check engine light MERCEDES-BENZ C-Class SEDAN 2012 W204 Owner's Manual

Authorized Mercedes-Benz Centersee Qualified specialist workshop
AUTO lights
Display message ............................ 225
see Lights
Automatic headlamp mode .............. 108
Automatic transmission Automatic drive program ...............146
Changing gear ............................... 144
Display message ............................ 236
Driving tips .................................... 144
Emergency running mode ..............149
Kickdown ....................................... 144
Manual drive program ....................147
Problem (malfunction) ...................149
Program selector button ................144
Pulling away ................................... 139
Releasing the parking lock
manually ........................................ 149
Selector lever ................................ 142
Shift ranges ................................... 146
Starting the engine ........................139
Steering wheel paddle shifters ......145
Transmission position display ........143
Transmission positions ..................143
Automatic transmission
emergency mode ............................... 149
B
Back support see Lumbar support
Backup lamp
Changing bulbs .............................. 116
Display message ............................ 224
Bag hook ............................................ 258
BAS (Brake Assist System) ................. 59
Basic settings see Settings
BAS PLUS (Brake Assist System
PLUS) .................................................... 60
Battery (SmartKey) Checking .......................................... 74
Important safety notes ....................74
Replacing ......................................... 74
Battery (vehicle)
Charging ........................................ 300
Display message ............................ 227
Important safety notes ..................298
Jump starting ................................. 301
Belt
see Seat belts
Blind Spot Assist
Activating/deactivating .................205
Notes/function .............................. 183
see Active Blind Spot Assist
Brake Assist System
see BAS (Brake Assist System)
Brake fluid
Display message ............................ 217
Notes ............................................. 350
Brake fluid level ................................ 282
Brake lamps Changing bulbs .............................. 116
Display message ............................ 223
Brakes
ABS .................................................. 59
BAS .................................................. 59
BAS PLUS ........................................ 60
Brake fluid (notes) .........................350
Display message ............................ 214
Driving tips .................................... 156
High-performance brake system ....158
Important safety notes ..................156
Maintenance .................................. 157
Parking brake ................................ 154
Warning lamp ................................. 241
Breakdown
see Flat tire
see Towing away/tow-starting
Bulbs
see Changing bulbs
C
California Important notice for retail
customers and lessees ....................22
Calling up a malfunction
see Display messages
Capacities
see Technical data
Car
see Vehicle
Index5

COMANDsee separate operating instructions
Combination switch .......................... 109
Compass Calibrating ..................................... 276
Calling up ....................................... 275
Setting ........................................... 275
Consumption statistics (on-board
computer) .......................................... 199
Convenience closing feature .............. 84
Convenience opening feature ............ 84
Coolant (engine) Checking the level .........................280
Display message ............................ 225
Notes ............................................. 350
Temperature (on-board computer) . 210
Temperature gauge ........................ 194
Warning lamp ................................. 247
Cooling
see Climate control
Cornering light function
Changing bulbs .............................. 115
Display message ............................ 222
Function/notes ............................. 110
Crash-responsive emergency
lighting ............................................... 113
Cruise control Cruise control lever .......................160
Deactivating ................................... 161
Display message ............................ 233
Driving system ............................... 159
Function/notes ............................. 159
Important safety notes ..................159
LIM indicator lamp .........................160
Setting a speed .............................. 160
Storing and maintaining current
speed ............................................. 160
Cup holder
Center console .............................. 260
Important safety notes ..................259
Rear compartment .........................260
Customer Assistance Center (CAC) ... 25
Customer Relations Department ....... 25D
Dashboard see Cockpit
Data
see Technical data
Daytime running lamps
Display message ............................ 224
Switching on/off (on-board
computer) ...................................... 207
Switching on/off (switch) ..............107
Delayed switch-off
Exterior lighting (on-board
computer) ...................................... 207
Interior lighting .............................. 208
Digital speedometer ......................... 199
Display (cleaning instructions) ........ 288
Display messages Calling up (on-board computer) .....213
Driving systems ............................. 228
Engine ............................................ 225
General notes ................................ 213
Hiding (on-board computer) ...........213
KEYLESS-GO .................................. 238
Lights ............................................. 222
Safety systems .............................. 214
Service interval display ..................282
SmartKey ....................................... 238
Tires ............................................... 233
Vehicle ........................................... 236
Distance display (on-board
computer) .......................................... 204
Distance recorder ............................. 199
see Odometer
see Trip odometer
Distance warning (warning lamp) .... 249
DISTRONIC PLUS Deactivating ................................... 169
Display message ............................ 231
Displays in the multifunction
display ........................................... 168
Driving tips .................................... 170
Function/notes ............................. 161
Important safety notes ..................161
Setting the specified minimum
distance ......................................... 168
Warning lamp ................................. 249Index7

E
EASY-ENTRY feature Activating/deactivating .................209
Function/notes ............................. 100
EASY-EXIT feature
Crash-responsive ........................... 101
Function/notes ............................. 100
Switching on/off ........................... 209
EBD (electronic brake force
distribution) Display message ............................ 216
Function/notes ................................ 64
Electrical fuses
see Fuses
Electronic brake force distribution
see EBD (electronic brake force
distribution)
Electronic Stability Program
see ESP ®
(Electronic Stability Program)
Electronic Traction System
see ETS/4ETS (Electronic
Traction System)
Emergency release
Driver's door .................................... 79
Fuel filler flap ................................. 151
Trunk ............................................... 82
Vehicle ............................................. 79
Emergency spare wheel
Storage location ............................ 293
Emergency Tensioning Devices
Function ........................................... 52
Safety guidelines ............................. 37
Emissions purification
Service and warranty information ....21
Engine
Check Engine warning lamp ........... 246
Display message ............................ 225
Emergency starting ........................305
Engine number ............................... 344
Irregular running ............................ 141
Starting problems ..........................141
Starting the engine with the
SmartKey ....................................... 139
Starting with KEYLESS-GO .............139
Switching off .................................. 153
Engine electronics
Problem (malfunction) ...................141Engine oil
Adding ........................................... 279
Additives ........................................ 349
Checking the oil level ..................... 279
Checking the oil level using the
dipstick .......................................... 279
Display message ............................ 227
Filling capacity ............................... 346
Notes about oil grades ................... 349
Notes on oil level/consumption ....279
Temperature (on-board computer) . 210
Viscosity ........................................ 349
ESP ®
(Electronic Stability
Program) AMG menu (on-board computer) ...210
Deactivating/activating (AMG
vehicles) .......................................... 62
Deactivating/activating (except
AMG vehicles) ................................ 204
Deactivating/activating (notes;
except AMG vehicles) ......................62
Display message ............................ 214
ETS/4ETS ........................................ 61
Function/notes ................................ 61
Important safety information ...........61
Warning lamp ................................. 243
ETS/4ETS (Electronic Traction
System) ................................................ 61
Exhaust check ................................... 156
Exhaust tail pipe (cleaning
instructions) ...................................... 287
Exterior lighting see Lights
Exterior mirrors
Adjusting ....................................... 101
Dipping (automatic) .......................102
Folding in/out (automatically) .......102
Folding in/out (electrically) ...........101
Folding in when locking (on-board
computer) ...................................... 209
Out of position (troubleshooting) ...102
Setting ........................................... 102
Storing settings (memory
function) ........................................ 103
Storing the parking position ..........102
Eyeglasses compartment ................. 255Index9

Stowage well beneath the trunk
floor .................................................... 258
Summer opening see Convenience opening feature
Summer tires ..................................... 312
Sun visor ............................................ 260
Supplemental Restraint System see SRS (Supplemental Restraint
System)
Surround lighting (on-board
computer) .......................................... 207
Switching air-recirculation mode
on/off ................................................. 130
Switching off the alarm (ATA) ............ 67
T
Tachometer ........................................ 195
Tail lamps Display message ............................ 223
Tank
see Fuel tank
Tank content
Fuel gauge ....................................... 29
Technical data
Notes ............................................. 342
Tires/wheels ................................. 335
Vehicle data ................................... 351
TELEAID
Call priority .................................... 268
Display message ............................ 218
Downloading destinations
(COMAND) ..................................... 269
Emergency call .............................. 266
Important safety notes ..................264
Locating a stolen vehicle ...............270
MB info call button ........................268
Remote vehicle locking ..................270
Roadside Assistance button ..........267
Search & Send ............................... 269
Self-test ......................................... 265
System .......................................... 265
Vehicle remote unlocking ..............269
Telephone
Accepting a call ............................. 203
Display message ............................ 237
Menu (on-board computer) ............202
Number from the phone book ........ 203
Redialing ........................................ 203
Rejecting/ending a call .................203
Temperature
Coolant .......................................... 194
Coolant (on-board computer) ......... 210
Engine oil (on-board computer) ...... 210
Outside temperature ...................... 195
Setting (climate control) ................128
Theft deterrent systems
ATA (Anti-Theft Alarm system) .........67
Immobilizer ...................................... 66
Through-loading feature ................... 256
Tilt/sliding sunroof see Sliding sunroof
Timing (RACETIMER) ......................... 211
Tiredness assistant see ATTENTION ASSIST
Tire pressure
Calling up (on-board computer) .....319
Checking manually ........................317
Display message ............................ 233
Maximum ....................................... 316
Notes ............................................. 315
Pressure loss warning ....................317
Recommended ............................... 313
Tire pressure monitoring system
Function/notes ............................. 319
Restarting ...................................... 321
Warning lamp ................................. 250
Tires
Aspect ratio (definition) .................333
Average weight of the vehicle
occupants (definition) ....................331
Bar (definition) ............................... 331
Characteristics .............................. 331
Checking ........................................ 311
Definition of terms .........................331
Direction of rotation ......................334
Display message ............................ 233
Distribution of the vehicle
occupants (definition) ....................334
DOT, Tire Identification Number
(TIN) ............................................... 330
DOT (Department of
Transportation) (definition) ............331
GAWR (Gross Axle Weight Rating)
(definition) ..................................... 332Index17

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 24).
Occupant safety
Overview of occupant safety
In this section, you will learn the most
important facts about the restraint system
components of the vehicle.
The restraint system consists of:
R seat belts
R child restraint systems
R LATCH-type (ISOFIX) child seat anchors
Additional protection is provided by:
R SRS (Supplemental Restraint System)
R NECK-PRO head restraints/NECK-PRO
luxury head restraints
R Air bag system components with:
- PASSENGER AIR BAG OFF indicator lamp
- front-passenger seat with Occupant
Classification System (OCS)
The different air bag systems work
independently of each other. The protective
functions of the system work in conjunction
with each other. Not all air bags are deployed
in an accident.
GWARNING
Modifications to or work improperly
conducted on restraint system components
or their wiring, as well as tampering with
interconnected electronic systems, can lead
to the restraint systems no longer functioning
as intended.
Air bags or Emergency Tensioning Devices
(ETDs), for example, could deploy
inadvertently or fail to deploy in accidents
although the deceleration threshold for air
bag deployment is exceeded. Therefore,
never modify the restraint systems. Do not
tamper with electronic components or their
software.
i See "Children in the vehicle"
( Y page 53) for more information on
infants and children traveling with you in
the vehicle and restraints for infants and
children.
SRS (Supplemental Restraint System)
Introduction
SRS consists of:
R the 6 SRS warning lamp
R air bags
R air bag control unit (with crash sensors)
R Emergency Tensioning Devices
R belt force limiters
SRS reduces the risk of occupants coming
into contact with the vehicle's interior in the
event of an accident. It can also reduce the
effect of the forces to which occupants are
subjected during an accident.
SRS warning lamp
SRS functions are checked regularly when
you switch on the ignition and when the
engine is running. Therefore, malfunctions
can be detected in good time.
The 6 SRS warning lamp in the instrument
cluster lights up when the ignition is switched
on. It goes out no later than a few seconds
after the engine is started.
The SRS components are in operational
readiness when the 6 SRS warning lamp
is not lit while the engine is running .
36Occupant safetySafety

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 24).
SmartKey
Important safety notes
GWARNING
When leaving the vehicle, always remove the
SmartKey from the ignition lock. Always take
the SmartKey with you and lock the vehicle.
Do not leave children unsupervised in the
vehicle, even if they are secured in a child
restraint system, and do not give them access
to an unlocked vehicle. A child's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury. They could:
R injure themselves on vehicle parts
R be seriously or fatally injured by extreme
heat or cold
R injure themselves or have an accident with
vehicle equipment that may still be in
operation even after the SmartKey has
been removed from the ignition, such as the
seat adjustment, steering wheel
adjustment or memory function.
If children open a door, they could cause
severe or even fatal injury to other persons; if
they get out of the vehicle, they could injure
themselves when doing so or be seriously or
even fatally injured by any passing traffic.
Do not expose the child restraint system to
direct sunlight. The child restraint system's
metal parts, for example, could become very
hot, and a child could be burned on these
parts.GWARNING
If a key ring is too heavy or too large, the
weight acting on the SmartKey could cause it
to turn in the ignition lock or catch on the
steering wheel. This could cause the engine
to be switched off suddenly. You could lose
control of the vehicle and cause an accident.
Do not attach any heavy or large key rings to
the SmartKey that is inserted in the ignition.
General notes
If you cannot lock or unlock the vehicle with
the SmartKey, either the battery in the
SmartKey is discharged, the SmartKey is
faulty or the starter battery is discharged.
XCheck the battery in the SmartKey and
replace it if necessary ( Y page 74).XUnlock the driver's door using the
mechanical key ( Y page 79).XLock the vehicle using the mechanical key
( Y page 79).XHave the starter battery and the battery
contacts checked at a qualified specialist
workshop.
If the SmartKey is faulty, contact Roadside
Assistance or a qualified specialist workshop.
SmartKey functions
General notes
i USA only:
This device complies with Part 15 of the
FCC Rules. Operation is subject to the
following two conditions:
1. This device may not cause harmful
interference, and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
70SmartKeyOpening/closing

ProblemPossible causes/consequences and M SolutionsThe engine cannot be
started using the
SmartKey.The on-board voltage is too low.XSwitch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
XCheck the starter battery and charge it if necessary
( Y page 298).
or
XJump-start the vehicle ( Y page 301).
or
XConsult a qualified specialist workshop.The engine cannot be
started using the
SmartKey.The steering lock is mechanically blocked.XRemove the SmartKey and reinsert it into the ignition lock. While
doing this, turn the steering wheel in both directions.The engine cannot be
started using KEYLESS-
GO. The SmartKey is in
the vehicle.A door is open. Therefore, the SmartKey cannot be detected as
easily.XClose the door and try to start the vehicle again.There is interference from a powerful source of radio waves.XStart your vehicle with the SmartKey in the ignition lock.Doors
Important safety notes
GWARNING
When leaving the vehicle, always remove the
SmartKey from the ignition lock. Always take
the SmartKey with you and lock the vehicle.
Do not leave children unsupervised in the
vehicle, even if they are secured in a child
restraint system, and do not give them access
to an unlocked vehicle. A child's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury. They could:
R injure themselves on vehicle parts
R be seriously or fatally injured by extreme
heat or cold
R injure themselves or have an accident with
vehicle equipment that may still be in
operation even after the SmartKey has
been removed from the ignition, such as the
seat adjustment, steering wheel
adjustment or memory function.
If children open a door, they could cause
severe or even fatal injury to other persons; if
they get out of the vehicle, they could injure
themselves when doing so or be seriously or
even fatally injured by any passing traffic.
Do not expose the child restraint system to
direct sunlight. The child restraint system's
metal parts, for example, could become very
hot, and a child could be burned on these
parts.GWARNING
Do not carry heavy or hard objects in the
passenger compartment or trunk unless they
are firmly secured in place.
Doors77Opening/closingZ

Manual interior lighting controlXTo switch the front interior lighting on/
off: press the c button.XTo switch the rear interior lighting on/
off: press the u button.XTo switch the reading lamps on/off:
press the p button.
Crash-responsive emergency lighting
The interior lighting is activated automatically
if the vehicle is involved in an accident.
XTo switch off the crash-responsive
emergency lighting: press the hazard
warning lamp button.
or
XLock and then unlock the vehicle using the
SmartKey.
Replacing bulbs
Important safety notes
Xenon bulbs
If your vehicle is equipped with Xenon bulbs,
you can recognize this by the following: the
cone of light from the Xenon bulbs moves
from the top to the bottom and back again
when you start the engine. For this to be
observed, the lights must be switched on
before starting the engine.
GDANGER
Xenon bulbs carry a high voltage. You could
get an electric shock and be seriously or even
fatally injured if you touch the electric
contacts on Xenon bulbs. Therefore, never
remove the cover from Xenon bulbs.
Do not change Xenon bulbs yourself, but have
them replaced at a qualified specialist
workshop which has the necessary specialist
knowledge and tools to carry out the work
required.
Mercedes-Benz recommends that you use an
authorized Mercedes-Benz Center for this
purpose. In particular, work relevant to safety
or on safety-related systems must be carried
out at a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly.
Other bulbs
There are bulbs other than the Xenon bulbs
that you cannot replace. Replace only the
bulbs listed (Y page 114). Have the bulbs that
you cannot replace yourself changed at a
qualified specialist workshop.
Mercedes-Benz recommends that you use an
authorized Mercedes-Benz Center for this
purpose. In particular, work relevant to safety
or on safety-related systems must be carried
out at a qualified specialist workshop.
If you require assistance changing bulbs,
consult a qualified specialist workshop.
Do not touch the glass tube of new bulbs with
your bare hands. Even minor contamination
can burn into the glass surface and reduce
the service life of the bulbs. Always use a lint-
free cloth or only touch the base of the bulb
when installing.
Only use bulbs of the correct type.
If the new bulb still does not light up, consult
a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly.
GWARNING
Bulbs and lamps can be very hot. You should
therefore allow them to cool down before you
change them. Otherwise, you could be burned
if you touch them.
Keep bulbs out of the reach of children.
Otherwise, they could damage the bulbs, for
example, and injure themselves.
Replacing bulbs113Lights and windshield wipersZ

XHold wiper arm : and press wiper
blade ; in the direction of the arrow until
it releases.XRemove wiper blade ;.
Installing the wiper blade
XPlace new wiper blade ; onto wiper
arm :.XHold wiper arm : and press wiper
blade ; in the opposite direction to the
arrow until it engages.XMake sure that wiper blade ; is seated
correctly.XPosition wiper blade ; parallel to wiper
arm :.XFold wiper arm : back onto the rear
window.
Problems with the windshield wipers
The windshield wipers are obstructed
Leaves or snow, for example, may be
obstructing the windshield wiper movement.
The wiper motor has been deactivated.
XFor safety reasons, you should remove the
SmartKey from the ignition lock.
or
XSwitch off the engine using the Start/Stop
button and open the driver's door.XRemove the cause of the obstruction.XSwitch the windshield wipers back on.
The windshield wipers are inoperative
The windshield wiper drive is malfunctioning.
XSelect another wiper speed on the
combination switch.XHave the windshield wipers checked at a
qualified specialist workshop.The spray nozzles are misaligned
The windshield washer fluid from the spray
nozzles no longer hits the center of the
windshield. The spray nozzles are misaligned.
XHave the spray nozzles adjusted at a
qualified specialist workshop.Windshield wipers119Lights and windshield wipersZ

ProblemPossible causes/consequences and M SolutionsThe engine is not
running smoothly and
is misfiring.There is a malfunction in the engine electronics or a mechanical
component of the engine management system.XOnly depress the accelerator pedal slightly.XHave the cause rectified immediately at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz Center.
Otherwise, non-combusted fuel may get into the catalytic
converter and damage it.The coolant
temperature gauge
shows a value above
248 ‡ (120 †).The coolant level is too low. The coolant is too hot and the engine
is no longer being cooled sufficiently.XStop as soon as possible and allow the engine and the coolant
to cool down.XCheck the coolant level ( Y page 280). Observe the warning
notes as you do so and add coolant if necessary.Automatic transmission
Important safety notes
GWARNING
It is dangerous to shift the automatic
transmission out of parking position P or
neutral position N if the engine speed is
higher than idle speed. If your foot is not firmly
on the brake pedal, the vehicle could
accelerate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and when
your right foot is firmly on the brake pedal.
GWARNING
Keep in mind that turning off the engine alone
only will shift the automatic transmission into
neutral position N automatically.
Always shift the automatic transmission into
park position P before turning off the engine.
Otherwise the vehicle could roll away which
could result in an accident and/or serious
personal injury.
Selector lever
Overview of transmission positions
Example: selector lever
PPark position with selector lever lockRReverse gearNNeutralDDrive142Automatic transmissionDriving and parking