess oil siphoned off.
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