2012 MERCEDES-BENZ C-Class SEDAN Sensors

Display messagesPossible causes/consequences and M SolutionsG
Tele Aid
InoperativeUSA only: one or more of the main functions in the mbrace system
are malfunctioning.
Canada only: one or more of the main functions of the TELEAID
system are malfunctioning.XUSA only: have the mbrace system checked at a qualified
specialist workshop.XCanada only: have the TELEAID system checked at a qualified
specialist workshop.PRE-SAFE
Function Currently
Limited See Oper.
ManualGRisk of accident
PRE-SAFE ®
Brake is temporarily inoperative if:
R the DISTRONIC PLUS cover in the radiator grill is dirty.
R the sensors in the bumpers are dirty.
R its function is impaired due to heavy rain or snow.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
R you switch off ESP ®
(AMG vehicles only).
R the system is outside the operating temperature range.
R the on-board voltage is too low.
PRE-SAFE ®
Brake is operational again and the display message
disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R you switch ESP ®
on again (AMG vehicles only).
R the system is within the operating temperature range.
If the display message continues to be displayed:
XClean the DISTRONIC PLUS cover in the radiator grill
( Y page 287).XClean the bumpers ( Y page 287).XRestart the engine.XWait until the battery is sufficiently charged.PRE-SAFE
Functions Limited
See Operator's
ManualGRisk of accident
PRE-SAFE ®
Brake is defective. BAS PLUS or the distance warning
signal may also have failed.
XVisit a qualified specialist workshop.218Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsRadar Sensors
Deactivated See
Operator's ManualThe radar sensor system is deactivated.XSwitch on the radar sensor system ( Y page 208).Lane Keeping
Assist Currently
Unavailable. See
Operator's Manual
or Lane Keeping
Assist Currently
Unavailable. See
Operator's ManualLane Keeping Assist or Active Lane Keeping Assist is deactivated
and temporarily inoperative if:
R the windshield is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
R there are no lane markings for a longer period.
R the lane markings are worn, dark or covered, for example by dirt
or snow.
Lane Keeping Assist or Active Lane Keeping Assist is operational
again and the display message disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system recognizes that the camera is fully operational again.
If the display message continues to be displayed:XClean the windshield.Lane Keeping
Assist Inoperative
or Active Lane
Keeping Assist
InoperativeLane Keeping Assist or Active Lane Keeping Assist is defective.XVisit a qualified specialist workshop.Display messages229On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsBlind Spot Assist
Currently
Unavailable See
Operator's Manual
or Active Blind
Spot Assist
Currently
Unavailable See
Operator's ManualBlind Spot Assist or Active Blind Spot Assist is temporarily
inoperative if:
R the sensors are dirty.
R its function is impaired due to heavy rain or snow.
R the radar sensor system is outside the operating temperature
range.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
The yellow 9 indicator lamps also light up in the exterior
mirrors.
Blind Spot Assist or Active Blind Spot Assist is operational again
and the display message disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R the radar sensor system is back within the operating
temperature range.
If the display message continues to be displayed:XClean the sensors ( Y page 287).XRestart the engine.Blind Spot Assist
Inoperative or
Active Blind Spot
Assist InoperativeBlind Spot Assist or Active Blind Spot Assist is defective.
The yellow 9 indicator lamps also light up in the exterior
mirrors.XVisit a qualified specialist workshop.Parking Guidance
InoperativeParking Guidance is malfunctioning ( Y page 178).XRestart the engine.
If the display message continues to be displayed:
XVisit a qualified specialist workshop.230Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsParking Guidance
CanceledParking Guidance has been deactivated because:
R the vehicle is skidding.
R the sensors are dirty.
R a malfunction has occurred.
A warning tone also sounds.XReactivate Parking Guidance later ( Y page 178).
If the parking space symbol is not displayed in the multifunction
display when you are driving at a speed of less than 19 mph
(30 km/h):
XClean the sensors ( Y page 287).XRestart the engine.
If the parking space symbol is still not displayed in the
multifunction display when you are driving at a speed of less than
19 mph (30 km/h):
XVisit a qualified specialist workshop.Parking Guidance has been deactivated because you are no longer
following the recommended path.XPark again and, while doing so, observe the display messages
in the multifunction display.Parking Guidance
FinishedThe vehicle is parked. A warning tone also sounds.
The display message disappears automatically.DISTRONIC PLUS
OffDISTRONIC PLUS has been deactivated ( Y page 161). If it was
deactivated automatically, a warning tone also sounds.DISTRONIC PLUS
Now Available DISTRONIC PLUS is operational again after having been
temporarily unavailable. You can now reactivate DISTRONIC PLUS
( Y page 161).Display messages231On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsDISTRONIC PLUS
Currently
Unavailable See
Operator's ManualDISTRONIC PLUS is deactivated and is temporarily inoperative if:
R the DISTRONIC PLUS cover in the radiator grill is dirty.
R its function is impaired due to heavy rain or snow.
R the sensors in the bumpers are dirty.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
A warning tone also sounds.
DISTRONIC PLUS is operational again and the display message
disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R the system is within the operating temperature range.
If the display message continues to be displayed:XClean the DISTRONIC PLUS cover in the radiator grill
( Y page 287).XClean the bumpers ( Y page 287).XRestart the engine.DISTRONIC PLUS
InoperativeDISTRONIC PLUS is defective. BAS PLUS (Brake Assist PLUS) and
PRE-SAFE ®
Brake may be inoperative as well.
A warning tone also sounds.XVisit a qualified specialist workshop.DISTRONIC PLUS
OverrideYou have depressed the accelerator pedal. DISTRONIC PLUS is no
longer controlling the speed of the vehicle.XTake your foot off the accelerator pedal.DISTRONIC PLUS
--- mphAn activation condition for DISTRONIC PLUS is not fulfilled.XCheck the activation conditions for DISTRONIC PLUS
( Y page 161).232Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsCheck Tire
Pressure SoonGRisk of accident
The tire pressure loss warning system has detected a significant
loss in pressure.
A warning tone also sounds.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XCheck the tires and, if necessary, change the wheel
( Y page 334).XCheck the tire pressures and, if necessary, set to the correct
tire pressure.XRestart the tire pressure loss warning system when the tire
pressure is correct ( Y page 317).Check Tire Pressure
Then Restart Run
Flat IndicatorThe tire pressure loss warning system generated a display
message and has not been restarted since.XSet the correct tire pressure in all four tires.XRestart the tire pressure loss warning system ( Y page 317).Run Flat Indicator
InoperativeThe tire pressure loss warning system is defective.XVisit a qualified specialist workshop.Tire pressures
will be displayed
after driving a
few minutesThe tire pressure monitor is measuring the tire pressure.XDrive on.
The tire pressures appear in the multifunction display after you
have been driving for a few minutes.Tire Press. Monitor
InoperativeThe tire pressure monitor is defective.XVisit a qualified specialist workshop.Tire Press. Monitor
Inoperative No
Wheel SensorsThe wheels mounted do not have a suitable tire pressure sensor.
The tire pressure monitor is deactivated.XMount wheels with suitable tire pressure sensors.
The tire pressure monitor is activated automatically after driving
for a few minutes.234Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsCheck
TiresGRisk of accident
The tire pressure in one or more tires has dropped significantly.
The wheel position is displayed in the multifunction display.
A warning tone also sounds.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XCorrect the tire pressure ( Y page 319).XIf necessary, change a wheel ( Y page 334).Caution:
Tire MalfunctionGRisk of accident
The tire pressure in one or more tires has dropped suddenly. The
wheel position is displayed in the multifunction display.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XIf necessary, change a wheel ( Y page 334).Correct
Tire PressureThe 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 pressures at the next opportunity. If necessary,
correct the tire pressure ( Y page 319).XRestart the tire pressure monitor ( Y page 321).Tire Press.
Sensor(s) MissingThere is no signal from the tire pressure sensor of one or several
wheels. The pressure of the affected tire is not displayed in the
multifunction display.XHave the defective tire pressure sensor replaced at a qualified
specialist workshop.Tire Press. Monitor
Currently Unavail.Due to a source of radio interference, no signals can be received
from the wheel sensors. The tire pressure monitor is temporarily
malfunctioning.XDrive on.
The tire pressure monitor restarts automatically as soon as the
problem has been solved.h
Tire Press.
Warning Caution
Tire MalfunctionGRisk of accident
The tire pressure in one or more tires has dropped suddenly.
A warning tone also sounds.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XIf necessary, change a wheel ( Y page 334).Display messages235On-board computer and displaysZ

XFold the wiper arms away from the
windshield.XCarefully clean the wiper blades with a
damp cloth.XFold the windshield wipers back again
before switching on the ignition.
! Hold the wiper arm securely when folding
back. The windshield could be damaged if
the wiper arm smacks against it suddenly.
Cleaning the exterior lighting
XClean the plastic lenses of the exterior
lights with a wet sponge and a mild cleaning
agent, e.g. Mercedes-Benz car shampoo or
cleaning cloths.
! Only use cleaning agents or cleaning
cloths which are suitable for plastic light
lenses. Unsuitable cleaning agents or
cleaning cloths could scratch or damage
the plastic light lenses.
Cleaning the sensors
XClean sensors : of the driving systems
with water, car shampoo and a soft cloth.
! When cleaning the sensors with a power
washer, maintain a distance between the
vehicle and the nozzle of the power washer
of at least 11.8 in (30 cm). Information
about the correct distance is available from
the equipment manufacturer.
Cleaning the rear view cameraXUse clear water and a soft cloth to clean
camera lens :.
!
Do not clean the camera lens and the area
around the rear view camera with a power
washer.
Cleaning the exhaust tail pipes
Impurities combined with the effects of road
grit and corrosive environmental factors may
cause flash rust to form on the surface. You
can restore the original shine of the exhaust
tail pipe by cleaning it regularly, especially in
winter and after washing.
! Do not clean the exhaust tail pipes with
alkaline-based cleaning agents, such as
wheel cleaner.
XClean the exhaust tail pipes with a chrome
care product tested and approved by
Mercedes-Benz.Care287Maintenance and careZ