
ProblemPossible causes/consequences andMSolutions
;
The yellow Check
Engine indicator
lamp is lit while
the engine is run-
ning.The exhaust gas aftertreatment is malfunctioning or an emission rel-
evant malfunction has occurred. This malfunction or defect can dam-
age the exhaust gas aftertreatment.
After the first message and under normal operating conditions, you
can drive on for up to approximately 500 mi (800 km). Then a warning
tone sequence sounds and the engine can only be started another 16
times.
XObserve the messages in the display.
XHave the exhaust gas aftertreatment checked immediately at a
qualified specialist workshop.
In some states it is legally prescribed that after the check engine indi- cator lamp lights up you must contact a qualified specialist workshop
immediately. Observe the legal requirements.
% If you turn the key
to position 2in
the ignition lock,
the yellow pre-
glow indicator
lamp remains lit
for approximately
1 minute. Or the
yellow preglow
indicator lamp
lights up for
approximately
1 minute while
the engine is run-
ning.At extremely low temperatures, the engine may not start.
There is a malfunction in the preglow system.
XHave any malfunction rectified at a qualified specialist workshop.
\ The yellow diesel
particle filter indi-
cator lamp is lit
while the engine
is running.The automatic regeneration of the diesel particle filter is not sufficient
or has malfunctioned.
XDrive at an engine speed above 2000 rpm until the diesel particle
filter indicator lamp goes out.
XIf the diesel particle filter indicator lamp does not go out after
approximately 20 minutes: have the malfunction rectified immedi-
ately at a qualified specialist workshop.
ÈThe yellow air fil-
ter indicator lamp
is lit while the
engine is running.The service limit for the air filter has been reached. The air filter is dirty.
XHave the air filter element replaced as soon as possible at a quali-
fied specialist workshop.
Indicator and warning lamps in the instrument cluster201
On-board computer and displays
Z

ProblemPossible causes/consequences andMSolutions
7
The red seat belt
warning lamp
lights up continu-
ously or flashes. A
warning tone may
also sound.The warning lamp is to remind you to fasten your seat belt.
XFasten seat belt (Ypage 42).
bWhen the key is
turned to position
2in the ignition
lock, the yellow
bulb warning
lamp lights up.One of the exterior lighting bulbs is faulty, with the exception of the
perimeter lamps and the trailer lighting.
iDepending on the equipment, the bulb failure indicator can fail for
all lamps with the exception of the turn signal lamps.
XReplace the faulty bulb as soon as possible (Ypage 86).
1 The yellow "door
open" indicator
lamp is lit while
driving.The vehicle is moving without all doors or the hood being closed.
XClose the doors or hood.
1The yellow "door
open" indicator
lamp is lit.The electrical step has retracted or extended only partially or not at all.
XMake sure there is sufficient free space for the electrical step.
XOpen or close the sliding door again.
XIf the electrical step still does not extend or retract fully, push the
step in manually (Ypage 67). Before stepping out, remind the pas-
sengers that the step is missing.
Ð The indicator
lamp for the
steering is lit
when the ignition
is switched on.The power assistance for the steering has malfunctioned. You need to
steer more forcefully.
XCarefully continue to a qualified specialist workshop and have the
steering checked immediately.
Indicator and warning lamps in the instrument cluster203
On-board computer and displays
Z

Checking the brake fluid level
XStop your vehicle as far away from traffic as
possible on level ground.
XSwitch off the engine.
XSecure the vehicle to prevent it from rolling
away.
XOpen the hood (Ypage 218).
XCheck the brake fluid level.
The brake fluid level is correct if the level is
between the MIN mark and MAX mark on
brake fluid reservoir:.
XClose the hood.
!If the brake fluid level in the brake fluid res-
ervoir has fallen to the MIN mark or below,
check the brake system immediately for
leaks. Also check the thickness of the brake
linings. Visit a qualified specialist workshop
immediately.
Do not add brake fluid. This does not correct
the malfunction.
Washer fluid
GWARNING
Windshield washer concentrate could ignite if it comes into contact with hot engine compo-
nents or the exhaust system. There is a risk of
fire and injury.
Make sure that no windshield washer con-
centrate is spilled next to the filler neck.
!Only use washer fluid that is suitable for
plastic lamp lenses, e.g. MB SummerFit or MB WinterFit. Unsuitable washer fluid could dam-
age the plastic lenses of the headlamps.
Example: washer fluid reservoir
Add windshield washer concentrate to the
washer fluid all year round. Observe the infor-
mation on washer fluid in the "Technical data"
section (
Ypage 284).
Adding washer fluid
XMix the washer fluid to the appropriate mixing ratio in a container beforehand.
XOpen the hood (Ypage 218).
XPull cap :on the washer fluid reservoir
upwards at the tab.
XAdd the premixed washer fluid.
XPress cap :onto the filler neck until it
engages audibly.
XClose the hood.
Fuel system
Draining the fuel filter
GWARNING
Fuel is highly flammable. Improper handling of
fuel creates a risk of fire and explosion.
Avoid fire, open flames, smoking and creating
sparks under all circumstances. Switch off the
ignition and auxiliary heating before carrying
out work to the fuel system. Always wear pro-
tective gloves.
HEnvironmental note
Dispose of the water-fuel mixture in an envi-
ronmentally responsible manner.
!When the :indicator lamp lights up,
drain the fuel filter with water separator
immediately. Otherwise, the engine may be
damaged.
224Engine compartment
Maintenance and care

cle is started as long as the malfunction
exists.
When the malfunction indicator is illuminated,the system may not be able to detect or signal
low tire pressure as intended. TPMS malfunc-
tions may occur for a variety of reasons,
including the mounting of incompatible
replacement or alternate tires or wheels on
the vehicle that prevent the TPMS from func-
tioning properly. Always check the TPMS mal-
function telltale after replacing one or more
tires or wheels on your vehicle to ensure that
the replacement or alternate tires and wheels
allow the TPMS to continue to function prop-
erly.
Vehicles with a tire pressure monitor are equip-
ped with sensors in the wheels that monitor the
tire pressure of all four tires. The tire pressure
monitor monitors the pressure in all four tires;
you set this pressure when you activate the tire
pressure monitor. The tire pressure monitor
warns you when the pressure drops in one or
more of the tires. The tire pressure monitor only
functions if the corresponding sensors are
installed on all wheels.
You should always adjust the tire pressure
according to the vehicle load. Restart the tire
pressure monitor if you change the tire pres-
sure.
The tire pressure monitor does not warn you if a
tire pressure is incorrect. Observe the notes on
the recommended tire pressure (
Ypage 250).
The tire pressure moni tor i
s not able to warn you
of a sudden loss of pressure, e.g. following pen- etration by a foreign object. In this event, brake
the vehicle until it comes to a standstill. Do not
carry out any sudden steering maneuvers.
The tire pressure monitor has a yellow h
warning lamp in the instrument cluster for indi-
cating pressure loss/malfunctions (USA) or
pressure loss (Canada). Depending on how the
warning lamp flashes or lights up, an underin-
flated tire or a malfunction in the tire pressure
monitor is displayed:
Rif the h warning lamp is lit continuously,
the tire pressure on one or more tires is sig- nificantly too low. The tire pressure monitor is
not malfunctioning.
RUSA only: if the hwarning lamp flashes for
60 seconds and then remains lit constantly,
the tire pressure monitor is malfunctioning.
Only vehicles with steering wheel buttons: the
on-board computer displays information on tire
pressure. After a few minutes of driving, the cur-
rent tire pressure of each tire is shown in the on-
board computer.
USA only: if the tire pressure monitor is mal-
functioning, it may be more than 10 minutes
before the malfunction is shown. The htire
pressure warning lamp flashes for 60 seconds
and then remains lit. When the malfunction has been rectified, the htire pressure warning
lamp goes out after a few minutes of driving.
The tire p
ressure values indicated by the on-
board computer may differ from those meas-
ured at a gas station with a pressure gage. The
tire pressures shown by the on-board computer
refer to those measured at sea level. At high
altitudes, the tire pressure values indicated by a pressure gage are higher than those shown by
the on-board computer. In this case, do not
reduce the tire pressures.
If radio transmitting equipment (e.g. wireless
headphones, two-way radios) is operated inside
the vehicle or in the vicinity of the vehicle, this
can interfere with the operation of the tire pres-
sure monitor.
Checking the tire pressure electroni-
cally (vehicles with steering wheel but-
tons)
Tire pressure display
254Tire pressure
Wheels and tires