2012 MERCEDES-BENZ M-Class check engine light

Useful
information
i This
Operat or'sManual describesall
models andallstan dard andoption al
equipment ofyour vehicle available atthe
time ofpublication ofthe Operat or's
Manual. Country-specificdiffer encesare
possible. Pleasenotethat your vehicle may
not beequipped withallfeature s
descr ibed. Thisalso applies tosafet y-
related systemsand func tions. i
Please
readtheinfor mation onqualified
specialist workshops(Ypage 25). Occupant
safety Overview
ofoccupant safety
In this section, youwilllearn themost
import antfactsabout therest raint system
compo nentsof the vehicle.
The restraint system consists of:
R seat belts
R child restraint system s
R LATCH -type (ISOF IX)child seatanchors
Addit ional protection isprovided by:
R SRS (Supplemen talRestrain tSyst em)
R PRE -SAF E®
R Airb ag syst emcompo nentsw ith:
- PAS SENGER AIRB AG OFF indicator lamp
- fro nt-pa ssenge rseat with Occupant
Classification System(OCS)
The differen tairbag systems work
indep endently of each other.The protective
func tionsof the syst emwork incon junction
with each other.Not allair bags aredeployed
in an acc ident . G
WARN
ING Modif
ications toor work impro perly
con duct edon rest raint systemcom pone nts
or the irwirin g,as well astam perin gwith
int erc onn ectedelect ronicsyst ems, canlead to
the rest raint systems nolong erfunc tioning
as intende d.
Air bags orEm ergen cyTens ionin gDev ices
(ETD s),for exam ple,could deploy
inadv ertent lyor fail todeploy inacc ident s
altho ughthedecele ration threshold forair
bag deploymen tisexceeded. Therefore,
never modify therestraint systems. Donot
tamper withelectronic component sor their
software. i
See
"Children inthe vehicle"
(Y page 54)formore information on
infants andchildren traveling withyouin
the vehicle andrestraints forinfants and
children. SRS
(Supplemental RestraintSystem)
Introduction SRS
consists of:
R the 6 SRSwarning lamp
R air bags
R air bag cont rolunit (with crash sensors)
R Emergenc yTensioning Devicesforthe
front seatbelts andtheouter seatbelts in
the rear
R belt force limiters
SRS reduces therisk ofoccupants coming
into contactwith thevehicle's interiorinthe
event ofan accident. Itcan also reduce the
effect ofthe forces towhich occupants are
subjected duringanaccident.
SRS warning lamp SRS
function sare checked regularlywhen
you switch onthe ignition andwhen the
engine isrunning. Therefore, malfunctions
can bedetected ingood time.
The 6 SRSwarning lampinthe instrument
cluster lightsupwhen theignition isswitched
on. Itgoes outnolater thanafew seconds
after theengine isstarted. 38
Occ
upant safetySafety

Useful
information
i This
Operat or'sManual describesall
models andallstan dard andoption al
equipment ofyour vehicle available atthe
time ofpublication ofthe Operat or's
Manual. Country-specificdiffer encesare
possible. Pleasenotethat your vehicle may
not beequipped withallfeature s
descr ibed. Thisalso applies tosafet y-
related systemsand func tions. i
Please
readtheinfor mation onqualified
specialist workshops(Ypage 25). Sma
rtKey Impor
tant safet ynotes G
WARN
ING When
leaving thevehicle, alwaysremovethe
Smart Keyfrom theignit ionlock .Always take
the Smart Keywith youand lock thevehicle.
Do not leave children unsuperv isedinthe
vehicle, evenifthey aresecured inachild
rest raint system ,and donot give them acces s
to an unlock edvehicle. Achild's unsupervised
access toavehicle couldresult inan accident
and/or serious personal injury.Theycould:
R injure themselves onvehicle parts
R be seriously orfatally injured byextrem e
heat orcold
R injure themselves orhave anaccident with
vehicle equipment thatmay stillbein
operation evenaftertheSmartKey has
been removed fromtheignition, suchasthe
seat adjustment ,steering wheel
adjustment ormemory function.
If children openadoor, theycould cause
severe oreven fatalinjury toother persons; if
they getout ofthe vehicle, theycould injure
themselves whendoing soorbe seriously or
even fatally injured byany passing traffic.
Do not expose thechild restraint systemto
direct sunlight. Thechild restraint system's
metal parts, forexample, couldbecome very hot,
andachild could beburned onthese
parts. G
WARNING If
akey ring istoo heavy ortoo large, the
weight actingonthe key could cause itto turn
in the ignition lockorcatch onthe steering
wheel. Thiscould cause theengine tobe
switched offsuddenly. Youcould losecontrol
of the vehicle andcause anaccident. Donot
attach anyheavy orlarge keyrings tothe key
that isinserted inthe ignition. General
notes
If you cannot lockorunlock thevehicle with
the SmartK ey,either thebattery inthe
SmartK eyisdischarged, theSmartK eyis
faulty orthe starter battery isdischarged.
X Check thebattery inthe SmartK eyand
replace itifnecessary (Ypage 76).
X Unlock thedriver's doorusing the
mechanical key(Ypage 80).
X Lock thevehicle usingthemechanical key
(Y page 80).
X Have thestarter battery andthebattery
cont acts check edataqual ified specialist
workshop.
If the SmartK eyisfaulty, contactRoadsi de
Assistanc eor aqual ified specialist workshop. Smar
tKeyfunctions
General notes i
USA
only:
This device complies withPart15ofthe
FCC Rules. Operation issubject tothe
following twocondition s:
1. This device maynotcause harmful
interfer ence,and
2. this device mustaccept anyinterfer ence
received, includinginterferencethatmay
cause undesired operation. 72
Smar
tKeyOpening/closing

Problem Possible
causes/co nsequences andM Solutions
The
engine cannot be
started usingthe
SmartK ey. The
on-board voltageistoo low.
X Switch offnon- essential consumers, e.g.seat heating orinterior
lighting, andtrytostart theengine again.
If this does notwork:
X Check thestarter battery andcharge itifnecessary
(Y page 338).
or
X Jump-start thevehicle (Ypage 341).
or
X Consult aqual ified specialist workshop. The
engine cannot be
started usingKEYLE SS-
GO. TheSmartK eyisin
the vehicle. Ad
oor isopen. Therefore, theSmart Keycann otbe detect edas
easily .
X Close thedoor andtrytostart thevehicle again. There
isinter ferenc efrom apowerful sourceofradio waves.
X Start yourvehicle withtheSmart Keyinthe ignition lock. Doors
Import
antsafety notes G
WARNIN
G When
leaving thevehicle, alwaysremove the
Smart Keyfrom theignition lock.Always take
the Smart Keywith youand lock thevehicle.
Do not leave children unsupervised inthe
vehicle, evenifthey aresecured inachild
restraint system,anddonot give them access
to an unlocked vehicle.Achild's unsupervised
access toavehicle couldresult inan accident
and/or serious personal injury.Theycould:
R injure themselves onvehicle parts
R be seriously orfatally injured byextrem e
heat orcold
R injure themselves orhave anaccident with
vehicle equipment thatmay stillbein
operation evenaftertheSmartKey has
been removed fromtheignition, suchasthe
seat adjustment ,steering wheel
adjustment ormemory function. If
children openadoor, theycould cause
severe oreven fatalinjury toother persons; if
they getout ofthe vehicle, theycould injure
themselves whendoing soorbe seriously or
even fatally injured byany passing traffic.
Do not expose thechild restraint systemto
direct sunlight. Thechild restraint system's
metal parts, forexample, couldbecome very
hot, andachild could beburned onthese
parts. G
WARNING Do
not carry heavy orhard object sin the
passenger compartmen tor cargo
compartmen tunle ssthey arefirmly secu red
in place .
Unse curedorimp roperlypo sitio ned cargo
incre ases achi ld's ris kof inju ryinthe event
of
R stro ngbra king maneu vers
R sudd en cha nges ofdirecti on
R an acci dent 78
Do
orsOpening/closing

X
To switcho ff:set the rocker switch tothe
| position.
The interior lighting automatical lyswitches
on ifyou :
R unlock thevehicl e
R open adoor
R remove theSmartKey fromtheignitio nlock
The interior lightisactivated forashort while
when theSmart Keyisremoved fromthe
ignition lock.Youcanactivate thisdelay ed
switch- offusing theon-board computer
(Y page 235).
Manua linterior lighting control X
To switch thefront interior lighting on:
set the rock erswitch tothe c position.
X To switch thefront interior lighting off:
set the rock erswitch tothe | position.
X To switch therear interior lighting on/
off: press theu button .
X To switch thereading lampson/off:
press thep button . Crash-
responsive emergency lighting
The interior lighting isactivated automatically
if the vehicle isinvolved inan accident .
X To switch offthe crash- responsive
emergency lighting:pressthehazard
warning lampbutton .
or
X Lock andthen unlock thevehicle usingthe
Smart Key. Replacing
bulbs Import
antsafety notes
Xenon bulbs If
your vehicle isequipped withXenon bulbs,
you can recogn izethis bythe following: the
cone oflight from theXenon bulbsmoves
from thetop tothe bottom andback again when
youstart theengine. Forthis tobe
observed, thelights mustbeswitched on
before startingthe engine. G
DANGER Xenon
bulbscarryahigh voltage. Youcould
get anelectric shockandbeseriously oreven
fatally injured ifyou touch theelectric
cont acts onXenon bulbs.Therefore, never
remove thecover fromXenon bulbs.
Do not change Xenonbulbsyourself, buthave
them replaced ataquali fiedspecialist
workshop whichhasthenecessary specialist
knowledge andtools tocarry outthework
required.
Mercedes-B enzrecommen dsthat youusean
authorized Mercedes-B enzCenter forthis
purpose. Inparticular, workrelevant tosafety
or on safety-related systemsmustbecarried
out ataquali fiedspecialist workshop.
Bulbs andlamps areanimportant aspectof
vehicle safety.Youmust therefor emake sure
that these functioncorrec tlyatall times.
Have theheadlamp settingcheck edregularly .
Other bulbs There
arebulbs otherthantheXenon bulbs
that youcann otreplace. Replaceonly the
bulbs listed (Ypage 115). Havethebulbs that
you cann otreplace yourself changed ata
quali fiedspecialist workshop.
Mercedes-B enzrecomm endsthatyouusean
authorized Mercedes-B enzCenter forthis
purpose. Inparticular, workrelevant tosafety
or on safety-related systemsmustbecarried
out ataquali fiedspecialist workshop.
If you require assistance changingbulbs,
consult aquali fiedspecialist workshop.
Do not touch theglass tubeofnew bulbs with
your bare hands. Evenminor contamination
can burn intotheglass surface andreduce
the service lifeofthe bulbs. Always usealint-
free cloth oronly touch thebase ofthe bulb
when installing.
Only usebulbs ofthe correc ttype. 114
Rep
lacingbul bsLights an dwindshield wipers

Smar
tKeypositions
Smar tKey g
Toremove theSmartK ey
1 Power supply forsome consumers, such
as the windshield wipers
2 Ignition (powersupplyforallconsumers)
and drive position
3 Tostart theengine
As soon asthe ignition isswitched on,allthe
indicator lampsinthe instrumen tcluster light
up. Ifan indic atorlamp doesnotgoout after
the engineisstart ed orifit light sup while the
vehic leisin mot ion, see(Ypage 271).
If the SmartKey isin posit ion0in the ignit ion
lock foranext ende dperiod oftim e,itcan no
long erbe turned inthe ignit ionlock .The
steering isthen locked. Tounlock, remove the
SmartK eyand reinsert itinto theignition lock.
The steering islocked whenyouremove the
SmartK eyfrom theignition lock.
X Remove theSmartK eywhen theengine is
switched off.
The starter battery couldotherwise be
discharged.
If you cannot turntheSmartK eyinthe ignition
lock, thestarter battery maynotbecharged
sufficiently.
X Check thestarter battery andrecharge itif
necessary (Ypage 340).
or
X Jump-start thevehicle (Ypage 341). i
The
SmartK eycan beturned inthe
ignition lockeven ifit is not thecorrect
SmartK eyfor the vehicle. Theignition isnot
switched on.The engine cannot bestarted.
KEY LESS-GO General
informat ion
Vehicles withKEYLE SS-GO are equipp edwith
aS martKey featuringanintegrated KEYLESS-
GO function andadetacha bleStart/St op
button.
The Start/St opbutton mustbeinserted inthe
ignitio nlock andtheKEYLESS-GO keymust
be inthe vehicl e.
Pressi ngthe Start/St opbutton severaltimes
in successi oncorrespond sto the differe nt
SmartKey positions inthe ignitio nlock. This
is only thecase ifyou arenot depressing the
brake pedal.
If you depress thebrake pedalandpress the
Start /Stopbutton ,the engine starts
immediately.
The Start /Stopbutton canberemoved from
the ignition lock.Then, youcan insert the
Smart Keyinto theignition lock. i
You
donot have toremove theStart /Stop
button fromtheignition lockwhen you
leave thevehicle. However, youshould
alwa ystake theSmart Keywith youwhen
leaving thevehicle. Thevehicle canbe
start edwith theStart /Stopbutton andthe
electric alequipment canbeoperated while
the Smart Keyisin the vehicle. Driving
139Driving and parking Z

Problems
withtheengine Problem Possible
causes/co nsequences andM Solutions
The
engine doesnot
start. Thestarter motor
can beheard. R
There isamalfunction inthe engine electron ics.
R There isamalfunction inthe fuel supply .
X Try tostart theengine again(Ypage 140). Avoid excessively
long andfrequent attemptsto start theengine asthese willdrain
the battery.
If the engine doesnotstart after several attempt s:
X Consult aqual ified specialist workshop, e.g.anauthorized
Mercedes-B enzCenter. The
engine doesnot
start. Youcannot hear
the starter motor. The
on-board voltageistoo low because thebattery istoo weak
or discharged.
X Jump-start thevehicle (Ypage 341).
If the engine doesnotstart despite attemptsto jump-st artit:
X Consult aqual ified specialist workshop, e.g.anauthorized
Mercedes-B enzCenter. The
starter motorwasexposed toathermal loadthatwastoohigh.
X Allow thestarter motortocool down forapproximately two
minutes.
X Try tostart theengine again.
If the engine stilldoes notstart:
X Consult aqual ified specialist workshop, e.g.anauthorized
Mercedes-B enzCenter. The
engine isnot
running smoothly and
is misfiring. There
isamalfunction inthe engine electron icsoramechanical
componen tof the engine management system.
X Only depress theaccelerator pedalslightly.
X Have thecause rectifiedimmediately ataqual ified specialist
workshop, e.g.anauthorized Mercedes-B enzCenter.
Otherwise, non-combusted fuelmay getinto thecatalytic
conv erter anddamage it. The
coolant
temperature gauge
shows avalue above
248 ‡(120 †). The
coolant levelistoo low. Thecoolant istoo hotand theengine
is no longer beingcooled sufficiently.
X Stop assoon aspossible andallow theengine andthecoolant
to cool down.
X Check thecoolant level(Ypage 315). Observe thewarning
notes asyou dosoand add coolant ifnecessary. Driving
143Driving and parking Z

:
Toopen thefuel filler flap
; Toinsert thefuel filler cap
= Fuel type
? Tire pressure table
Opening X
Switc hoff the engine.
X Remove theSmart Keyfrom theignition
lock.
KEYLE SS-GO: open thedriver’s door.This
switches theignition toposition 0,which
correspon dstohaving removed the
Smart Key.Thedriver’s doorcanbeclosed
again.
X Press thefuel filler flapinthe direction of
arrow :.
The fuel filler flapswings up.
X Turn thefuel filler capcount er-clockwise
and remove it.
X Insert thefuel filler capinto theholder
bracket onthe inside offiller flap;.
X Completely insertthepump nozzleinto the
filler neck andrefuel.
X Only fillthe tank untilthepump nozzle
switches off.
! Overfilling thefuel tank could damage the
fuel system. Closing X
Replace thefuel filler capand turn it
clock wise. Thefuel filler capaudibl y
engages.
X Close thefuel filler flap. i
If
you drive withthefuel filler capopen,
reserve fuelwarning lamp8 flashes. In
addition, the; Check Engine warning
lamp maylight up.Am essage appears in
the multifunc tiondisplay (Ypage 257).
For furth erinfor mation onwarning and
indicat orlamps inthe instrument cluster,
see (Ypage 276). Refueling
151Driving and parking Z

Limi
tedbraking performa nce onsalt -
tr eat edroa ds G
WAR
NING The
layer ofsalt ontheb rake discs andthe
brake pads/linings maycauseadelay inthe
brakin geffec t,resultin gin asignific antly
longer brakingdistanc e,which couldleadto
an acciden t.
To avoid thisdanger, youshould:
R occ asionally brakecarefully, without
puttin gother roadusers atrisk, when you
are driving onsalted roads. Thishelps to
remov eany salt that may have startedto
build upon the brake discsandthebrake
pads/linin gs.
R maint ainagreater distancetothe vehicle
ahead anddrive withparticular care.
R carefully applythebrakes atthe end ofa
trip and immediately aftercommen cinga
new trip,sothat saltresidues areremoved
from thebrake discs.
Servicing thebrakes !
Ifthe red brake warning lamplights upin
the instr ument cluster andyouhear a
warning tonewhile theengine isrunnin g,
the brake fluidlevel maybetoo low.
Observe additional warningmessages in
the multifunct iondisplay .
The brake fluidlevel maybetoo low due to
brake padwear orleaking brakelines.
Have thebrake system checked
immediately. Thiswork should becarried
out atan authorized Mercedes-B enz
Center.
All check sand mainten ancework onthe
brake system mustbecarried outata
quali fiedspecialist workshop only.Have this
work carried outatan authorized Mercedes-
Benz Center.
Have thebrake padsreplaced andthebrake
fluid renewed ataquali fiedspecialist
workshop, e.g.anauthorized Mercedes-B enz
Center. G
WARNING If
brake padsorbrake fluidother thanthose
recommen dedareused, thebraking
properties ofthe vehicle canbedegraded to
an exten tthat safe braking issubstantially
impaired. Thiscould result inan accident.
! Afunct ionorperformance testshould
only becarried outona2 -axl e
dy nam ome ter.Ifyo uar eplanni ngtohave
the vehicleteste don such ady nam ome ter,
conta ctan author izedMer cedes-B enz
Ce nter toobtainfu rthe rinfo rma tionfir st.
Othe rwise, youcou ldda ma gethe drive
trai nor the brakesystem .
! Asthe ESP ®
sy stem opera tes
au toma tically, the engineand theigniti on
mu stbe switch edoff (Sma rtKeyin po sitio n
0 or 1in the igniti onlock orStar t/Stop
bu tton inpo sitio n0 or 1) wh ile the electri c
pa rking brakeisbe ing teste don abra ke
dy nam ome ter(ma ximu m10secon ds).
Brak ingtrigger edautomatic allybyESP®
may seriously damagethebrake system.
If your brake system issubject onlyto
moderate loads,youshould testthe
func tionality ofyour brakes atregular
int ervals bypressing firmlyonthe brake pedal
at high speeds. Thisimproves thegrip ofthe
brake pads. G
WARN
ING Make
surethatyoudonot endanger other
road users whenyouapply thebrakes.
You canfind adescript ionofBrak eAssist
(BAS )on (Ypage 61)orofBA SPLUS on
(Y page 62). 160
Driving
tipsDriving and parking