2016 MERCEDES-BENZ C CLASS brake sensor

If a course-correcting brake application occurs,
red warning lamp C flashes in the exterior mir-
ror and a dual warning tone sounds. In addition,
display D underlining the danger of a side col-
lision appears in the multifunction display.
In very rare cases, the system may make an
inappropriate brake application. A course-cor-
recting brake application may be interrupted at
any time if you steer slightly in the opposite
direction or accelerate.
The course-correcting brake application is avail-
able in the speed range between 20 mph
(30 km/h) and 120 mph (200 km/h).
Either no braking application, or a course-cor-
recting brake application adapted to the driving
situation occurs if: R
there are vehicles or obstacles, e.g. crash
barriers, located on both sides of your vehicle. R
a vehicle approaches you too closely at the
side. R
you have adopted a sporty driving style with
high cornering speeds. R
you clearly brake or accelerate. R
a driving safety system intervenes, e.g. ESP ®
or PRE-SAFE ®
Brake.R
ESP ®
is switched off.R
a loss of tire pressure or a defective tire is
detected.
Switching on Active Blind Spot Assist X
Make sure that Active Blind Spot Assist is
activated in the on-board computer
( Y
page 248).X
Turn the SmartKey to position 2 in the ignition
lock.
Warning lamps C in the exterior mirrors light
up red for approximately 1.5 seconds. Gray
radar waves propagating backwards appear
next to the vehicle in the assistance display in
the multifunction display. Active Lane Keeping Assist General notes
Active Lane Keeping Assist monitors the area in
front of your vehicle by means of multifunction
camera C at the top of the windshield. Various
different areas to the front, rear and side of your
vehicle are also monitored with the aid of the
radar sensor system. Active Lane Keeping
Assist detects lane markings on the road and
can warn you before you leave your lane unin-
tentionally. If you do not react to the warning, a
lane-correcting application of the brakes can
bring the vehicle back into the original lane.
Important safety notes If you fail to adapt your driving style, Active Lane
Keeping Assist can neither reduce the risk of
accident nor override the laws of physics. Active
Lane Keeping Assist cannot take account of
road and weather conditions. It may not recog-
nize traffic situations. Active Lane Keeping
Assist is only an aid. You are responsible for the
distance to the vehicle in front, for vehicle
speed, for braking in good time and for staying in
your lane.
Active Lane Keeping Assist cannot continuously
keep your vehicle in its lane.
G WARNING
Active Lane Keeping Assist cannot always
clearly detect lane markings.
In such cases, Active Lane Keeping Assist
can: R
give an unnecessary warning and then
make a course-correcting brake application
to the vehicle R
not give a warning or intervene
There is a risk of an accident.222
Driving systems
Driving and parking

Always pay particular attention to the traffic
situation and keep within the lane, especially
if Active Lane Keeping Assist alerts you. Ter-
minate the intervention in a non-critical driv-
ing situation.
The system may be impaired or may not function
if: R
there is poor visibility, e.g. due to insufficient
illumination of the road, or due to snow, rain,
fog or spray R
there is glare, e.g. from oncoming traffic, the
sun or reflections (e.g. when the road surface
is wet) R
the windshield is dirty, fogged up, damaged or
covered, for instance by a sticker, in the vicin-
ity of the camera R
the radar sensors in the front or rear bumpers
or the radiator trim are dirty, e.g. obscured by
snow R
there are no, several or unclear lane markings
for a lane, e.g. in areas with road construction
work R
the lane markings are worn away, dark or cov-
ered up, e.g. by dirt or snow R
the distance to the vehicle in front is too small
and the lane markings thus cannot be detec-
ted R
the lane markings change quickly, e.g. lanes
branch off, cross one another or merge R
the road is narrow and winding R
there are strong shadows cast on the road
If no vehicle is detected in the adjacent lane and
broke n lane markings are detected, no lane-cor-
re
cting brake application is made.
Warning vibration in the steering wheel
A warning may be given if a front wheel passes
over a lane marking. It will warn you by means of
intermittent vibration in the steering wheel for
up to 1.5 second s.
Lane -correcting brake application
If you leave your lane, under certain circumstan-
ces the vehicle will brake briefly on one side.
This is meant to assist you in bringing the vehicle
back to the original lane. G WARNING
A lane-correcting brake application cannot
always bring the vehicle back into the original
lane. There is a risk of an accident.
Always steer, brake or accelerate yourself,
especially if Active Lane Keeping Assist warns
you or makes a lane-correcting brake appli-
cation.
If a lane-correcting brake application occurs,
display C appears in the multifunction display.
The brake application also slightly reduces vehi-
cle speed.
This function is available in the range between
40 mph and 120 mph (60 km/h and 200 km/h).
A lane-correcting brake application can be made
after driving over a lane marking detected as
being solid or broken. Before this, a warning
must be given by means of intermittent vibration
in the steering wheel. In addition, a lane with
lane markings on both sides must be recog-
nized.
In the case of a broken lane marking being
detected, a lane-correcting brake application
can only be made if a vehicle has been detected
in the adjacent lane. Oncoming vehicles, over-
taking vehicles and vehicles in adjacent lanes
can be detected.
i A further lane-correcting brake application
can only occur after your vehicle has returned
to the original lane.
No lane-correcting brake application occurs if: R
you clearly and actively steer, brake or accel-
erate. R
you cut the corner on a sharp bend. R
you have switched on the turn signal. R
a driving safety system intervenes, e.g. ESP ®
,
PRE-SAFE ®
Brake or Active Blind Spot Assist.Driving systems 223
Driving and parking Z

Display messages
Possible causes/consequences and P Solutions
The yellow $ warning lamp lights up and th e red I (US A only)
or $ (Canada only) indicator lamp flashes .
It is no t possibl e to apply th e electric parking brak e manually.X
Shift th e transmission to position P .X
Visit a qualified specialist workshop .
' (USA
only)
M ( Canada
only)
Check Brake Fluid
Level There is no t enough brak e flui d in th e brak e fluid reservoir .
In addition , th e ' (US A only) or M (Canada only) warning lamp
lights up in th e instrumen t cluste r and a warning tone sounds.
G WARNIN G
The braking effec t may be impaired.
There is a ris k of an accident.X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions. Do no t continu e drivin g
under any circumstances. X
Secur e th e vehicl e against rollin g away ( Y
page 177).X
Consult a qualified specialist workshop .X
Do no t add brak e fluid . This does no t correc t th e malfunction .
& Check Brake Pad Wea r The brak e pads/linings hav e reached their wear limit.
US A only: th e ' red brak e system warning lamp is lit while th e
engin e is running. X
Visit a qualified specialist workshop .
S Inoperative On e or mor e main features of th e mbrace system are malfunctioning .X
Visit a qualified specialist workshop .
Collision Preven ‐
tio n Assist Plu s
Currently Unavaila‐
ble See Operator' s
Manual COLLISION PREVENTION ASSIST PLU S is temporarily no t operational.
Possibl e causes are: R
th e radar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti c radiation emitted by nearby TV or radi o station s or
other source s of electromagneti c radiation .R
th e system is outside th e operating temperature range.R
th e on-boar d voltag e is to o low.
Whe n th e causes state d abov e no longer apply, th e display message
disappears.
COLLISION PREVENTION ASSIST PLU S is operational again .
If th e display message does no t disappear :X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 177).X
Restart th e engine. Display messages 26 1
On-board computer and displays Z

Display messages
Possible causes/consequences and P Solutions
Collision Preven ‐
tio n Assist Plu s
Inoperative COLLISION PREVENTION ASSIST PLU S is temporarily inoperative due
to a malfunction . Adaptive Brake Assis t may also hav e failed.X
Visit a qualified specialist workshop immediately.
PRE-SAFE Inopera‐
tiv e See Operator' s
Manual Importan t function s of PRE-SAF E ®
hav e failed. Al l other occupant
safet y systems , e.g. air bags , remain available.X
Visit a qualified specialist workshop immediately.
PRE-SAFE Functions
Currently Limite d
See Operator' s Man ‐
ual PRE ‑ S AF E ®
PLU S or PRE ‑ SAFE ®
Brake is temporarily inoperative.
Possibl e causes are: R
function is impaire d due to heav y rain or snow.R
th e radar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti c radiation emitted by nearby TV or radi o station s or
other source s of electromagneti c radiation .R
Mercedes-AMG vehicles: ES P ®
is deactivatedR
th e system is outside th e operating temperature range.R
th e on-boar d voltag e is to o low.
Whe n th e causes state d abov e no longer apply, th e display message
disappears.
PRE ‑ S AF E ®
PLU S and PRE ‑ S AF E ®
Brake are operational again .
If th e display message does no t disappear :X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 177).X
Restart th e engine.X
Mercedes-AMG vehicles: switch ES P ®
on again ( Y
page 74) .
PRE-SAFE Functions
Limite d See Opera‐
tor's Manual PRE ‑ S AF E ®
PLU S or PRE ‑ SAFE ®
Brake is unavailable due to a mal-
function . BA S PLU S wit h Cross-Traffic Assis t may also hav e failed.X
Visit a qualified specialist workshop immediately.262
Display messages
On-board computer and displays

Display messages
Possible causes/consequences and P Solutions
Radar Sensor s Dirty
See Operator' s Man ‐
ual At least on e of th e followin g drivin g systems or drivin g safet y systems
is temporarily restricted or inoperative: R
PRE-SAF E ®
PLU SR
PRE-SAF E ®
BrakeR
COLLISION PREVENTION ASSIST PLU SR
Active Lan e Keepin g Assis tR
Active Blind Spot Assis tR
DISTRONI C PLU S wit h Steering Assis t and Stop&Go Pilo t
If th e radar sensor system in fron t is dirty, Active Blind Spot Assis t will
no t perfor m a course-correcting brak e application .
Possibl e causes are: R
th e sensor s in th e radiato r trim and/o r in th e bumpers are dirtyR
th e function of th e drivin g system or drivin g safet y system is
impaire d due to heav y rain or snow
A warning tone also sounds.
Whe n th e causes state d abov e no longer apply, th e display message
disappears. Al l drivin g systems or drivin g safet y systems are operative
again .
If th e display message does no t disappear :X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 177).X
Switc h off th e engine.X
Clean th e sensor s in th e followin g location s ( Y
page 339):R
in th e radiato r trimR
in th e fron t bumper R
in th e rear bumper, particularly in th e middle of th e rear bumperX
Restart th e engine.
The display message disappears.
u SRS Malfunction Ser ‐
vic e Required The restrain t system is faulty. The u warning lamp also lights up in
th e instrumen t cluster.
G WARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th e event of an accident, may no t be triggered .
There is an increased ris k of injury.X
Visit a qualified specialist workshop immediately.
Fo r further information about th e restrain t system, see ( Y
page 46) .Display messages 26 3
On-board computer and displays Z

Display messages
Possible causes/consequences and P Solutions
DISTRONIC PLU S Cur ‐
rently Unavailable
See Operator' s Man ‐
ual DISTRONI C PLU S is temporarily inoperative.
Steering Assis t and Stop&Go Pilo t are temporarily inoperative.
Possibl e causes are: R
th e radar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti c radiation emitted by nearby TV or radi o station s or
other source s of electromagneti c radiation .R
th e system is outside th e operating temperature range.R
The on-boar d voltag e is to o low.
A warning tone also sounds.
Whe n th e causes state d abov e no longer apply, th e display message
disappears.
DISTRONI C PLU S is operational again .
If th e display message does no t disappear :X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 177).X
Restart th e engine.
DISTRONIC PLU S Inop‐
erativ e DISTRONI C PLU S is defective.
The followin g may hav e also failed:R
BA S PLU S wit h Cross-Traffic Assis tR
PRE-SAF E ®
BrakeR
Steering Assis t and Stop&Go Pilo t
A warning tone also sounds. X
Visit a qualified specialist workshop .
DISTRONIC PLU S Sus ‐
pended You hav e depressed th e accelerato r pedal . DISTRONI C PLU S is no
longer controllin g th e speed of th e vehicle.X
Remove your foo t from th e accelerato r pedal .
DISTRONIC PLU S
- - - mph An activation condition for DISTRONI C PLU S is no t fulfilled .X
Chec k th e activation condition s for DISTRONI C PLU S ( Y
page 186).278
Display messages
On-board computer and displays

Display messages
Possible causes/consequences and P Solutions
Tir e Pressure Moni‐
tor Inoperative No
Wheel Sensor s The wheels mounte d do no t hav e a suitable tire pressur e sensor . The
tire pressur e monitor is deactivated.X
Moun t wheels wit h suitable tire pressur e sensors.
The tire pressur e monitor is activated automatically after drivin g for
a few minutes.
Tir e Press. Monito r
Inoperative The tire pressur e monitor is faulty.X
Visit a qualified specialist workshop .
Vehicle Display messages
Possible causes/consequences and P Solutions
Shift to 'P' or 'N'
to Start Engine You hav e attempte d to start th e engin e wit h th e transmission in posi-
tion R or D . X
Shift th e transmission to position P or N .
Apply Brake to
Shift fro m 'P' You hav e attempte d to mov e th e transmission selector lever to posi-
tion D , R or N without depressing th e brak e pedal .X
Depress th e brak e pedal .
To Deselect P or N,
Depres s Brake and
Start Engine Wit h th e engin e switched off , you hav e attempte d to shift th e trans -
mission out of position P or N int o another transmission position .X
Depress th e brak e pedal .X
Start th e engine.
Transmission Not in
P Ris k of Vehicl e
Rollin g Awa y The driver's door is open or no t full y closed and th e transmission is in
position R , N or D .
A warning tone also sounds.
G WARNIN G
The vehicl e may rol l away.
There is a ris k of an accident.X
Shift th e transmission to position P .X
Secur e th e vehicl e against rollin g away ( Y
page 177).X
Clos e th e driver's door completely.
Onl y Shift to 'P'
whe n Vehicl e is Sta ‐
tionar y The vehicl e is moving .X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions.X
Shift th e transmission to position P .282
Display messages
On-board computer and displays