warning light MERCEDES-BENZ C CLASS 2019 Workshop Manual

Ifthe indicator/warning lamps inthe instrumentcluster do not light up at lowtemperatures, it isverylikelythatthe discharged battery has fro‐zen. Inthis caseyou may neither jump-startthevehicle norchargethe battery.
The service life of a batterythat has beenthawed may be dramatically shortened. Thestartingcharacteristics may be impaired, espe‐cially at lowtemperatures.
It isrecommendedthatyou haveathawed bat‐terychecked at aqualified specialistworkshop.
AllvehiclesPlug-inhybrid:observethe notes inthe Supple‐ment. Otherwise,you mayfailtorecognize dan‐gers.
NOTEDamagecausedbynumerous orextended attemptstostartthe engine
Numerous orextended attemptstostarttheengine may damagethe catalytic converterduetonon-combusted fuel.
Avoid numerous andextended attemptstostartthe engine.
Observethefollowing points duringstartingassistance and whenchargingthe battery:
ROnly use undamaged jumper cables/charg‐ing cables with a sufficient cross-section andinsulatedterminal clamps.
RNon-insulated parts oftheterminal clampsmust not come into contact withother metalparts whilethe jumper cable/charging cableis connectedtothe battery/jump-startcon‐nection point.
RThe jumper cable/charging cable must notcome into contact withany parts which maymovewhenthe engine isrunning.
RAlways make surethat neitheryou northebattery is electrostaticallycharged.
RKeepawayfromfireand openflames.
RDo not leanoverthe battery.
Observethe additionalfollowing points whenchargingthe battery:
ROnly use batterychargerstested andapprovedfor Mercedes-Benz.
RReadthe batterycharger's operating instruc‐tions beforechargingthe battery.
Observethe additionalfollowing points duringstarting assistance:
RStarting assistance may only be providedusing batteries with a nominalvoltage of12V.
RThevehicles must nottouch.
RGasoline engine:Onlyacceptstarting assis‐tance ifthe engine andexhaust system arecold.
Starting assistance andchargingthe12 Vbattery
Requirements:RThevehicle is secured withthe electric park‐ing brake.
RAutomatic transmission:The transmissionis in position].
RThe ignition and all electrical consumers areswitched off.
RThe hood is open.
Breakdown assistance37 9

RImpaired driving comfort
RSusceptibilitytodamage
\nWARNINGRisk of accident causedbyrepeated drop in tire pressure
Ifthe tire pressure dropsrepeatedly,thewheel,valve or tire may be damaged.
Insufficient tire pressure can causethe tirestoburst.
Inspectthe tirefor signs offoreignobjects.
Check whetherthe wheel orvalve has aleak.
Ifyou are unabletorectifythe damage,contact aqualified specialistworkshop.
You canfind information on tire pressureforthevehicle'sfactory-installed tires onthefollowinglabels:
RTireand Loading Information placard ontheB‑pillar ofyourvehicle (page 399).
RTirepressuretable onthe inside ofthe fuelfillerflap (page 393).
Observethe maximum tire pressure(page 406).
Use a suitable tire pressuregaugetocheckthetire pressure. The outer appearance of a tiredoes not permit anyreliable conclusion aboutthe tire pressure.
Vehicles with a tire pressure monitoring sys‐tem:You can alsocheckthe tire pressure usingthe on-board computer.
Only correct tire pressure whenthe tires arecold. Conditionsfor cold tires:
RThevehicle has been parked withthe tiresout of direct sunlightfor at leastthree hours.
RThevehicle has traveled lessthan 1 mile(1.6 km).
Arise inthe tiretemperature of18°F (10 °C)increasesthe tire pressurebyapprox.10kPa(0.1 bar/1.5 psi).Takethis into account whencheckingthe tire pressure ofwarmtires.
The tire pressure recommendedfor increasedload/speed inthe tire pressuretable can affecttheride comfort.
\nWARNINGRisk of accident from unsuita‐ble accessories onthe tirevalves
Ifyou mount unsuitable accessories ontotirevalves,the tirevalves may beoverloaded andmalfunction, which can cause tire pressureloss.Tirepressure monitoring systemsforretrofitting will causethe tirevalvetoremainopen. This can alsoresult in tire pressureloss.
Only screwstandardvalve caps orvalvecaps specifically approvedbyMercedes-Benzforyourvehicle ontothe tirevalve.
Tirepressure table
The tire pressuretable is onthe inside ofthefuelfillerflap.
The data shown inthe images isexampledata.
Wheels and tires393

Screwthevalve cap ontothevalve.
Furtherrelated subjects:
RNotes on tire pressure (page 392)
RTirepressuretable (page 393)
RTireand Loading Information placard(page 399)
Tirepressure monitoring system
Function ofthe tire pressure monitoring sys‐tem
\nDANGERRisk of accident duetoincor‐rect tire pressure
Every tire, includingthe spare (if provided),should bechecked when cold at least once amonth and inflatedtothe pressurerecom‐mendedbythevehicle manufacturer (seeTireand Loading Information placard ontheB-pillar onthe driver’sside orthe tire pres‐sure label onthe inside ofthe fuelfillerflapofyourvehicle). Ifyourvehicle has tires of adifferent sizethanthe size indicated onthe
Tireand Loading Information placard orthetire pressuretable,you needtodeterminethe proper tire pressureforthose tires.
As an added safetyfeature,yourvehicle hasbeen equipped with a tire pressure monitor‐ing system (TPMS)that illuminates a low tirepressure indicator lamp when one or more ofyour tires are significantly underinflated.Accordingly, ifthe low tire pressure indicatorlamp lights up,you shouldstop andcheckyour tires as soon as possible, and inflatethemtothe proper pressure. Driving on asignificantly underinflated tire causesthe tireto overheat and can leadtotirefailure.Underinflation also increases fuel consump‐tion andreduces tire tread life, and mayaffectthevehicle's handling and braking abil‐ity. Please notethatthe TPMS is not a substi‐tutefor proper tire maintenance, and it isthedriver'sresponsibilitytomaintain correct tirepressure,even if underinflation has notreachedthe leveltotrigger illumination ofthe TPMS low tire pressure indicator lamp.
Yourvehicle has also been equipped with aTPMS malfunction indicatortoindicate whenthe system is not operating properly. TheTPMS malfunction indicator is combined withthe low tire pressure indicator lamp. Whenthe system detects a malfunction,the indica‐tor lamp willflashfor approximatelya minuteandthenremain continuously illuminated.This sequence will continue upon subsequentvehiclestart-ups as long asthe malfunctionexists.
Whenthe malfunction indicator is illumina‐ted,the system may not be abletodetect orsignal low tire pressure as intended. TPMSmalfunctions may occurfor avariety ofrea‐sons, includingthe installation of incompati‐blereplacement or alternate tires or wheelsonthevehiclethat preventthe TPMS fromfunctioning properly.
Alwayscheckthe TPMS malfunctionwarninglamp afterreplacing one or more tires orwheels onyourvehicletoensurethatthereplacement or alternate tires and wheels
Wheels and tires395

\nWARNING‑ Risk offireand injury fromwindshieldwasher concentrate
Windshieldwasher concentrate is highlyflammable. It could ignite if it comes intocontact withhot engine component parts ortheexhaust system.
Make surethat no windshieldwasherconcentrate spills out nexttothefilleropening.
NOTEDamagetotheexterior lightingduetounsuitable windshieldwasherfluid
Unsuitable windshieldwasherfluid may dam‐agethe plastic surface oftheexterior light‐ing.
Only use windshieldwasherfluid whichis also suitablefor use on plastic surfa‐ces, e.g. MB SummerFit or MBWinter‐Fit.
NOTEBlocked spraynozzles causedbymixing windshieldwasherfluids
Do not mix MB SummerFit and MBWin‐terFit withother windshieldwasherflu‐ids.
Do not use distilled or de-ionizedwater asthefilllevel sensor may be triggered erroneously.
Recommended windshieldwasherfluid:
RAbovefreezing point: e.g. MB SummerFit
RBelow freezing point: e.g. MBWinterFit
Forthe correct mixingratio,refertothe informa‐tion onthe antifreeze container.
Mixthewasherfluid withthe windshieldwasherfluid allyearround.
Refrigerant
Notes onrefrigerantsObservethe notes on operatingfluids(page 425).
NOTEDamageduetoincorrectrefriger‐ant
If a non-approvedrefrigerant is used,the cli‐mate control system may be damaged.
Only usetherefrigerant R‑134a
NOTEDamagetothe climate controlsystem duetoincorrectrefrigerant com‐pressor oil
Only userefrigerant compressor oilthathas been approvedbyMercedes-Benz.
Do not mixthe approvedrefrigerantcompressor oil with a differentrefriger‐ant compressor oil.
Workonthe climate control system may be car‐ried out onlybyaqualified specialistworkshop.All applicableregulations, aswell asSAEstand‐ard J639, must be adheredto.
The instruction label onthe climate control sys‐temfortherefrigerant type andtherefrigerantcompressor oil is located onthe inside ofthehood.
430Technical data

Display messagesPossible causes/consequences andPPSolutions
Observethe notes onthe diagnostics connection (page 25).
Visit aqualified specialistworkshop.
S
Inoperative
*At least one main function ofthe Mercedes me connect system or ofthe SOS emergency call system is malfunc‐tioning.
Visit aqualified specialistworkshop.
u
Front Left MalfunctionService Required(Example)
*The correspondingrestraint system isfaulty (page 34).
\nWARNINGRisk of injuryorfatal injury duetoa malfunction intherestraint system
Iftherestraint system is malfunctioning,restraint system components may be triggered unintentionally ormight not be triggered at all intheevent of an accident. This may affectthe EmergencyTensioning Device orairbag,forexample.
Havetherestraint systemchecked andrepaired immediately at aqualified specialistworkshop.
Detection of arestraint system malfunction:
RTheurestraint systemwarning lamp does not light up whenthe ignition is switched on.
RTheurestraint systemwarning lamp lights up continuously orrepeatedly during a journey.
Visit aqualified specialistworkshop immediately.
446Displaymessages andwarning/indicator lamps

Display messagesPossible causes/consequences andPPSolutions
Active Brake Assist Func-tions Currently Limited SeeOperator's Manual
*Vehicles withthe Driving AssistancePackage:Active Brake Assistwith cross-traffic function, EvasiveSteering
Assist or PRE‑SAFE®PLUS aretemporarily unavailable or only partiallyavailable.
Vehicles withoutthe Driving Assistance package:Active Brake Assististemporarily unavailable.
The ambient conditions are outsidethe system limits (page175).
Drive on.As soon asthe ambient conditions are withinthe system limits,the system will becomeavailable again.
Ifthe display message does not disappear,stopthevehicle while paying attentiontoroad and traffic conditionsandrestartthe engine.
u
SRS Malfunction ServiceRequired
*Therestraint system isfaulty (page 34).
\nWARNINGRisk of injuryorfatal injury duetoa malfunction intherestraint system
Iftherestraint system is malfunctioning,restraint system components may be triggered unintentionally ormight not be triggered at all intheevent of an accident. This may affectthe EmergencyTensioning Device orairbag,forexample.
Havetherestraint systemchecked andrepaired immediately at aqualified specialistworkshop.
Detection of arestraint system malfunction:
RTheurestraint systemwarning lamp does not light up whenthe ignition is switched on.
RTheurestraint systemwarning lamp lights up continuously orrepeatedly during a journey.Visit aqualified specialistworkshop immediately.
Displaymessages andwarning/indicator lamps447

Lights
Display messagesPossible causes/consequences andPPSolutions
I
Intell. Light System Inoper-ative
*The Intelligent Light System is defective. The lighting system continuestofunction properly withoutthe functions ofthe Intelligent Light System.
Visit aqualified specialistworkshop.
I
Check Left LowBeam(Example)
*The corresponding light source is defective.
Drive on carefully.
Visit aqualified specialistworkshop immediately.
or
Check whetheryou are permittedtoreplacethe light sourceyourself (page129).
LED light bulbs:the display messageforthe corresponding lamp appearsonly when allthe light-emitting diodesinthe lamp havefailed.
I
Active Headlamps Inopera-tive
*The active headlamps are defective.
Visit aqualified specialistworkshop.
476Displaymessages andwarning/indicator lamps

Display messagesPossible causes/consequences andPPSolutions
I
Switch Off Lights
*You are leavingthevehicle andthe lights arestill switched on.
Turnthe light switchtotheXposition.
I
Malfunction See Opera-tor’s Manual
*Theexterior lighting is defective.
Visit aqualified specialistworkshop.
I
Switch On Headlamps
*You are driving without low-beam headlamps.
Turnthe light switchtotheXorXposition.
I
Automatic Headlamp ModeInoperative
*The light sensor isfaulty.
Consult aqualified specialistworkshop.
*Adaptive Highbeam Assist is malfunctioning.
Display messages andwarning/indicator lamps477

Warning and indicator lamps
Overview ofwarning and indicator lamps
Some systems will performa self-test whentheignition is switched on. Somewarning and indi‐cator lamps may brieflylight up orflash. Thisbehavior is non-critical. Thesewarning and indi‐cator lamps indicate a malfunction only iftheylight up orflash afterthe engine has beenstar‐ted or during a journey.
Instrument Display (standard)
Widescreen Cockpit Instrument Display
Depending onthe display setting,the positionsofthe indicator lamps onthe Instrument Displaymay differ fromtheexample shown.
Warning and indicator lamps:XLow beam (page122)
`Parking lights (page122)
WHigh beam (page124)
>=Turnsignal indicator(page124)
^Rearfog light(page122)
uRestraint system (page 480)

Warning/indicator lampPossible causes/consequences andPPSolutions
Restraint systemwarninglamp\nWARNINGRisk of injuryorfatal injury duetoa malfunction intherestraint system
Iftherestraint system is malfunctioning,restraint system components may be triggered unintentionally or might notbe triggered at all intheevent of an accident. This may affectthe EmergencyTensioning Device or airbag,forexam‐ple.
Havetherestraint systemchecked andrepaired immediately at aqualified specialistworkshop.
Drive on carefully.
Observethe messages onthe multifunction display.
Visit aqualified specialistworkshop immediately.
Seat belts
Warning/indicator lampPossible causes/consequences andPPSolutions
v
Seat beltwarning lamplights up
Thered seat beltwarning lamp will light upfor six seconds oncethe engine hasstarted.
In addition, awarningtone may sound.
The seat beltwarning lampremindsthe driver and front passengertofastentheir seat belts.
Fastenyour seat belt (page 38).
Ifyou haveplaced objects onthe front passenger seat,the seat beltwarning lamp mayremain lit.
Display messages andwarning/indicator lamps485