engine MERCEDES-BENZ M-Class 2012 W166 Manual Online

!
Ifthe coolant temperature istoo high a
displa ymessage isshown.
If the coolant temperature risesabove
248 ‡(120 †),donot drive anyfurther as
this could damage theengine. Tachometer
The redband inthe tachometer indicatesthe
engine's overrevving range.
! Donot drive inthe overrevving range,as
this could damage theengine.
The fuel suppl yis interrupted toprotect the
engine whenthered band isreached. Outside
tempera turedisplay
The outside temperature displayis in the
multifunction display(Y page 224). G
WARNING The
outside temperature indicatorisnot
designed toserve asan ice-warning device
and istherefore unsuitablefor that purpose.
Indicated temperatures justabove the
freezing pointdonot guara nteethattheroad
surface isfree ofice. The road maystillbeicy,
especial lyin wooded areasoron bridges.
Changes inthe outside temperature are
displa yedafter ashort delay. Speedometer
withsegments
The segments inthe speedometer indicate
which speed rangeisavail able.
Cruise control(Ypage 167)activated:
The segments lightupfrom thestored speed
to the maximum speed.
DISTRONIC PLUS(Ypage 169)activated:
One ortwo segments inthe setspeed range
light up.
DISTRONIC PLUSdetects avehicle infront :The
segments betweenthespeed ofthe
vehicle infront andthestored speedlightup. Operating
theon-board computer
Overview The
on-board computer isactivated assoon
as you turn theSmartKey toposition 1in the
ignition lock.
You cancont rolthe multifunction displayand
the settings inthe on-board computer using
the buttons onthe multifunction steering
wheel. :
Multifunction display
; Toswitch onthe Voice Control System;
see theseparate operating instructions
= Right controlpanel
? Left controlpanel
A Back button Dis
plays andoperation
223On-board computer and displays Z

X
Press the: or9 button toselect the Display
UnitSpeed-/Od ometer funct
ion.
You willsee theselected setting: km or
miles .
X Press thea button tosave thesetting.
Selecting theperm anent display function
The Permanent
Display: funct
ionallows
you tochoose whether themultifunc tion
display alwaysshows theoutside
temperat ureorthe speed inkm/ h(USA) or
mph (Canada).
X Press the= or; button onthe
steerin gwheel toselect the Settings
menu.
X Press the: or9 button toselect the Instr.
cluster submenu.
X Press thea button toconf irm.
X Press the: or9 button toselect the Permanent
display funct
ion.
You willsee theselected setting Outside
Temperatu
re or Speedomet
er[km/h]: .
X Press thea button tosave thesetting.
Lights Switching
thedayt imerunning lampson/
off
This funct ionisnot availabl ein Canada.
If you have activat edthe Daytime Running
Lights: funct
ionand thelight switch isin the
c orà position, thedaytime running
lamps areswitched onautomatically during
the day when theengine isrunnin g.
In the dark, thefollowing alsolight up:
R the low-beam headlamps
R the parking lamps
R the taillamps
R the license platelamp
R the side marker lamps X
Press the= or; button onthe
steerin gwheel toselect the Sett. menu.
X Press the: or9 button toselect the Lights submenu.
X Press thea button toconf irm.
X Press the: or9 button toselect the Daytime
RunningLights: funct
ion.
You willsee theselected setting: Enabled
or Disabled .
X Press thea button tosave thesetting.
Switching AdaptiveHighbeam Assiston/
off
X Press the= or; button onthe
steerin gwheel toselect the Sett. menu.
X Press the: or9 button toselect the Lights submenu.
X Press thea button toconf irm.
X Press :or9 toselect the Adaptive
HighbeamAssist: funct
ion.
You willsee theselected setting: Enabled
or Disabled .
X Press thea button tosave thesetting.
Setting thebright nessofthe ambient
lighting
X Press the= or; button onthe
steerin gwheel toselect the Settings
menu.
X Press the: or9 button toselect the Lights submenu.
X Press the: or9 button toselect Ambient
light .
You willsee theselected setting.
X Press thea button toconf irm.
X Press the: or9 button toadjust the
brightn esstoany level from Off to Level
5 (bright).
X Press thea or% button tosave the
sett ing. 234
Menus
andsubmenusOn-board computer and displays

Setting
theambient lightingcolor
X Press the= or; button onthe
steering wheeltoselect the Settings
menu.
X Press the: or9 button toselect the Light submenu.
X Press thea button toconf irm.
X Press the: or9 button toselect the Ambient
lightcolor funct
ion.
X Press thea button toconf irm.
X Press the: or9 button toset the
color to SOLAR , NEUTRAL or POLAR .
X Press thea or% button tosave the
settin g.
Activating/deactivating surround
lighting andexterior lightingdelayed
switch-off
If you have activated the Lighting: funct
ion
and thelight switch isin the c orÃ
position, thefollowing functionsareactive
when itis dark:
R Surr ound lighting: theexterior lighting
remains litfor 40seconds afterunlocking
with thekey. Ifyou start theengine, the
surround lightingisswitched offand the
automatic headlampmode isactivated
(Y page 110).
R Exterior lightingdelayed switch-off: the
exterior lightingremains litfor 60seconds
after theengine hasbeen switched off.If
you close allthe doors, theexterior lighting
goes offafter 15seconds.
If you activate the Lighting: funct
ion,the
following lightupdepending onthe vehicle's
equipment:
R the parking lamps
R the daytime runninglamps
R the side marker lamps
R the surround lightinginthe exterior mirrors
X Press the= or; button onthe
steering wheeltoselect the Sett. menu.
X Press the: or9 button toselect the Lights submenu. X
Press thea button toconf irm.
X Press the: or9 button toselect the Locator
Lighting: funct
ion.
You willsee theselected setting: Enabled
or Disabled .
X Press thea button tosave thesettin g.
Deactivat ingdelay edswitch-of fofthe
exterior lightingtemporarily:
X Before leaving thevehicle, turnthe
SmartK eytoposition 0in the ignition lock.
X Turn theSmartK eytoposition 2in the
ignition lockandback toposition 0.
The exterior lightingdelayedswitch-off is
deactivated.
Delayed switch-off ofthe exterior lightingis
reactivated thenext time youstart the
engine.
Activating/deactivating theinterior
lighting delayed switch-off
If you activate the Interior
Lighting Delay funct
ion,theinterior lighting remains
on for 20seconds afteryouremove the
SmartK eyfrom theignition lock.
X Press the= or; button onthe
steering wheeltoselect the Settings
menu.
X Press the: or9 button toselect the Lights submenu.
X Press thea button toconfirm .
X Press the: or9 button toselect the Interior
LightingDelay: funct
ion.
You willsee theselected setting: Enabled
or Disabled .
X Press thea button tosave thesettin g.
Vehicle Activating/deactivating
theautom atic
door locking feature
If you select the Automatic
DoorLock: funct
ion,thevehicle iscent rally locked above
a speed ofaround 9mph(15 km/ h). Menus
andsubm enus
235On-board computer and displays Z

Disp
laymessa ges Poss
iblecauses/c onseq uences and M Solu
tions The
yello w! warning lamp lightsup. The redF (USA
on ly)/ ! (Canadaonly) indic ato rlamp flashes for
appro ximately10 sec onds aftertheelec tric park ingbrak ehas
been applied orrele ased. Itth en goes outorrem ains lit.
The electric park ingbrak eis malf unctionin g.
X Swit choff theign ition and turnit back on.
X En gage theelec tric park ingbrak e.
If it is no tp ossible toengage theelectric parking brake:
X Shift thetrans mission toP.
X Visit aquali fiedspecialist workshop.
If it is not possible torelease theelectric parking brake:
X Release theelectric parking brakeautomatically (Ypage 156).
If the electric parking brakestillcann otbe released:
X Consult aquali fiedspecialist workshop. The
yellow !warning lamplights up.When yourelease orapply
the electric parking brakemanually ,the red F (USA
only)/ !(Canada only)indicator lampflashes.
The electric parking brakeismalfunct ioning.Itis not possible to
apply theelectric parking brakemanually .
X Shift thetrans mission toP.
X Visit aquali fiedspecialist workshop. F(USA
only)!(Canada
only) Pkg
Brake Inoperative The
yellow !warning lamplights up.The redF (USA
only)/ !(Canada only)indicator lampflashes for
approximately 10seconds aftertheelectric parking brakehas
been applied orreleased. Itthen goes outorremains lit.
The electric parking brakeismalfunct ioning,e.g.because of
overvoltage orundervoltage.
X Remove thecause forthe overvoltage orundervoltage, e.g.by
charging thebattery orrestart ingthe engine.
X En gage orrelease theelectric parking brake.
If it remains impossible toapply orrelease theelectric parking
brake:
X Switch offthe ignition andturn itback on.
X En gage orrelease theelectric parking brake.
If the electric parking brakestillcann otbe released:
X Consult aquali fiedspecialist workshop. Display
messages
243On-board computer and displays Z

Disp
laymessa ges Poss
iblecauses/c onseq uences and M Solu
tions G
Tel
eAid Ino
perative US
Ao nly:one ormor eof the mainfunctio nsinthe mbr ace system
ar ema lfunctio ning.
Ca nad aonl y:one ormor eof the mainfunctio nsofthe TELEAI D
sy stem arema lfunctio ning.
X USA only:ha ve the mbr ace system checked ataq ualifi ed
spec ialist workshop.
X Canad aon ly: have theTE LE AIDs ystem checke dat aqualif ied
spe cialist wor kshop . PRE
-SAFE Ino
perative See Ope
rator'sMan ual G
Ri
sk ofinjury Im
por tant fun ction sofPRE-SAFE ®
have failed .Alloth erocc upant
safet ysyst ems, e.g.airbags, remain available.
X Visit aqualified specialist workshop immed iately. PRE-
SAFE Func
tion Curr
ently Limi
tedSee Oper. Manu
al G
Risk
ofacciden t PRE-
SAFE®
Br ake istem porar ilyinope rative if:
R the DISTRON ICPLUS coverinthe radiat orgrill isdirt y.
R the sensors inthe bumper sare dirty.
R its func tion isimpaired duetoheavy rainorsno w.
R the radar sensor syst emistem porar ilyinope rative, e.g. due to
elect romagnet icradiat ionemit tedbynear byTV orradio
st ation sor oth ersourc esofelect romagnet icradiat ion.
R the syst emisouts idethe operat ingtem perat urerang e.
R the on-board voltage istoo low.
PRE- SAFE®
Br ake isoperat ionalagain andthedisplay message
disappears if:
R the dirt (e.g.slush) drops awaywhile thevehic leisin mot ion.
R the syst emdete ctsthat thesensors arefully available again.
R the syst emiswithin theoperat ingtem perat urerang e.
If the display messagecontinues tobe displayed:
X Clean theDISTRON ICPLUS coverinthe radiat orgrill
(Y page 322).
X Clean thebumper s(Y page 322).
X Restar tthe engine.
X Wait untilthebattery issufficiently charged. Display
messages
245On-board computer and displays Z

Engine
Displ
aymes sage s Possib
lecau ses/cons equences andM Solu
tions +
Che
ckCoolant Lev
elSee Ope
rator'sMan ual The
coolant levelis toolow.
X Add coolant ,obse rving thewarn ingnoteswhen doingso
(Y page 315).
X Ifcoo lant needs tobe added moreoft en than usual, havethe
en gin ecoo lant systemcheck edataqualifie dspec ialist
work shop. G
WAR
NING Do
notspill antif reeze onhot engin eparts. Antifr eeze contains ethylene glycolwhich mayburn
if it comes intocon tact with hotengin eparts. Youcould beseriously burned.
! The coolant levelistoo low. Avoid makin glong journ eyswith toolittlecoolant inthe cooling
system. Theengin ewill other wisebedamaged.
The display messages andthecorr espondin gsymbol thatindicat ethat thecoolant levelis
too low must notbeignored. 254
Display
messagesOn-board computer and displays

Disp
laymessa ges Poss
iblecauses/c onseq uences and M Solu
tions ?
Coo
lantLev elLow Sto
pVeh icl eTur n Eng
ine Off The
coolan tistoo hot.
X Pull over andstop thevehicle safelyandswitch offthe engine,
pay ing attent iontoroad andtraffic conditions.
X Make surethattheairsuppl yto the engine radiatorisnot
blocked, e.g.bysnow, slushorice.
X Wait untilthedispla ymessage disappearsbefore restarting the
engine. Otherwise, thereisarisk ofengine damage .
X Pay attent iontothe coolant temperature display.
X Ifthe temperature increasesagain,visit aqual ified speciali st
workshop immediately . The
poly-V-belt mayhave torn.
X Pull over andstop thevehicle safelyandswitch offthe engine,
pay ing attent iontoroad andtraffic conditions.
X Open thehood.
X Check whether thepoly-V-belt istorn.
If the poly-V-belt istorn:
! Donot cont inue driving. Theengine couldotherwise overheat.
X Consult aqual ified speciali stworkshop.
If the poly-V-belt isnot dam aged:
X Wait untilthedispla ymessage disappearsbefore restarting the
engine. Otherwise, thereisarisk ofengine damage .
X Pay attent iontothe coolant temperature display.
X Visit aqual ified speciali stworkshop. G
WARNING Driving
whenyourengine isoverheated cancause somefluidswhich mayhave leaked intothe
engine compartment tocatch fire.Youcould beseriously burned.
Steam fromanoverheated enginecancause serious burnswhich canoccur justbyopening the
engine hood.Stayawayfrom theengine ifyou seeorhear steam coming fromit.
Stop thevehicle inasafe location awayfrom other traffic. Turnoffthe engine, getout ofthe
vehicle anddonot stand nearthevehicle untiltheengine hascooled down.
! Ifthe coolant temperature exceeds248‡(120 †)donot cont inue driving. Theengine will
otherwise bedamage d. Dis
play messages
255On-board computer and displays Z

Disp
laymessa ges Poss
iblecauses/c onseq uences and M Solu
tions ? The
engin efan isdef ective.
X At coolan ttemperatures under248‡(120 †),drive tothe next
qualified specialist workshop.
X Avo idsubjec tingthe engin etoheavy loads, e.g.driving in
mountainous terrain,andstop- and-go traffic. # The
battery isnot being charged.
Possible causesare:
R adefectiv ealternator
R atorn poly-V-belt
R amalfunct ioninthe electron ics
X Pull over andstop thevehicle safelyandswitch offthe engine,
paying attentiontoroad andtraffic conditions.
X Open thehood.
X Check whether thepoly-V-belt istorn .
If the poly-V- beltistorn:
! Donot cont inue driving. Theengine couldotherwise overheat.
X Consult aquali fiedspecialist workshop.
If the poly-V- beltisnot dam aged:
X Visit aquali fiedspecialist workshop. 4
Check
Engine Oil At
Next Refueling The
engine oillevel hasdropped tothe minimum level.
Aw arning tone also soun ds.
X Chec kthe engine oillevel atthe latest whennextrefueling
(Y page 313).
X Ifnecessary, addengine oil(Ypage 314).
X Ifengine oilneeds tobe added moreoften thanusual,have the
engine checkedataqual ified specialist workshop. Inform
ationonapproved engineoilscan beobtained fromanyqual ified specialist workshop
or on the Internet athttp: //www.mbusa.com (USAonly).
! The oillevel istoo low. Avoid longjourneys withtoolittle engine oil.There isarisk of
engine damage.
The displa ymessages andthecorresponding symbolthatindicate thattheoillevel istoo
low must notbeignored. 256
Display
messagesOn-board computer and displays

Disp
laymessa ges Poss
iblecauses/c onseq uences and M Solu
tions 8
Fue
lLev el Low The
fuellev elhas dropped into theres erveran ge.
X Refu elat thene ares tgas statio n. C Ther
eis on lyaver ysmal lamoun toffuel inthef uel tank.
X Refue lat thene ares tgas statio nwitho utfail. 8
Gas
CapLoos e The
fuel systempress ureistoo low. Thefuel filler capisnot clos ed
cor rectlyorthe fuel systemisleakin g.
X Check thatthefuel filler capiscor rectlyclos ed.
If th efuel filler capisnot corr ectly closed:
X Close thefuel filler cap.
If th efuel filler capiscorr ectly closed:
X Visit aqualified specialist workshop. 8
Ultr
aLow- sulfur Dies
elFuel Only Vehic
leswith adiesel engine: thefuel level hasfallen below the
reser verang e.
X Refuel atthe near estgas station .
X Only usecom merc iallyavailable vehicularULTRA -LOW SUL FUR
HIGH WAYDIES EL FUE L(ULS D,15 ppm SULFUR MAXIMUM ). ¸
Repl
aceAir Filter Vehic
leswith adiesel engine: theengineairfilterisdirt yand must
be replac ed.
X Visit aqualified specialist workshop. !
Chec
kFuel Filter Vehic
leswith adiesel engine: thereiswater inthe fuel filter. The
water mustbedrain edoff.
X Visit aqualified specialist workshop. Ø
Chec
k Addi
tive See
Oper
ator'sManu al The
DEFtan kis empt y.
X Have theDEFtank filledas soon asposs ibleataq ualifi ed
spec ialist workshop(Y page 152). Ø
Rem
aining Starts: 16 The
DEFlevel hasfallen toaminimum.
X Have theDEFtank filledimm ediat elyataqualifi edspec ialist
work shop.(Y page 152) Displ
aymes sages
257On-board computer and displays Z

Disp
laymessa ges Poss
iblecauses/c onseq uences and M Solu
tions Lan
eKee ping Ass
ist Ino
perative or Act
ive Lane Kee
pingAss ist Ino
perative Lan
eKee pingAs sis torA ctive Lane Keeping Assi stisdef ectiv e.
X Vis itaqu alifi ed spe cialist wo rksho p. Blin
dSpot Assist Curr
ently Unav
ailableSee Oper
ator'sManu al or Acti
veBlin d Spot
Assist Curr
ently Unav
ailableSee Oper
ator'sManu al Bli
nd Spot Assistor Active Blind Spot Assististemp orarily
inop erative .Possible causesare:
R you have established theelectric alconn ection between the
trailer andyour vehicle.
R the sensors aredirty.
R funct ionisimpaired duetoheavy rainorsnow.
R the radar sensor system isoutside theoperating temperature
range.
R the radar sensor system istemporarily inoperative, e.g.due to
electrom agneticradiation emittedbynearby TVorradio
station sor other sources ofelectrom agneticradiation.
The yellow 9indicator lampsalsolight upinthe exter ior
mirrors.
X When towing atrailer, confirmthedisplay message witha.
If you aredriving without atrailer andthedisplay message does
not disappea r:
X Pull over andstop thevehicle safelyassoon aspossible, paying
atten tiontoroad andtraffic conditions.
X Apply theelectric parking brake.
X Clean thesensors (Ypage 322).
X Restart theengine.
If the system detectsthat thesensors arefully operational, the
display message disappears.
Blind SpotAssist orAct ive Blind SpotAssist isoperational again. Blind
SpotAssist Inoperative
or Active
Blind Spot
Assist Inoperative Blind
SpotAssist orAct ive Blind SpotAssist isdefectiv e.
The yellow 9indicator lampsalsolight upinthe exter ior
mirrors.
X Visit aquali fiedspecialist workshop. Park
Assist Canceled The
driver's doorisopen andthedriver's seatbelthasnotbeen
fasten ed.
X Repeat theparking process withtheseat beltfastened andthe
driver's doorclosed. 260
Display
messagesOn-board computer and displays