ESP MERCEDES-BENZ M-Class 2012 W166 Service Manual

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

Windshi
eldwipers Swi
tchin gthe windshie ldwipers on/
off G
WARNING Wip
erbla des arecomponents thataresub ject
to wea rand tea r.Re place thewipe rb lades
twic eayear, preferably inthe sprin gand fall.
Oth erwise thewindows willnotbewiped
proper ly.As aresult ,you may notbeable to
obser vesurro undin gtraffic condition sand
could cause anacc ident .
! Donot operat ethe windsh ieldwipers
when thewindsh ieldisdry, asthis could
damage thewiper blades. Moreover,dust
that hascollec tedonthe windsh ieldcan
scr atc hthe glass ifwiping takesplace when
the windsh ieldisdry.
! Ifthe windsh ieldwipers leavesmear son
the windsh ieldafterthe vehic lehas been
washed inan autom aticcarwash, waxor
oth erresidues maybethe reason forthis .
Clean thewindsh ieldusing washer fluid
aft erwashing thevehic lein an autom atic
car wash. Combin
ationswitch
1 $ Winds hieldwipers off
2 Ä Inter mit ten twipe, low7
3 Å Inter mit ten twipe, high8
4 ° Continuous wipe,slow
5 ¯ Continuous wipe,fast B
í Single wipe
C î Towipe withwasher fluid
X Swit chon the ignit ion.
X Turn thecom binat ionswitc hto the
appropr iateposit ionorpress thebutt onon
the side.
! Inter mit ten twiping withrainsensor: due
to optic alinf luenc esand thewindsh ield
becom ingdirtyin dry weather condition s,
the windsh ieldwipers maybeact ivate d
inadv ertent ly.This could thendamage the
wind shieldwiper blades orscrat ch the
wind shield.
For this reas on,you should always switch
off thewind shieldwiper sin dry weat her.
In theÄ orÅ position,theappro priate
wipin gfrequen cyisset auto maticall y
acc ording totheint ensityof therain .In
th eÅ position,therain sensor ismor e
sen sitive than intheÄ position,caus ing
th ewind shieldwiper sto wipe more
fr equen tly. Swit
ching therea rwindow wiperon/
off Combin
ationswitch
: è Rearwindow wiperswitch
2 b Towipe withwasher fluid
3 ° Toswitc hon intermit tentwiping
7 Rain sensorset tolow sens itivity.
8 Rain sensorset tohigh sensitivity. 118
Wind
shield wipersLights and windshield wipers

X
Remo vetheSm artKey from theign ition
loc k.
X Fo ldwiper arm:away from therear
win dow untilit en gage s.
X Pos ition wiper blade;atarig ht ang leto
wiper arm:.
X Ho ldwiper arm:and presswiper
blade ;inthedir ection ofthearr ow until
it rel ease s.
X Remo vewiper blade;.
Inst alling thewipe rblad e
X Place newwiper blade;ontowiper
arm :.
X Hold wiper arm:and press wiper
blade ;inthe opposit edirec tiontothe
arrow untilit engage s.
X Make surethatwiper blade;isseated
cor rectly.
X Posit ionwiper blade;parallel towiper
arm :.
X Fold wiper arm:back ontothe rear
window. Problem
swith thewindshield wipers
Th ewindshield wipersareobstr ucted Leaves
orsno w,for examp le,may be
obst ructingthe windsh ieldwiper movement.
The wiper motorhas been deact ivated . X
For safet yreason s,you should removethe
Smar tKey from theignit ionlock .
or
X Swit choff the engin eusing theStart/ Stop
butt onand open thedriver 'sdoor.
X Remove thecause ofthe obst ruction.
X Swit chthe windsh ieldwipers backon.
Th ewindshield wipersareinoper ative The
windsh ieldwiper driveismalfun ctionin g.
X Selec tanothe rwiper speed onthe
com binat ionswitc h.
X Have thewinds hieldwipers checkedata
qualified specialist workshop.
Th espr aynozz lesaremisa ligned The
winds hieldwasher fluidfromt hespray
nozz lesnolonger hitsthecent erofthe
windshield. Thespray nozzlesare misaligned.
X Have thespray nozzlesadjusted ata
qual ified specialist workshop. 120
Windshield
wipersLights and windshield wipers

norm
aland notasign tha tther eis a
ma lfunctio n. i
The
cooling with aird ehumidification
func tion uses refriger antR134a. This
coolant doesnotcontain
chlorof luorocarbon s,and therefore does
not damage theozon elayer.
Activating/d eactivating X
To activa te:press the¿/Á button.
The indicat orlamp inthe ¿/Á
button lightsup.
X To deactiva te:press the¿/Á
button .
The indicat orlamp inthe ¿/Á
button goesout.Thecooling withair
dehumidification function hasadelayed
switch -offfeature.
Problems withthecooling withair
dehum idificat ionfunction When
youpress the¿/Á button,the
indicat orlamp inthe button flashes three
times orremains off.You cannolonger switch
on the cooling withairdehumidification
func tion.
X Consult aqualified specialist workshop. Sett
ingclimat econtrol toaut omat ic G
WARN
ING If
you switch offthe cooling function,the
vehicle willnotbecooled whenweather
con ditions arewarm. Thewindows canfogup
more quickly. Window foggingmayimpair
visibility andendanger youand other s.
In automatic mode,thesettemper atureis
maint ained automatic allyatacon stan tlevel.
The system automatic allyregulates the
temper atureofthe dispensed air,the airflow
and theairdistribut ion.
Autom aticmode willachieve optimal
operation ifcooling withairdehumidification is
also activat ed.Ifdesired, coolingwithair
dehumidification canbedeactivat ed.
In the rear compart ment,you can also switch
climate control forthe rear seats toautomatic
mode usingtheà button .
X Turn theSmart Keytoposition 2in the
ignition lock.
X Set thedesired temperature.
X To activa te:press theà button .
The indicat orlamp inthe à button lights
up. Autom aticairdistribut ionand airflow
are activ ated. i
Autom
aticclimate control: when
automatic modeisactivat ed,you can
select aclimate modesetting
(Y page 129).
X To switch off:press the_ button .
or
X Press theI orK button .
The indicat orlamp inthe à button goes
out. Adju
sting theclimat emode settings
(AIR FLOW)
This function isonly available withautomatic
climate control.
The climate control settings areespecially
effec tiveathigh temper atures.
You canselect thefollowing climatecontrol
sett ings inautomatic mode:
FOCUS highairflow thatisset slightly
cooler
MED IUM medium airflow,standard setting
DIF FUS Elow airflow thatisset slightly
warmer andwith alower rateof
airflow Opera
tingtheclimate controlsystem
129Climate control Z

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). Br
eaking-in notes The
first 1000 miles (1500 km)
The more youlook after theengin ewhen itis
new, themore satisfiedyou willbewith its
perfor mancein the future.
R Driv eat varying vehiclespeeds andengin e
speeds forthe first 1000miles (1500km)
for this reason .
R Avo idovers trainingthe vehicle duringthis
period, e.g.drivin gat full throttle.
R Change gearingood time, atthe latest
when thetach omet erneedle is⅔o fthe
way tothe red area inthe tachomet er
displa y.
R Do not manually shifttoalower gearto
brake thevehicle.
R Only select shiftranges 3,2or 1when
driving slowly,e.g. inmountainous terrain.
Aft er1000 miles(1500 km),you can increase
the engine speedgraduall yand bring the
vehicle uptofull speed. i
You
should alsoobserve thesenoteson
runnin gin ifthe engine orparts ofthe drive
train onyour vehicle havebeen replaced. i
Always
observe therespect ivespeed
restr iction s. Driving
Import
antsafety notes G
WARNIN
G Make
sureabsolutely noobject sare
obstruct ingthe pedals' rangeofmovemen t.
Keep thedriver's footwell clearofall
obstacles. Ifthere areany floormats or
carpets inthe footwell, makesurethepedals
still have sufficient clearance.
During sudden drivingorbraking maneuvers
the object scould getcaught between the
pedals. Youcould thennolonger brakeor
accelerate. Thiscould leadtoaccident sand
injury. G
WARNIN
G On
slippery roadsurfaces, neverdownshift in
order toobtain braking action.Thiscould
result indrive wheel slipand reduced vehicle
cont rol.Your vehicle's ABSwillnotprevent
this type ofloss ofcont rol. G
WARNIN
G It
is dangerous toshift theautomatic
transm issionoutofparking position Por
neutral position Nifthe engine speedis
higher thanidlespeed. Ifyour footisnot firmly
on the brake pedal, thevehicle could
accelerate quicklyforward orinreverse. You
could losecontrolofthe vehicle andhit
someone orsomethin g.Only shiftintogear
when theengine isidling normally andwhen
your right footisfirmly onthe brake pedal.
! Warm upthe engine quickly. Donot use
the engine's fullperformanc euntil ithas
reached operating temperature.
Only shifttheautomatic transmission to
the desired driveposition whenthevehicle
is station ary.
Where possible, avoidspinnin gthe drive
wheels whenpulling awayonslippery
roads. Youcould otherwise damagethe
drive train. 138
DrivingDriving and parking

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

X
Insert Start/S topbutton :into ignition
lock ;. i
When
youinsert Start/S topbutton :
into ignition lock;,thesystem requiresa
detection timeofapp roximately two
seconds beforeyoucan useStart/S top
button :. Start/St
opbutton
= USA only
? Cana daonly
X Positio n0: ifStart/S topbutton :has not
yet been pressed ,this corresponds tothe
SmartKey beingremoved fromtheignition.
X Positio n1: press Start/S topbutton :
once.
You cannow activate thewindshi eld
wip ers, forexampl e. i
If
you press Start/S topbutton :twice
when inthis positio n,the powe rsupply is
deac tivat ed again .
X Pos ition 2(ign ition ):pre ssStart /S top
but ton: twice. i
If
you pressStart /S topbut ton: once
when inthis posi tion and thedriv er'sdoor
is open ,th epower supplyis deac tivat ed
again .
As soo nasthe ignition isswitched on,allthe
indicator lampsinthe instrument clusterlight
up. Ifan indicator lampdoesnotgoout after
the engine isstarted orifit lights upwhile the
vehicle isin motion, see(Ypage 271). Star
ting theengin e
Importa ntsafety notes G
WARNING Inhalation
ofexhaust gasishazardous toyour
health. Allexhaust gascont ains carbon
monoxide (CO),andinhaling itcan cause
unconsciousness andpossible death.
Do not run theengine inconfined areas(such
as agarage) whicharenot properly ventilated.
If you think thatexhaust gasfumes are
entering thevehicle whiledriving, havethe
cause determined andcorrect ed
immediately .Ify ou must driveunder these
condit ions,drive onlywith atleast one
window fullyopen atall times. i
Vehicles
withagasoline engine:the
catalytic converter preheats forupto30
seconds afteracold start.Durin gth is time,
th een gin esoun dmay bediff ere nt.
Aut oma tic trans mission X
Sh ift thetrans mis sion toposi tion P.
The trans mis sion position disp layinthe
mult ifunction disp laysho wsP
(Y page 145). i
You
canalso start theen gin ewhen the
tr ans mis sion isin posi tion N.
St artin gpr ocedu rewith theSm artKey X
To star tag asolineeng ine:turn the
SmartKey toposi tion 3in the ignition lock
(Y pag e139) andrelease itas soon asthe
engine isrunning.
X To start adiesel engine: turnthe
Smar tKey toposit ion2in the ignit ionlock
(Y page 139).
The % preglow indicatorlamp inthe
inst rumen tcluster lightsup.
X When the% preglo windic atorlamp
goes out,turnthe SmartK eytoposition 3
(Y page 139)andrelease itas soon asthe
engine isrunning. 140
DrivingDriving and parking

i
You
canstartthe engine without preglow
if the engine iswarm. i
You
canalso usethetouch-st artfunct ion.
To do this, turntheSmartK eytoposition 3
(Y page 139)andrelease itimmediately.
The engine thenstarts automatically .
Using KEYLESS-GO tostar tthe eng ine G
WARNING As
long asthe SmartKey isin you rvehicle, the
vehicle canbestart ed.Therefor e,never leave
children unattended inthe vehicle, asthey
could otherwiseacciden tallystart theengine.
When leaving thevehicle, alwaystake the
Smart Keywith youand lock thevehicle. Do
not leave children unattended inthe vehicle,
or with access toan unlock edvehicle. A
child's unsupervised accesstoavehicle could
result inan acciden tand/o rserious personal
injury. i
The
Start/ Stop button canbeused to
start thevehicle without insertingthe
Smart Keyintothe ignition lock.TheStart/
St op button mustbeinsert edinto the
ignition lockandtheSmart Keymust bein
the vehicle.
X Depress thebrake pedalandkeep it
depressed.
X To star tag asolineeng ine:press the
Start/Stop button(Ypag e139) once.
The engine starts.
X To start adiesel engine: presstheStart/
St op butt on(Ypage 139)onc e.
Preglow isact ivated andtheengin estar ts. Pulling
away
Autom atic transm ission G
WARN
ING It
is danger oustoshift theautomat ic
tr ansm ission outofparkin gposition Por
neutral position Nifthe engine speedis higher
thanidlespeed. Ifyour footisnot firmly
on the brake pedal, thevehicle could
accelerate quicklyforward orinreverse. You
could losecontrolofthe vehicle andhit
someone orsomethin g.Only shiftintogear
when theengine isidling normally andwhen
your right footisfirmly onthe brake pedal. i
It
is only possible toshift thetrans mission
from position Pto the desired position if
you depress thebrake pedal. Onlythenis
the parking lockreleased. Ifyou donot
depress thebrake pedal, youcan move the
DIRECT SELECT lever buttheparking lock
remains engaged.
X Depress thebrake pedalandkeep it
depressed.
X Shift thetrans mission toposition Dor R
(Y page 144).
X Relea sethe brake pedal.
X Carefully depresstheaccelerator pedal.
The electric parking brake(Ypage 156)is
automatically released.
The redF (USAonly)or! (Canada
only) indicator lampinthe instr ument
cluster goesout. i
The
vehicle lockscentrally once youhave
pulled away.The locking knobsinthe doors
drop down.
You canopen thedoors fromtheinside at
any time.
You canalso deactivate theautomatic
locking feature(Ypage 235). i
Upshifts
takeplace athigher engine
speeds afteracold start. Thishelps the
catalytic convertertoreach itsoperating
temperature morequickly.
Pulling awaywithatra iler To
ensure thatyoudonot rollbackwards
when pullingaway onanuphill slope, engage
the electric parking brake. Driving
141Driving 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

Aut
oma tic trans mission Imp
ortant safety notes G
WAR
NING It
is dan gerous toshif tthe automatic
transmission outofparking position Por
neutral position Nifthe engine speedis
higher thanidlespeed. Ifyour footisnot firmly
on the brake pedal, thevehicle could
accelerate quicklyforward orinreverse. You
could losecontrolofthe vehicle andhit
someone orsomething. Onlyshiftintogear
when theengine isidling normally andwhen
your right footisfirmly onthe brake pedal. G
WARNING Keep
inmind thatturning offthe engine alone
only willshift theautomatic transmission into
neutral position Nautomatically .
Always shifttheautomatic transmission into
park position Pbefore turning offthe engine.
Otherwise thevehicle couldrollaway which
could result inan accident and/orserious
personal injury. DIREC
TSELECT lever
Over view oftrans mis sion positions The
DIRECT SELECT leve rison the right ofthe
steering column. P
Park position withparking lock
R Reverse gear
N Neutral
D Drive i
The
DIRECT SELECTlever alwaysreturns
to its original position. Thecurrent
transmission positionP,R, Nor Dappea rs
in the transmission positiondisplay
(Y page 145)inthe multifunction display.
Engagin gpar kposit ionP X
Push theDI RECT SELECT lever inthe
direc tiono farrow P. i
The
automatic transmissi onshifts
au tomatical lyinto park position Pifyou
open thedrive r'sdoor when thevehicl eis
stationary ordrivi ngatvery lowspee d,and
the transmissi onisin posi tion Dor R.
! Ifthe engine speedis too high orthe
vehicl eis moving, donot shift the
au tomatic transmissi ondire ctly from Dto
R, from Rto Dor dire ctly toP.T he
automatic transmission couldotherwise be
damaged.
Engaging parkposit ionPau tom atically Park
positionPis autom atically engaged if:
R you switchoff theeng ineusin gth e
Sm artKey and remove theSm artKey, orif
you switchoff theeng ineusin gth eSt art /
St op butt onand open oneof thefron t
door s.
R theHOL Dfun ction (Ypage 179)or
DI STRO NICPLUS(Y page 169)brak es
your vehicle untilit is statio naryand atleast
on eof thefollo wing condition sis fulf illed:
- there isasyst emmalf unction.
- there isasev ere uphill ordown hillslope .
The electric park ingbrak eis then also
applied.
Engag ingreversegear R !
Onlyshif tthe automatic transmission to
R when thevehicle isstationary. 144
Automat
ictransmissionDriving and parking