ECU MERCEDES-BENZ C CLASS 2018 Workshop Manual

Display messagesPossible causes/consequences andMSolutions
Driver's DoorOpe n&Transmission Notin PRis kof Vehi‐cle Rollin gAwa y
The driver's door is open or no tfully closed and th etransmission is in
position k,iorh.
A warning tone also sounds.
GWARNIN G
The vehicl emay rol laway.
There is aris kof an accident.
XShift th etransmission to position j.
XSecureth evehicl eagainst rollin gaway (Ypage 161).
XCloseth edriver's door completely.
Onl yShift to 'P'whe nVehicl eisSta‐tionar y
The vehicl eis moving .
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XShift th etransmission to position j.
ServiceRequiredDoNot Shift GearsVisit Dealer
You canno tchang eth etransmission position due to amalfunction .
A warning tone also sounds.
If transmission position his selected:
XDrive to aqualified specialist workshop without shifting th etrans -
mission from position h.
If transmission position k,iorj is selected:
XSecur eth evehicl eagainst rollin gaway (Ypage 161).
XNotify aqualified specialist workshop or breakdown service.
ReversingNotPossi‐bleServic eRequiredYou canno tshift int otransmission position kdue to amalfunction .
The transmission position sj, iorh continu eto be available.
A warning tone also sounds.
XVisit aqualified specialist workshop .
Transmission Mal‐function StopAmalfunction has occurred in th emechanical transmission compo -
nents.
A warning tone also sounds. The transmission automatically shift sto
position i.
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XShift th etransmission to position j.
XSecureth evehicl eagainst rollin gaway (Ypage 161).
XNotify aqualified specialist workshop or breakdown service.
Display messages25 5
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
StopVehicl eLeaveEngineRunnin gWaitTransmission Cool‐ing
The transmission has overheated. Pullin gaway can be temporarily
impaire dor no tpossible.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions. Do no tcontinu edrivin g
under any circumstances.
XLeav eth eengin erunning.
XWait until th edisplay message disappear sbefore pullin gaway.
NThe trunk lid is open .
XCloseth etrunk lid.
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 161).
XCloseth ehood.
CAt least on edoor is open . Awarning tone also sounds.
XClos eall th edoors.
_
Rea rLef tBackrestNot Latche dorRea rRight Backrest NotLatche d
Vehiclewit hthrough-loading feature in th erear bench seat :
The backrest in th erear is no tengage don th eleft-han dand/o rright -
han dside .
XPush th ebackrest bac kuntil it engages.
_
Rea rCenter Back‐res tNot Engage d
Vehiclewit hthrough-loading feature in th erear bench seat :
The center rear seat backrest is no tengaged.
XPush th ebackrest bac kuntil it engages.
256Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
Â
Don't Forget YourKey
The SmartKey is notin th eignition lock. You hav eopened th edriver's
door wit hth eengin eswitched off . Awarning tone sounds
This display message is displayed for amaximum of 60 seconds and is
simply areminder.
XTak eth eSmartKey wit hyou when you leav eth evehicle.
Â
Key Not Detected(whit edisplay 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 161).
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 161).
XInsertth eSmartKey int oth eignition loc kand drive in SmartKey
mode.
Â
Remove 'Start 'But ‐ton and 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.
258Warning and indicator lamps in the instrument cluster
On-board computer and displays

Safety
Seat belts
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
üNAfter starting the engine, the red seat belt warning lamp lights up for six sec-
onds.
The seat belt warning lamp reminds the driver and front passenger to fasten their
seat belts.
XFasten your seat belt (Ypage 48).
üN After starting the engine, the red seat belt warning lamp lights up. In addition, a
warning tone sounds for up to six seconds.
The driver's seat belt is not fastened.
XFasten your seat belt (Ypage 48).
The warning tone ceases.
üN The red seat belt warning lamp lights up after the engine starts, as soon as the
driver's or the front-passenger door is closed.
The driver or front passenger has not fastened their seat belt.
XFasten your seat belt (Ypage 48).
The warning lamp goes out.
There are objects on the front-passenger seat.
XRemove the objects from the front-passenger seat and stow them in a secure
place.
The warning lamp goes out.
üN The red seat belt warning lamp flashes and an intermittent audible warning
sounds.
The driver or front passenger has not fastened their seat belt. The vehicle is being
driven faster than 15 mph (25 km/h) or has briefly been driven faster than 15 mph
(25 km/h).
XFasten your seat belt (Ypage 48).
The warning lamp goes out and the intermittent warning tone ceases.
There are objects on the front-passenger seat. The vehicle is being driven faster
than 15 mph (25 km/h) or has briefly been driven faster than 15 mph (25 km/h).
XRemove the objects from the front-passenger seat and stow them in a secure
place.
The warning lamp goes out and the intermittent warning tone ceases.
Warning and indicator lamps in the instrument cluster259
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 161).
XConsult a qualified specialist workshop.
XObserve the additional display messages in the multifunction display.
$JN $ (USA only), J(Canada only): the red brake system warning lamp lights
up 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 161).
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.
260Warning and indicator lamps in the instrument cluster
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 fuel injection system
Rin the exhaust system
Rin the ignition system (for vehicles with gasoline engines)
Rin the fuel system
The emission limit values may be exceeded and the engine may be in emergency
mode.
XVisit a qualified specialist workshop immediately.
In some states, you must immediately visit a qualified specialist workshop as soon as the yellow Check Engine warning lamp lights up. This is due to the legal require-
ments in effect in these states. If in doubt, check whether such legal regulations
apply in the state in which you are currently driving.
Vehicles with a diesel engine: the fuel tank has been run dry (
Ypage 158).
XStart the engine three to four times after refueling.
If the yellow Check Engine warning lamp goes out, emergency running mode is
canceled. The vehicle need not be checked.
8N The yellow reserve fuel warning lamp lights up while the engine is running.
The fuel level has dropped into the reserve range.
XRefuel at the nearest gas station.
8N The yellow reserve fuel warning lamp flashes while the vehicle is in motion.
In addition, the ;Check Engine warning lamp may light up.
The fuel filler cap is not closed correctly or the fuel system is leaking.
XCheck that the fuel filler cap is correctly closed.
XIf the fuel filler cap is not correctly closed: close the fuel filler cap.
XIf the fuel filler cap is closed:visit a qualified specialist workshop.
?NThe red coolant warning lamp lights up while the engine is running and the
coolant temperature gauge is at the start of the scale.
The temperature sensor for the coolant temperature gauge is malfunctioning.
The coolant temperature is no longer being monitored. There is a risk of engine
damage if the coolant temperature is too high.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions. Do not continue driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 161).
XConsult a qualified specialist workshop.
Warning and indicator lamps in the instrument cluster265
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 defective.
The coolant is too hot and the engine is no longer being cooled sufficiently.
XObserve the additional display messages in the multifunction display.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 161).
XLeave 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 306).
XIf you have to add coolant frequently, have the engine cooling system checked.
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 coolant temperature gauge is below the
red marking. Otherwise, the engine could be damaged.
XDrive to the nearest qualified specialist workshop.
XAvoid heavy loads on the engine as you do so, e.g. driving in mountainous terrain
and stop-and-go traffic.
?N The red coolant warning lamp comes on while the engine is running. A warning
tone also sounds.
The coolant temperature gauge has reached the red marking. The airflow to the
engine radiator may be blocked or the coolant level may be too low.
GWARNING
The engine is not being cooled sufficiently and may be damaged.
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.
XObserve the additional display messages in the multifunction display.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 161).
XLeave 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 306).
XIf you have to add coolant frequently, have the engine cooling system checked.
XMake sure that the air supply to the engine radiator is not blocked, e.g. by snow,
slush or ice.
266Warning and indicator lamps in the instrument cluster
On-board computer and displays

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
Tire pressures that are too low pose the following hazards:
Rthey may burst, especially as the load and vehicle speed increase
Rthey may wear excessively and/or unevenly, which may greatly impair tire trac-
tion
Rthe driving characteristics, as well as steering and braking, may be greatly
impaired
There is a risk of an accident.
XStop the vehicle without making any sudden steering or braking maneuvers. Pay
attention to the traffic conditions as you do so.
XSecure the vehicle against rolling away (Ypage 161).
XObserve the additional display messages in the multifunction display.
XCheck the tires and, if necessary, follow the instructions for a flat tire
(Ypage 317).
XCheck the tire pressure (Ypage 342).
XIf necessary, correct the tire pressure.
hN The yellow tire pressure monitor warning lamp (pressure loss/malfunction)
flashes for approximately one minute and then remains lit.
The tire pressure monitor is malfunctioning.
GWARNING
The system is possibly unable to recognize or register low tire pressure.
There is a risk of an accident.
XObserve the additional display messages in the multifunction display.
XVisit a qualified specialist workshop immediately.
268Warning and indicator lamps in the instrument cluster
On-board computer and displays

Adding favorites
Adding predefinedfavorites
Example: favoritesarranged in on erow
:
Adds ane wfavorite
;Renames aselected favorite
=Moves aselected favorite
?Deletes aselected favorite
XPress th eg button.
The favorite sare displayed.
These are arranged in either on eor two rows,
eac hwit hfiv etiles.
XFavorites ar earranged in one row: slide
6 thecontroller .
The men ubar is shown.
XSelec tReassign.
The categorie sare displayed.
XSelec t acategory.
The favorite sare displayed.
XSelec t afavorite .
XAdd a favorite at th edesired position .
If afavorite has already been added at this
position ,it will be overwritten.
XFavorites ar earranged in one row: slide
6 or5 thecontroller .
XTo select WAdd:tur nand press th econ-
troller .
The categorie sand predefine dfavorite sare
displayed.
XSelec t acategory.
The favorite sare displayed.
XSelec t afavorite .
XAdd a favorite at th edesired position .
If afavorite has already been added at this
position ,it will be overwritten.
Adding you rown favorites
XSelec tVehicl eQClimate Contro l.
XPress and hold theg buttonuntil th e
favorite sare displayed.
XAd d a favorite at th edesired position .
If afavorite has already been added at this
position ,it will be overwritten.
Climate control settings
Gene ral notes
You can adjust th eclimat econtrol setting s
usin gth eclimat econtrol bar or th eclimat econ-
trol menu.
Importan tclimat econtrol function scan be set
in th eclimat econtrol bar:
RTemperatur e
RAirflow
RAir distribution
The climat econtrol bar is visible in mos tdis-
plays.
You can fin dall available climat econtrol func-
tion sin th eclimat econtrol menu. You can use
th eclimat econtrol bar to switch to th eclimat e
control menu.
Overview
Climate control bar (COMAND)
:
Adjusts temperature, air distribution on th e
lef tand airflow, displays th ecurren tsetting s
;Calls up th eclimat econtrol menu, displays
th ecurren tcoolin gand climat emod eset -
ting s
=Adjusts temperature and air distribution on
theright ,displays th ecurren tsetting s
There may be fewer setting sor none depending
on your vehicle's equipment.
274Operating system
Multimedia system

The Bluetooth®device names for all of one man-
ufacturer's products might be identical. To
make it possible to clearly identify your mobile
phone, change the device name (see the man-
ufacturer's operating instructions).
If the mobile phone supports the PBAP (Phone
Book Access Profile) and MAP (M essage
Access Profile) Bluetooth
®profiles, the follow-
ing information will be transmitted after you
connect:
RPhone book
RCall lists
RMessages
iFurther information on suitable mobile
phones can be obtained on the Internet at:
http://www.mercedes-benz.com/
connect
iIn the USA, you can get in touch with the
Mercedes-Benz Customer Assistance Center
on 1-800-FOR-MERCedes (1-800-367-6372).
In Canada, you can get in touch with the Cus-
tomer Relations Center on 1-800-387-0100.
Searching for and authorizing a mobile
phone
Before using your mobile phone with the multi-
media system for the first time, you will need to
search for the phone and then authorize (con-
nect) it. Depending on the mobile phone, author-
ization either takes place by means of Secure
Simple Pairing or by entering a passkey. The
multimedia system automatically makes the
procedure that is relevant for your mobile phone available. The mobile phone is always connec-
ted automatically after authorization. Further
information on using a mobile phone with the
multimedia system (see the Digital Operator's
Manual).
If the multimedia system does not detect your
mobile phone, this may be due to particular
security settings on your mobile phone (see the
manufacturer's operating instructions).
Only one mobile phone can be connected to the
multimedia system at any one time.
Searching for a mobile phone
Multimedia system:
XSelect PhoneQConnectDeviceQSearch for PhonesQStartSearch.
The available mobile phones are displayed. Symbols in the device list
Sym-
bolExplanation
ÏNew mobile phone found, not yet
authorized.
ÑMobile phone is authorized, but is
not connected.
#Mobile phone is authorized and
connected.
Connecting a mobile phone
Authorization using Secure Simple Pairing:
XSelect mobile phone.
A code is displayed in the multimedia system
and on the mobile phone.
XIf codes match:
selectYeson the multimedia
system.
XConfirm code on the mobile phone. Depend-
ing on the mobile phone used, confirm the
connection to the multimedia system and for
the PBAP and MAP Bluetooth
®profiles. The
prompt to confirm may take up to two
minutes to be displayed (see the manufactur-
er's operating instructions).
XIf the codes are different: selectNoon the
multimedia system.
The process is canceled.
Repeat authorization.
Authorization by entering a passkey (passcode):
XSelect Bluetooth®name of the mobile phone.
The input menu for the passkey is displayed.
XChoose a one to sixteen-digit number combi- nation as a passkey.
XEnter the passkey on the multimedia system.
XPress ¬to confirm.
XEnter and confirm the passkey on the mobile
phone. Depending on the mobile phone used,
confirm the connection to the multimedia sys-
tem and for the PBAP and MAP Bluetooth
®
profiles. The prompt to confirm may take up
to two minutes to be displayed (see the man-
ufacturer's operating instructions).
Switching between mobile phones
If you have authorized more than one mobile
phone, you can switch between the individual
phones.
278Operating system
Multimedia system