Engine
Display messagesPossible causes/consequences andMSolutions
#An additional warning tone sounds. The battery is not being charged.
Possible causes:
Rfaulty alternator
Rtorn poly-V-belt
Ra malfunction in the electronics
XStop the vehicle immediately, paying attention to road and traffic
conditions, and switch off the engine.
!Do not continue driving. The engine could otherwise overheat.
XSecure the vehicle to prevent it from rolling away (Ypage 135).
XConsult a qualified specialist workshop.
?
Coolant Too Hot:Stop Vehicle TurnEngine Off
An additional warning tone sounds. The coolant is too hot.
GWARNING
Never drive with an overheated engine. Driving when the engine is
overheated can cause fluids which may have leaked into the engine
compartment to catch fire.
In addition, steam from an overheated engine can cause serious
burns, which can occur just by opening the hood.
There is a risk of injury.
XStop the vehicle immediately, paying attention to road and traffic
conditions, and switch off the engine.
XSecure the vehicle to prevent it from rolling away (Ypage 135).
XWait until the engine has cooled down.
XMake sure that the air supply to the radiator is not obstructed, by
frozen slush for example.
XDo not start the engine again until the display message goes out and
the coolant temperature is below the maximum value specified. The
engine could otherwise be damaged.
XMonitor the ?coolant temperature gauge in the instrument
cluster.
XIf the temperature increases again, visit a qualified specialist work-
shop immediately.
Under normal operating conditions and with the specified coolant
level, the ?gauge may rise to 248 ‡ (120 †).
214Display messages (vehicles with steering wheel buttons)
On-board computer and displays
Display messagesPossible causes/consequences andMSolutions
Collision Preven‐tionAssist Cur ‐rentlyUnavail.SeeOper. Manual
COLLISION PREVENTION ASSIST PLU Sis temporarily inoperative.
Possibl ecauses:
RThe sensor sin th efron tbumper are dirty.
RThe function is impaire ddue to heav yrain or snow.
RThe radar sensor system is temporarily inoperative, e.g. due to
electromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation .
RThe system is outside th eoperating temperature range.
RThe on-boar dvoltag eis to olow.
Once th ecauses listed abov eno longer apply, th edisplay message
goe sout and COLLISION PREVENTION ASSIST is operational again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicle, payin gattention to roa dand traffic
conditions.
XSecur eth evehicl eto preven tit from rollin gaway (Ypage 135).
XSwitchoff th eengine.
XClean th esensor sin th efron tbumper (Ypage 268).
XRestart th eengine.
Lan eKeepin gAssistInoperativeLaneKeepin gAssis tis faulty.
XVisit aqualified specialist workshop .
LaneKeepin gAssistCurrently Unavail.See Oper. Manual
LaneKeepin gAssis tis deactivated and temporarily inoperative. Pos -
sibl ecauses:
RThe windshield is dirty in th ecamera' sfield of vision .
RVisibilityis impaire ddue to heav yrain ,snow or fog .
RThere are no lan emarking sfor an extended period.
RThe lan emarking sare wor naway, dark or covered, e.g. by dir tor
snow.
Once th ecauses listed abov eno longer apply, th edisplay message
goe sout and Lan eKeepin gAssis tis operational again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicle, payin gattention to roa dand traffic
conditions.
XSecur eth evehicl eto preven tit from rollin gaway (Ypage 135).
XClean th ewindshield.
Cruise Contro lLDC_Spd_DsrspeedUnit
Acondition for activating cruise control has no tbeen met .
You hav etried to store aspeed belo w20 mph (30 km/ h)for example.
XIf conditions permit, drive faster than 20 mph (30 km/h) and store
the speed.
XCheck the activation conditions for cruise control (Ypage 145).
Display messages (vehicles with steering wheel buttons)217
On-board computer and displays
Z
Tires
Display messagesPossible causes/consequences andMSolutions
AdjustTirePressureThe tire pressure is too low in at least one of the tires, or the tire
pressure difference between the wheels is too great.
XCheck the tire pressure at the next opportunity (Ypage 286).
XIf necessary, correct the tire pressure.
XRestart the tire pressure monitor (Ypage 289).
Check TiresAn additional warning tone sounds.
The tire pressure in one or more tires has dropped significantly. The
display shows the wheel position.
GWARNING
Underinflated tires pose the following risks:
RThe tires may burst, especially as the load and vehicle speed
increase.
RThe tires may wear excessively and/or unevenly, which may greatly
impair tire traction.
RThe handling as well as steering and braking characteristics may be
severely affected.
There is a risk of an accident.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions while doing so.
XSecure the vehicle to prevent it from rolling away (Ypage 135).
XCheck the tires and, if necessary, change the wheel (Ypage 298).
XCheck the tire pressure (Ypage 286).
XIf necessary, correct the tire pressure.
Warning Tire Mal‐functionThe tire pressure in one or more tires has dropped suddenly. The dis-
play shows the wheel position.
GWARNING
Driving with a flat tire poses a risk of the following hazards:
RA flat tire affects the ability to steer or brake the vehicle.
RYou could then lose control of the vehicle.
RContinued driving with a flat tire will cause excessive heat build-up
and possibly a fire.
There is a risk of an accident.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions while doing so.
XSecure the vehicle to prevent it from rolling away (Ypage 135).
XCheck the tires and, if necessary, change the wheel (Ypage 298).
Tire Pressure Moni‐tor CurrentlyUnavailable
Due to a source of radio interference, no signals can be received from
the wheel sensors. The tire pressure monitor is temporarily malfunc-
tioning.
The tire pressure monitor restarts automatically as soon as the prob-
lem has been solved.
Displa y messages (vehicles withsteering whee lbu ttons)219
On-board computer and displays
Z
Display messagesPossible causes/consequences andMSolutions
Wheel Sensor(s)MissingThere is no signal from th etire pressur esensor of on eor several
wheels. The pressur eof th eaffecte dtire is no tshown in th edisplay.
XHav eth efault ytire pressur esensor replace dat aqualified special -
ist workshop .
TirePressure Moni‐tor Inoperative NoWheel Sensor s
The wheels installed do no thav esuitable tire pressur esensors. The
tire pressur emonitor is deactivated.
XInstall wheels wit hsuitable tire pressur esensors.
The tire pressur emonitor is activated automatically after drivin gfor
a few minutes.
Tir ePress.Monito rInoperativeThe tire pressur emonitor is malfunctioning .
XVisitaqualified specialist workshop .
Vehicle
Display messagesPossible causes/consequences and MSolutions
Shiftto'P'or'N'to Start EngineYou haveattempte dto start th eengin ein transmission position kor
h.
XShift th etransmission to position jori.
Auxiliary Batter yMalfunctionThe auxiliary battery for th etransmission is no longer bein gcharged.
XVisit aqualified specialist workshop .
Apply Brake toShift from'P'You attempte dto shift th etransmission to position h,kori
without depressing th ebrak epedal .
XDepress th ebrak epedal .
Riskof Rolling:TransmissionNotinP
An additional warning tone sounds. The driver's door is open and th e
transmission is in position k,iorh.
XShift th etransmission to position j.
XSecureth evehicl eto preven tit from rollin gaway (Ypage 135).
Servic eRequiredDoNot Shift GearsVisit Dealer
An additional warning tone sounds. You canno tchang eth etransmis -
sion position due to amalfunction .
If transmission position his selected:
XConsult aqualified specialist workshop without shifting transmis -
sion position h.
If transmission position k,iorj is selected:
XNotify aqualified specialist workshop .
OnlyShift to 'P'whe nVehicl eisSta‐tionar y
The vehicl eis still moving .
XPull overand stop th evehicle, payin gattention to roa dand traffic
conditions.
XShift th etransmission to position j.
220Display messages (vehicles withsteering whee lbu ttons)
On-board computer and displays
Engine
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
;NThe yellow Check Engine warning lamp lights up while the engine is running.
There may be a malfunction, for example:
Rin the engine management
Rin the transmission management
Rin the fuel injection system
Rin the exhaust system
Rin the ignition system (for vehicles with a gasoline engine)
Rin the fuel system
The emission limit values may be exceeded and the engine may be running in
emergency mode.
XHave the vehicle checked as soon as possible at a qualified specialist workshop.
æN The yellow reserve fuel warning lamp is on while the engine is running.
The fuel level has dropped to the reserve range.
XRefuel at the nearest gas station.
?N The red coolant warning lamp comes on while the engine is running.
On vehicles without steering wheel buttons, the coolant temperature gage is at the
start of the bar display (
Ypage 175).
On vehicles with steering wheel buttons, the coolant temperature gage is at the
start of the scale in the instrument cluster (
Ypage 39).
The temperature sensor for the coolant temperature gage is faulty.
The coolant temperature is no longer being monitored. There is a risk of engine
damage if the coolant temperature is too high.
XStop the vehicle immediately, paying attention to road and traffic conditions,
and switch off the engine. Do not continue driving under any circumstances.
XSecure the vehicle to prevent it from rolling away (Ypage 135).
XConsult a qualified specialist workshop.
Indicator and warning lamps in the instrument cluster227
On-board computer and displays
Z
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
?NThe red coolant warning lamp comes on while the engine is running.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may be blocked or
the electric engine radiator fan may be malfunctioning.
The coolant is too hot and the engine is no longer being cooled sufficiently.
XObserve the display messages.
XStop the vehicle immediately, paying attention to road and traffic conditions,
and switch off the engine.
XSecure the vehicle to prevent it from rolling away (Ypage 135).
XExit the vehicle and keep a safe distance from the vehicle until the engine has
cooled down.
XCheck the coolant level and add coolant, observing the warning notes
(Ypage 255).
XIf you have to add coolant more frequently, have the engine cooling system
checked.
XMake sure that the air supply to the radiator is not obstructed, by frozen slush
for example.
XCheck the coolant temperature:
Rusing the display in the on-board computer on vehicles without steering wheel
buttons (Ypage 175)
Rusing the analog display in the instrument cluster on vehicles with steering
wheel buttons (Ypage 39)
XDo not start the engine again until the coolant temperature is below the maxi-
mum value specified below. The engine could otherwise be damaged.
XDrive to the nearest qualified specialist workshop.
Avoid heavy loads on the engine, e.g. driving in mountainous terrain, and stop-
start traffic.
Under normal operating conditions and with the specified coolant level, the cool-
ant temperature gage may rise to 248 ‡ (120 †).
?N The red coolant warning lamp comes on while the engine is running. An addi-
tional warning tone sounds.
The coolant temperature has exceeded the maximum value specified below. The
airflow to the engine radiator may be blocked or the coolant level may be too low.
GWARNING
The engine is not being cooled adequately and could become damaged.
Never drive with an overheated engine. Otherwise, fluids which may have leaked
into the engine compartment could catch fire.
In addition, steam from an overheated engine can cause serious burns, which can
occur just by opening the hood.
There is a risk of injury.
XObserve the display messages.
XStop the vehicle immediately, paying attention to road and traffic conditions,
and switch off the engine.
XSecure the vehicle to prevent it from rolling away (Ypage 135).
228Indicator and warning lamps in the instrument cluster
On-board computer and displays
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
XExit the vehicle and keep a safe distance from the vehicle until the engine has
cooled down.
XCheck the coolant level and add coolant, observing the warning notes
(Ypage 255).
XIf you have to add coolant more frequently, have the engine cooling system
checked.
XMake sure that the air supply to the radiator is not obstructed, by frozen slush
for example.
XCheck the coolant temperature:
Rusing the display in the on-board computer on vehicles without steering wheel
buttons (Ypage 175)
Rusing the analog display in the instrument cluster on vehicles with steering
wheel buttons (Ypage 39)
XIf the coolant temperature is below the maximum value specified below, you can
continue driving to the nearest qualified specialist workshop.
Avoid heavy loads on the engine, e.g. driving in mountainous terrain, and stop-
start traffic.
Under normal operating conditions and with the specified coolant level, the cool-
ant temperature gage may rise to 248 ‡ (120 †).
Driving systems
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
·NThe red distance warning lamp lights up while the vehicle is in motion.
The distance to the vehicle in front is too small for the speed selected.
XIncrease the distance.
·N The red distance warning lamp lights up while the vehicle is in motion. An
additional warning tone sounds.
You are approaching a vehicle or a stationary obstacle in your line of travel at too
high a speed.
XBe prepared to brake immediately.
XPay particular attention to the traffic situation. You may have to brake or take
evasive action.
Further information about the distance warning function can be found under
"COLLISION PREVENTION ASSIST" (
Ypage 146).
Indicator and warning lamps in the instrument cluster229
On-board computer and displays
Z
Tires
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
hNThe yellow tire pressure monitor warning lamp (pressure loss/malfunction) is lit.
The tire pressure monitor has detected a loss of pressure in at least one of the tires.
GWARNING
Underinflated tires pose the following risks:
RThe tires may burst, especially as the load and vehicle speed increase.
RThe tires may wear excessively and/or unevenly, which may greatly impair tire traction.
RThe handling as well as steering and braking characteristics may be severely
affected.
There is a risk of an accident.
XStop the vehicle without making any sudden steering or braking maneuvers. Pay
attention to the traffic conditions while doing so.
XSecure the vehicle to prevent it from rolling away (Ypage 135).
XObserve the display messages.
XCheck the tires and, if necessary, change the wheel (Ypage 298).
XCheck the tire pressure.
You can check the tire pressure electronically on vehicles with steering wheel
buttons (
Ypage 286).
XIf necessary, correct the tire pressure.
hN The yellow tire pressure monitor (pressure loss/malfunction) warning lamp
flashes for approximately one minute and then remains lit.
The tire pressure monitor is malfunctioning.
GWARNING
The system may not be able to detect or signal low tire pressure as intended.
There is a risk of an accident.
XObserve the display messages.
XVisit a qualified specialist workshop.
230Indicator and warninglamps in the instrument cluster
On-board computer and displays