steering MERCEDES-BENZ C CLASS 2019 Repair Manual

Tirepressure
Notes on tire pressure
\nWARNINGRisk of accident duetoinsuf‐ficient orexcessive tire pressure
Underinflated oroverinflated tires posethefollowingrisks:
RThe tires may burst, especially astheload andvehicle speed increase.
RThe tires maywearexcessively and/orunevenly,which maygreatlyimpair tiretraction.
RThe drivingcharacteristics, aswell assteering and braking, may be greatlyimpaired.
Comply withtherecommended tirepressure andcheckthe tire pressure ofall tires includingthe spare wheelregu‐larly:
Rat least once a month
Rwhenthe loadchanges
Rbefore embarking on a longer journey
Rif operating conditionschange, e.g. off-road driving
Adjustthe tire pressure as necessary.
Driving withtire pressurethat istoo high ortoolow can:
RShortenthe service life ofthe tires.
RCause increased tire damage.
RAdversely affect drivingcharacteristics andthus driving safety,e.g. dueto hydroplaning.
\nWARNINGRisk of an accident duetoinsufficient tire pressure
Tires with pressurethat istoo low canover‐heat and burstas aresult.
In addition,theyalso suffer fromexcessiveand/or irregularwear, which can significantlyimpairthe braking properties andthe han‐dlingcharacteristics.
Avoidexcessively low tire pressures inallthe tires, includingthe spare wheel.
Tirepressure which istoo low can cause:
RTiredefects as aresult ofoverheating
RImpaired handlingcharacteristics
RIrregularwear
RIncreased fuel consumption
\nWARNINGRisk of accident fromexces‐sive tire pressure
Tires withexcessively high pressure canburstbecausetheyare damaged more easilybyhighwayfill, pot holesetc.
In addition,theyalso suffer from irregularwear, which can significantly impairthe brak‐ing properties andthe handlingcharacteris‐tics.
Avoidexcessively high tire pressures inallthe tires, includingthe spare wheel.
Excessively high tire pressure canresult in:
RIncreased braking distance
RImpaired handlingcharacteristics
RIrregularwear
392Wheels and tires

RTire Pressure Monitor Active:theteach-inprocess ofthe system is notyet complete.The tire pressures are already being moni‐tored.
Comparethe tire pressure withtherecom‐mended tire pressureforthe current operat‐ing condition (page393). Observethenotes on tiretemperature (page 392).
Thevalues displayed inthe multifunction dis‐play may deviate fromthose ofthe tire pres‐suregauge astheyrefertosea level.Athighaltitudes,the tire pressurevalue indicatedbya pressuregauge are higherthanthoseshownbythe on-board computer. Inthiscase, do notreducethe tire pressure.
Make suretoobservethefollowing furtherrela‐ted subject:
RNotes on tire pressure (page 392)
Restartingthe tire pressure monitoring sys‐tem
Requirements:RTherecommended tire pressure is correctlysetfortherespective operatingstatus oneach ofthefour wheels (page 392).
Restartthe tire pressure monitoring system inthefollowing situations:
RThe tire pressure haschanged.
RThe wheels or tires havebeenchanged ornewly installed.
On-board computer:
ServiceTires
Swipe downwards onTouch Control ontheleft-hand side ofthesteering wheel.TheUse Current Pressures as New Refer-ence Values?message is shown inthe multi‐function display.
Tobeginrestart, pressTouch Control ontheleft-hand side ofthesteering wheel.TheTire Press. Monitor Restartedmessage isshown inthe multifunction display.
Currentwarning messages are deleted andtheyellowwwarning lamp goes out.
Afteryou havebeen drivingfor afewminutes,the systemcheckswhetherthe cur‐rent tire pressures are withinthe specifiedrange. The current tire pressures arethenaccepted asreferencevalues and monitored.
Make suretoobservethefollowing furtherrela‐ted subject:
RNotes on tire pressure (page 392)
Radio equipment approval ofthe tire pres‐sure monitoring system
Radio equipment approval numbers
CountryRadio type approval number
Canada IC: 2546A-GG4T
IC: 2546A-DG6W2D4
IC: 2546A-MC34MA4
USAFCC ID: MRXGG4T
FCC ID: MRXDG6W2D4
FCC ID: MRXMC34MA4
Wheels and tires397

Further information onthe declaration of con‐formityfor wirelessvehicle components(page 25).
Tirepressure losswarning system
Function ofthe tire pressure losswarningsystemThe tire pressure losswarning systemwarnsthedriverbymeans of display messages whenthereis a severetire pressureloss.
After achange in tire pressure, a wheelrotationor a tirechange, or ifyou havere-installedwheels or tires,the tire pressure losswarningsystem hastoberestarted (page 398).
The tire pressure losswarning system does notreplacethe needtoregularlycheckthe tire pres‐sure.
System limitations
The system may be impaired or may not functionparticularlyinthefollowing situations:
RIncorrectly set tire pressure
RSudden pressure loss caused,forexample,byaforeign object penetratingthe tire
RSteady pressure loss in several tires
The system has arestricted or delayed functionparticularly inthefollowing situations:
RPoor ground conditions, e.g. snow or gravel
RDriving withsnowchains
RWhen adopting averysporty drivingstylewith high cornering speeds or sudden accel‐eration
RDriving with a high load
Be suretoalso observethefollowing furtherrelated subjects:
RNotes on tire pressure (page 392)
RDisplay messages aboutthe tires(page 466)
Restartingthe tire pressure losswarningsystem
Requirements:RTherecommended tire pressure is correctlysetfortherespective operatingstatus oneach ofthefour wheels (page 392).
Restartthe tire pressure losswarning system inthefollowing situations:
RThe tire pressure haschanged.
RThe wheels or tires havebeenchanged ornewly installed.
On-board computer:
ServiceTires
Swipe downwards ontheTouch Control onthe left-hand side ofthesteering wheel.TheTire Pressure Control SystemActiveRestart: Press Touch Controlmessageis shown inthe multifunction display.
Restartthe tire pressure losswarning system inthefollowing situations:
RThe tire pressure haschanged.
RThe wheels or tires havebeenchanged ornewly installed.
Tobegintherestart, presstheTouch Controlonthe left-hand side ofthesteering wheel.TheTire Pressure Now OK?message isshown inthe multifunction display.
398Wheels and tires

SelectYes.
Toconfirmtherestart, presstheTouch Con‐trol onthe left-hand side ofthesteeringwheel.TheRun Flat Indicator Restartedmessage isshown inthe multifunction display.
Afteryou havedrivenfor afew minutes,thetire pressurelosswarning system monitorsthe set tire pressures of allthe tires.
Be suretoalso observethefollowing furtherrelated subjects:
RNotes on tire pressure (page 392)
Loadingthevehicle
Notes onTireand Loading Information plac‐ard
\nWARNINGRisk of accident fromoverloa‐ded tires
Overloaded tires mayoverheat and burstas aconsequence. Overloaded tires can alsoimpairthesteering and handlingcharacteris‐tics and leadtobrakefailure.
Observethe load-bearing capacity ofthe tires.
The load-bearing capacity must be atleast halfthe gross axleweightrating ofthevehicle.
Neveroverloadthe tiresby exceedingthe maximum load.
TheTireand Loading Information placard is onthe B-pillar onthe driver's side ofthevehicle.
1Tireand Loading Information placard
The data shown inthe illustration isexampledata.
TheTireand Loading Information placard shows:
RMaximum number of seats2accordingtothe maximum number of people permittedtotravel inthevehicle.
RMaximum permissible load3comprisesthegrossweight of allvehicle occupants, loadand luggage.
Wheels and tires399

Display messagesPossible causes/consequences andPPSolutions
\nWARNINGRisk of injuryorfatal injury duetoa disabled front passenger airbag
Ifthe front passenger airbag is disabled,the front passenger airbag will not be deployed intheevent of an acci‐dent and cannotperformits intended protective function.
A person inthe front passenger seat couldthen,forexample, come into contact with thevehicle's interior,especially ifthe person is sittingtoo closetothe cockpit.
Make sure, bothbefore and duringthe journey,thatthestatus ofthe front passenger airbag is correct.
Pullover andstopthevehicle safely as soon as possible, paying attentiontoroad and traffic conditions.
Checkthestatus ofthe automatic front passenger airbag shutoff (page44).
If necessary,consult aqualified specialistworkshop immediately.
Active Brake Assist Func-tions Limited See Opera-tor's Manual
*Vehicles with Driving AssistancePackage:Active Brake Assistwith cross-traffic function, EvasiveSteering
Assist or PRE‑SAFE®PLUS is malfunctioning.
Vehicles without Driving AssistancePackage:Active Brake Assistis malfunctioning.
Visit aqualified specialistworkshop.
PRE-SAFE Inoperative SeeOperator's Manual
*PRE‑SAFE®functions are malfunctioning.
Visit aqualified specialistworkshop.
Mercedes me connectServices Limited See Oper-ator's Manual
*Service limited.
Atleast one ofthe main functions ofthe Mercedes me connect system is malfunctioning.
Display messages andwarning/indicator lamps445

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

Display messagesPossible causes/consequences andPPSolutions
Blind Spot Assist CurrentlyUnavailable See Operator'sManual
*Blind Spot Assist istemporarily unavailable.
The system limits havebeenreached (page219).
Drive on.Oncethe cause ofthe problem is no longer present,the system will beavailable again.
or
Ifthe display message does not disappear,stopthevehicle while paying attentiontoroad and traffic conditionsandrestartthe engine.
If necessary,cleantherear bumper. Ifthe bumper isextremelydirty,the sensors inthe bumper may be mal‐functioning.
Active Steering Assist Inop-erative
*ActiveSteering Assist is malfunctioning.Active Distance AssistDISTRONICremainsavailable.
Visit aqualified specialistworkshop.

Display messagesPossible causes/consequences andPPSolutions
Blind Spot Assist Inopera-tive
Visit aqualified specialistworkshop.
Active Parking Assist andPARKTRONIC InoperativeSee Operator's Manual
*ActiveParking Assist andParking AssistPARKTRONIC are malfunctioning.
Stopthevehicle, paying attentiontoroad and traffic conditions, andrestartthe engine.
Ifthe display message continuestobe displayed, consult aqualified specialistworkshop.
Active Blind Spot AssistCurrently Unavailable SeeOperator's Manual
*Active Blind Spot Assististemporarily unavailable.
The system limits havebeenreached (page219).
Drive on.Oncethe cause ofthe problem is no longer present,the system will beavailable again.
Ifthe display message does not disappear,stopthevehicle while paying attentiontoroad and traffic conditionsandrestartthe engine.
Active Steering Assist Cur-rently Unavailable SeeOperator's Manual
*ActiveSteering Assist istemporarily unavailable.
The ambient conditions are outsidethe system limits (page189).
Drive on.As soon asthe ambient conditions are withinthe system limits,the system will becomeavailable again.
If necessary,cleanthe windshield inthe camera'sfield of vision.
Checkthe tire pressure if necessary.
450Display messages andwarning/indicator lamps

Display messagesPossible causes/consequences andPPSolutions
Active Lane Keeping AssistInoperative
Consult aqualified specialistworkshop.
Malfunction Drive at Max.50 mph
*AIRMATIC is functioning onlytoa limitedextent. Thevehicle's handlingcharacteristics may be affected.
NOTEThe tires ofthe front axle orthe frontfenderscould be damagedbylargesteering movements
Avoid largesteering movements while driving and listenfor scraping sounds.
Ifyou hear scraping sounds, pullover andstopthevehicle safely, paying attentiontoroad and traffic con‐ditions, and set a highervehicle level if possible.
Drive in a manner appropriateforthe current level, but do notexceed 50mph (80 km/h).
Visit aqualified specialistworkshop.DYNAMICBODYCONTROL is malfunctioning. Thevehicle's handlingcharacteristics may be affected.
Do not drive at speeds greaterthan 50mph (80 km/h).
Visit aqualified specialistworkshop.
Blind Spot Assist Not Avail-able When Towing a TrailerSee Operator's Manual
*Whenyou establishthe electrical connectiontothe trailer, Blind Spot Assist is unavailable.
Pressthe left-handTouch Control and acknowledgethe display message.

Display messagesPossible causes/consequences andPPSolutions
Stop Vehicle Vehicle TooLow
Pullover andstopthevehicle, paying attentiontoroad and traffic conditions.Thevehicle israisedtothe selectedvehicle level.
Wait untilthe display message disappears before pullingaway.
Ifthe display message does not disappear and awarningtone also sounds, AIRMATIC is malfunctioning:
Do not drivefasterthan 50mph (80 km/h) and consult aqualified specialistworkshop immediately.
NOTEThe tires ofthe front axle orthe frontfenderscould be damagedbylargesteering movements
Avoid largesteering movements while driving and listenfor scraping sounds.
Ifyou hear scraping sounds, pullover andstopthevehicle safely, paying attentiontoroad and traffic con‐ditions, and set a highervehicle level if possible.
Set a highervehicle level (page198).Depending onthe malfunction,thevehicle israised.
¢
Lowering
*Thevehicle level may be loweredforthefollowingreasons:
Ryou haveselected a different drive program.
Ryou haveexceeded a critical speed.
Ryou havechangedthevehicle levelbypressing a button.
454Display messages andwarning/indicator lamps