Engine
Display messagesPossible causes/consequences andMSolutions
+
CheckCoolantLevelSee Operator's Man‐ual
The coolant level is too low.
!Avoid making long journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
XAdd coolant, observing the warning notes before doing so
(Ypage 231).
XIf coolant needs to be added more often than usual, have the engine coolant system checked at a qualified specialist workshop.
?The fan motor is faulty.
XAt coolant temperatures below 248 ‡(120 †), drive to the nearest
qualified specialist workshop.
XAvoid heavy loads on the engine as you do so, e.g. driving in moun-
tainous terrain and stop-and-go traffic.
?
Coolant Too HotStop Vehicle TurnEngine Off
The coolant is too hot.
A warning tone also sounds.
GWARNING
Do not drive when your engine is overheated. This can cause some
fluids which may have leaked into the engine compartment to catch
fire.
Steam from the overheated engine can also cause serious burns which
can occur just by opening the hood.
There is a risk of injury.
XPull over and stop the vehicle safely and switch off the engine, pay- ing attention to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 119).
XWait until the engine has cooled down.
XMake sure that the air supply to the engine radiator is not blocked,e.g. by snow, slush or ice.
XDo not start the engine again until the display message goes out and
the coolant temperature is below 248 ‡ (120 †). Otherwise, the
engine could be damaged.
XPay attention to the coolant temperature display.
XIf the temperature increases again, visit a qualified specialist work-
shop immediately.
Under normal operating conditions and with the specified coolant
level, the coolant temperature may rise to 248 ‡ (120 †).
178Display messages
On-board computer and displays
Display messagesPossible causes/consequences andMSolutions
4
Engine Oil ReduceOil Level
You haveadded to omuc hengin eoil. The engin eor catalytic converter
may be damaged.
XSiphon off excess engin eoil until it is at th especified level. Observ e
th elegal requirements .
4
Engine Oil LevelCannot Be Measured
The measuringsystem is faulty.
XVisit aqualified specialist workshop .
8
FuelLevel Low
The fuel level has dropped int oth ereserv erange.
XRefue lat th eneares tgas station .
CThere is only aver ysmall amount of fuel in th efuel tank.
XRefue lat th eneares tgas station without fail .
8
Gas Cap Loose
The fuel filler cap is notclosed correctl yor th efuel system is leaking .
XCheckthat th efuel filler cap is correctl yclosed .
If th efuel filler cap is not correctl yclosed :
XCloseth efuel filler cap .
If th efuel filler cap is correctl yclosed :
XVisitaqualified specialist workshop .
Driving systems
Display messagesPossible causes/consequences and MSolutions
À
ATTENTION ASSIST:Take a Break!
Based on certain criteria, ATTENTION ASSIST has detecte dfatigue or
a lack of concentration on th epart of th edriver . Awarning tone also
sounds.
XIf necessary, tak e abreak.
During lon gjourneys, tak eregular breaks in goo dtime so you get
enough rest.
À
ATTENTION ASSISTInoperative
ATTENTION ASSIST is inoperative.
XVisit aqualified specialist workshop .
¨
Malfunction
There isamalfunction in th echassis. The vehicle's handlin gcharac -
teristics may be affected.
XVisit aqualified specialist workshop .
180Display messages
On-board computer and displays
Display messagesPossible causes/consequences andMSolutions
LaneKeepin gAssistCurrently Unavaila‐ble See Operator' sManual
LaneKeepin gAssis tis deactivated and temporarily inoperative.
Possibl ecauses are:
Rth ewindshield in th ecamera' sfield of vision is dirty.
Rvisibilit yis impaire ddue to heav yrain ,snow or fog .
Rthere havebeen no lan emarking sfor an extended period.
Rth elan emarking sare worn, dark or covered, e.g. by dir tor snow.
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
Lan eKeepin gAssis tis operational again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 119).
XClean th ewindshield.
Lan eKeepin gAssistInoperativeLaneKeepin gAssis tis faulty.
XVisit aqualified specialist workshop .
Blind SpotAssistCurrently Unavaila‐ble See Operator' sManual
Blind Spot Assistis temporarily inoperative.
Possibl ecauses are:
Rth eradar sensor system is outside th eoperating temperature
range.
Rth eradar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation .
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
Blind Spot Assis tis operational again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 119).
XRestart th eengine.
Blind Spo tAssistInoperativeBlind Spot Assis tis defective.
XVisit aqualified specialist workshop .
ë
Off
The HOLD function is deactivated. The vehicl eis skidding.
A warning tone also sounds.
XReactivat eth eHOLD function later (Ypage 136).
The HOLD function is deactivated. Whe nth ebrak epedal is firmly
depressed, an activation condition is no tfulfilled .
A warning tone also sounds.
XChec kth eactivation condition sfor th eHOLD function
(Ypage 136).
Display messages18 1
On-board computer and displays
Z
Display messagesPossible causes/consequences andMSolutions
DISTRONIC PLUSOffDISTRONI CPLU Shas been deactivated (Ypage 128).
If it was no tdeactivated by th edriver , awarning tone also sounds.
DISTRONIC PLU SNowAvailableDISTRONI CPLU Sis operational again after having been temporarily
unavailable .You can no wreactivat eDISTRONI CPLU S (Ypage 128).
DISTRONIC PLU SCur ‐rently UnavailableSee Operator' sMan ‐ual
DISTRONI CPLU Sis temporarily inoperative.
Possibl ecauses are:
Rth eradar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation .
Rthesystem is outside th eoperating temperature range.
Rth eon-boar dvoltag eis to olow.
A warning tone also sounds.
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
DISTRONI CPLU Sis operational again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 119).
XRestart th eengine.
DISTRONICPLU SInop‐erativ eDISTRONI CPLU Sis defective.
A warning tone also sounds.
XVisit aqualified specialist workshop .
DISTRONIC PLUSSus ‐pendedYou hav edepressed th eaccelerato rpedal .DISTRONI CPLU Sis no
longer controllin gth espeed of th evehicle.
XRemove your foo tfrom th eaccelerato rpedal .
DISTRONIC PLU S- - -mphAn activation condition for DISTRONI CPLU Sis no tfulfilled .
XCheckth eactivation condition sfor DISTRONI CPLU S (Ypage 128).
DISTRONIC PLU SandSPEEDTRONIC Inoper ‐ative
DISTRONICPLU Sand SPEEDTRONI Care faulty. Awarning tone also
sounds.
XVisit aqualified specialist workshop .
CruiseControlInop‐erativeCruisecontrol is malfunctioning .
A warning tone also sounds.
XVisit aqualified specialist workshop .
182Display messages
On-board computer and displays
Display messagesPossible causes/consequences andMSolutions
NThe tailgateis open .
GWARNIN G
Whe nth eengin eis running, exhaust gase scan ente rth evehicl einte-
rio rif th etailgat eis open .
There is aris kof poisoning .
XCloseth etailgate.
MThe hoo dis open . Awarning tone also sounds.
GWARNIN G
The open hoo dmay bloc kyour vie wwhen th evehicl eis in motion .
There is aris kof an accident.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 119).
XCloseth ehood.
CAt least on edoor is open . Awarning tone also sounds.
XClos eall th edoors.
Rea rSpoile rCon ‐trolSystem Inoper ‐ative
The rear spoiler canno tbe full yretracte dand may extend again .
If th eretraction of th erear spoiler is blocked, e.g. by ice :
XMakesur ethat th ecaus eof th ebloc kis eliminated.
XSwitc hoff th eengin eand loc kth evehicle.
XStart th evehicl eafter waiting afew minutes.
The rear spoiler return sto th eoriginal position .
If this problem persists or th ecaus ecanno tbe identified:
XVisit aqualified specialist workshop .
RearSpoile rInoper‐ative Limit 125 mphThe rear spoiler canno tbe full yextended and extend sas far as pos -
sible.
The speed of th evehicl eis limite dto 12 5mph (20 0km/h ).
If the extension/retraction of the rear spoiler is blocked, e.g. by ice:
XMake sure that the cause of the block is eliminated.
XSwitch off the engine and lock the vehicle.
XStart the vehicle after waiting a few minutes.
The rear spoiler returns to the original position.
If this problem persists or the cause cannot be identified:
XVisit a qualified specialist workshop.
Display messages187
On-board computer and displays
Z
Display messagesPossible causes/consequences andMSolutions
Â
Key Not Detected(whitedisplay message )
The SmartKey is currentl yundetected.
XChange th elocation of th eSmartKey in th evehicle.
If th eSmartKey still canno tbe detected:
XInser tth eSmartKey int oth eignition loc kand tur nit to th edesire d
position .
Â
Key Not Detected(reddisplay message )
The SmartKey is no tin th evehicle.
A warning tone also sounds.
If th eengin eis switched off ,you can no longer loc kth evehicl ecen-
trally or start th eengine.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 119).
XLocate th eSmartKey.
XPress aon thesteering whee lto confirm th edisplay message .
Becausethere is interferenc efrom astron gsource of radi owaves, th e
SmartKey is no tdetecte dwhils tth eengin eis running.
A warning tone also sounds.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 119).
XInsertth eSmartKey int oth eignition loc kand bring int oke ymode.
Â
Insert Key
The SmartKey is continually undetected.
The SmartKey detection function has atemporar ymalfunction or is
faulty. Awarning tone also sounds.
XInser tth eSmartKey int oth eignition loc kand tur nit to th edesire d
position .
XVisitaqualified specialist workshop .
Warning and indicat orlamps in the instrume nt cluster
General notes
Some systems carry out aself-diagnosis when th eignition is switched on .Therefore ,som eindicator
and warning lamp smay ligh tup or flas htemporarily. This behavio ris non-critical .These indicator
and warning lamp sonly indicat e amalfunction if they ligh tup or flas hafter starting th eengin eor
whils tdriving.
Warning and indicator lamps in the instrument cluster189
On-board computer and displays
Z
Safety systems
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
$JN$ (USA only), J(Canada only): the red brake system warning lamp is lit
while the engine is running. A warning tone also sounds.
GWARNING
The brake boosting effect is malfunctioning and the braking characteristics may be
affected.
There is a risk of an accident.
XPull over and stop the vehicle safely as soon as possible, paying attention to road
and traffic conditions. Do not continue driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 119).
XVisit a qualified specialist workshop immediately.
XObserve the additional display messages in the multifunction display.
$JN $ (USA only), J(Canada only): the red brake system warning lamp is lit
while the engine is running. A warning tone also sounds.
There is not enough brake fluid in the brake fluid reservoir.
GWARNING
The braking effect may be impaired.
There is a risk of an accident.
XPull over and stop the vehicle safely as soon as possible, paying attention to road
and traffic conditions. Do not continue driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 119).
XDo not add brake fluid. Adding more will not correct the malfunction.
XConsult a qualified specialist workshop.
XObserve the additional display messages in the multifunction display.
$N USA only: the red brake system warning lamp is lit while the engine is running.
The multifunction display also shows a display message with the #symbol.
The brake pads/linings have reached their wear limit.
XVisit a qualified specialist workshop.
Warning and indicator lamps in the instrument cluster191
On-board computer and displays
Z
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
XMake sure that the air supply to the engine radiator is not blocked, e.g. by snow,
slush or ice.
XAt coolant temperatures below 248 ‡ (120 †), drive to the nearest qualified
specialist workshop.
XAvoid subjecting the engine to heavy loads, e.g. driving in mountainous terrain,
and stop-and-go traffic.
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. A warning
tone also 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 careful attention to the traffic situation. You may have to brake or take
evasive action.
For further information about the distance warning function of COLLISION PRE-
VENTION ASSIST PLUS, see (
Ypage 53).
Warning and indicator lamps in the instrument cluster197
On-board computer and displays
Z