Lights MERCEDES-BENZ R-Class 2012 W251 Workshop Manual

Display messagesPossible causes/consequences and M Solutions$ (USA
only) ! (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 messages217On-board computer and displaysZ

GWARNING
If the 42 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
Low Beam Left
or Low Beam RightThe left or right-hand low-beam headlamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Trailer Tail Lamp
Left or Trailer
Tail Lamp RightThe left or right-hand trailer tail lamp is faulty.XCheck whether you are permitted to change the bulb yourself.
or
XVisit a qualified specialist workshop.b
Trailer Turn
Signal Left or
Trailer Turn
Signal RightThe left or right-hand trailer turn signal lamp is defective.XCheck whether you are permitted to change the bulb yourself.
or
XVisit a qualified specialist workshop.b
Trailer Brake LampThe trailer brake lamp is defective.XCheck whether you are permitted to change the bulb yourself.
or
XVisit a qualified specialist workshop.b
Turn Signal Rear
Left or Turn Signal
Rear RightThe rear left-hand or rear right-hand turn signal is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.222Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutionsb
AUTO Light
InoperativeThe light sensor is defective.XVisit a qualified specialist workshop.
USA only:
XSwitch off the daytime running lamps in the on-board computer
( Y page 206).XSwitch the lights on and off using the light switch.b
Switch Off LightsThe lights are still switched on when you leave the vehicle. A
warning tone also sounds.XTurn the light switch to $ or à .
or
XIf the rear fog lamp is switched on: press the light switch in to
the stop.
Engine
Display messagesPossible causes/consequences and M Solutions+
Top Up Coolant See
Operator's ManualThe coolant level is too low.XAdd coolant, observing the warning notes when doing so
( Y page 285).XIf the coolant needs to be refilled 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.
Display messages225On-board computer and displaysZ

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 51).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 51).
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 51).
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.238Warning and indicator lamps in the instrument clusterOn-board computer and displays

EngineProblemPossible causes/consequences and M Solutions! (USA only)
; (Canada only)
The yellow Check
Engine warning lamp
lights up while the
ignition is switched on
with the engine
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 160).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.The yellow reserve fuel
warning lamp flashes
while the vehicle is in
motion.
In addition, the !
(USA only)/ ;
(Canada only) 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.244Warning and indicator lamps in the instrument clusterOn-board computer and displays

Driving systemsProblemPossible 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 (Y page 173) and the distance
warning signal ( Y page 68).
Tires
ProblemPossible causes/consequences and M Solutionsh
USA only:
The yellow tire pressure
monitor warning lamp
(pressure loss/
malfunction) is lit.GRisk of accident
The tire pressure monitor has detected a loss of pressure in at
least one of the tires.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XObserve the additional display messages in the multifunction
display.XCheck the tire pressure. If necessary, correct the tire pressure
( Y page 331).XIf necessary, change a wheel ( Y page 346).h
USA only:
The yellow tire pressure
monitor warning lamp
(pressure loss/
malfunction) flashes for
60 seconds and then
remains lit.The tire pressure monitor is defective.XObserve the additional display messages in the multifunction
display.XVisit a qualified specialist workshop.GWARNING
Each tire, including the spare (if provided), should be checked every other week when cold and
inflated to the inflation pressure recommended by the vehicle manufacturer on the Tire and
Loading Information placard on the driver's door B-pillar or, if available, the tire inflation pressure
label on the inside of the fuel filler flap. If your vehicle has tires of a different size than the size
Warning and indicator lamps in the instrument cluster245On-board computer and displaysZ

GWARNING
Any device that you connect must have a
suitable plug and meet U.S. standards. Never
pull at a cable to disconnect a plug from a
115 V AC power socket. Never use a damaged
connection cable. The 115 V AC power socket
must never be connected to another 115 V
AC power source. Do not use a converter with
an earthed plug for the 115 V AC power
socket. This could cause serious injury to you
and/or other people.
GWARNING
If the 115V AC socket is damaged or torn out
of the trim, do not use or touch the 115V AC
socket. Using a 115V AC socket that is
damaged or torn out of the trim could cause
serious personal injury to you and/or others.
115 V socket : provides an alternating
voltage of 115 V, so that small electronic
devices can be connected. These devices,
such as games consoles, chargers and
laptops, together should not consume more
than a maximum of 150 W.
Requirements for operation of these devices:
R the plug of the electronic device must be
inserted fully into 115 V power socket :.
R the maximum wattage of the device to be
connected must not exceed 150 W.
R the on-board power supply is within a
permissible volt range.
R the 12 V sockets in the rear and the cargo
compartment are operational
( Y page 267).
XOpen flap =.XInsert the plug of the electronic device into
115 V power socket :.
Indicator lamp ; lights up.
If indicator lamp ; does not light up,
consult the section on malfunctions.XTo turn off: disconnect the plug from 115 V
power socket :.
Ensure that you do not pull on the cord.XClose flap =.
Possible causes of malfunction:
R the on-board power supply is not within a
permissible volt range.
R the temperature of the DC/AC converter is
temporarily too high.
R some small electronic devices have a
constant nominal power of less than
150 W, but a very high inrush current.
These devices will not work. If you connect
such a device, 115 V power socket : will
not supply it with power.
If indicator lamp ; still does not light up,
contact a specialist workshop, e.g. an
authorized Mercedes-Benz Center.
mbrace
Important safety notes
! A license agreement must exist in order
to activate the mbrace service. Ensure that
your system is activated and ready for use,
and press the E MB Info call button to
register. If any of the steps mentioned is
not carried out, the system may not be
activated.
If you have questions about the activation,
contact one of the following telephone
assistance services:
R USA: Mercedes-Benz Customer
Assistance Center under
1-888-990-9007
R Canada: Customer Service at
1-888-923-8367
Features269Stowing and featuresZ

position for at least 25 seconds before
trying another position.XPress and hold transmitter button B on
garage door remote control A until
indicator lamp : lights up green.
Programming is complete if indicator
lamp : lights up or flashes green.XRelease transmitter button ;, = or ? on
the integrated garage door opener and the
transmitter button on garage door remote
control B.
If indicator lamp : lights up red:
XRepeat the programming procedure for the
transmitter button. When doing so, vary the
distance between the garage door remote
control and the rear-view mirror.
i If the indicator lamp flashes green after
successful programming, the garage door
system is operating on a rolling code. After
programming, you must synchronize the
garage door opener integrated in the rear-
view mirror with the receiver of the garage
door system.
Synchronizing the rolling code
Your vehicle must be within range of the
garage or gate opener drive. Make sure that
neither your vehicle nor any persons/objects
are present within the sweep of the door or
gate.
Observe the safety notes when performing
the rolling code synchronization.
XTurn the SmartKey to position 2 in the
ignition lock.XPress the programming button of the door
or gate drive (see the door or gate drive
operating instructions, e.g. under
"Programming of additional remote
controls").
i You now normally have 30 seconds to
initiate the next step.
XPress the previously programmed
transmitter button of the HomeLink ®integrated garage door opener repeatedly
in succession until the door opens.
The rolling code synchronization is then
complete.
Notes on programming the remote
control
Canadian radio frequency laws require a
"break" (or interruption) of the transmission
signals after broadcasting for a few seconds.
These signals may not therefore last long
enough for the integrated garage door opener
to recognize the signal during programming.
Comparable with Canadian law, some U.S.
garage door openers also have a built-in
"interruption".
If you live in Canada or have difficulties
programming the garage door opener
(regardless of where you live) when using the
programming steps (see above), proceed as
follows:
XPress and hold one of transmitter
buttons ; to ? of the integrated garage
door opener.
Indicator lamp : starts to flash yellow
after a short period.XRelease the transmitter button.XPress transmitter button B of the garage
door remote control and hold for two
seconds, then release for two seconds,
then press again and hold for two seconds.XRepeat this sequence on transmitter
button B of the garage door remote
control until indicator lamp : is green.
Repeat the process if indicator lamp :
turns red.XContinue with the other programming
steps (see above).
Problems when programming
If you are experiencing problems
programming the integrated garage door
opener on the rear-view mirror, take note of
the following instructions:
R check the transmission frequency of
garage door remote control A (usually
Features277Stowing and featuresZ

found on the reverse side of the remote
control).
The integrated garage door opener is
compatible with devices that can be
operated with units in a frequency range of
280 to 390 MHz.
R change the batteries in garage door remote
control A. This increases the probability
that garage door remote control A will
send a strong and precise signal to the
integrated garage door opener on the rear-
view mirror.
R when programming, hold garage door
remote control A at different distances
and angles from the transmitter button that
you are programming. Try different angles
at a distance between 2 and 12 inches (5
to 30 cm) or the same angle at varying
distances.
R if another remote control for the same
garage door drive is available, repeat the
same programming steps with this remote
control. Before you perform the steps of the
operation, make sure that there are new
batteries in the garage door remote
control.
R note that some remote controls only
transmit for a limited amount of time (the
indicator lamp on the remote control goes
out). Press the remote control button again
before it stops transmitting.
R align the antenna cable of the garage door
opener unit. This can improve signal
reception/transmission.
Opening/closing the garage door
Once programmed, the integrated garage
door opener will assume the function of the
garage door system's remote control. Please
also read the operating instructions for the
garage door system.
XTurn the SmartKey to position 2 in the
ignition lock.XPress transmitter button ;, = or ? in the
overhead control panel that you have
programmed to operate the garage door.
Garage door system with a fixed code:
indicator lamp : lights up green.
Garage door system with a rolling code:
indicator lamp : flashes green.
i
The transmitter will transmit a signal for
as long as the transmitter button is being
pressed. After a maximum of ten seconds,
transmission is terminated and indicator
lamp : flashes yellow. Press the
transmitter button again, if necessary.
Clearing the memory of the integrated
garage door opener on the rear-view
mirror
XTurn the SmartKey to position 2 in the
ignition lock.XPress transmitter buttons ; and ?.
The indicator lamp lights up yellow.XPress and hold transmitter buttons ;
and ? until the indicator lamp turns green.
i
Make sure that you clear the memory of
the integrated garage door opener before
selling the vehicle.
Compass
Calling up the compass
XPress the V or U button on the
multifunction steering wheel repeatedly
until the AIRMATIC/Compass menu
appears in the multifunction display.
The compass shows which direction the
vehicle is currently traveling in: N, NE , E , SE ,
S , SW , W or NW.278FeaturesStowing and features

XMake sure the vehicle is stationary and the
ignition is switched off.XTurn the SmartKey to position
2 (Y page 145) in the ignition lock.
Use the SmartKey instead of the Start/
Stop button on vehicles with KEYLESS-GO.XDepress and hold the brake pedal.XShift the automatic transmission to
position N.XRelease the brake pedal.XRelease the parking brake.XSwitch off the ignition and leave the
SmartKey in the ignition lock.
! Make sure that:
R the side windows and the sliding sunroof
are fully closed.
R the ventilation/heating is switched off
(the OFF button has been pressed).
R the windshield wiper switch is in position
0 .
Otherwise, the vehicle might be damaged.
After using an automatic car wash, wipe off
wax from the windshield and the wiper
blades. This will prevent smears and reduce
wiping noises caused by residue on the
windshield.
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
R trim 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
Care289Maintenance and careZ