2017 MERCEDES-BENZ GLC brake sensor

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 ] .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 154).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 radiationR
th e system is outside th e operating temperature rangeR
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 154).X
Restart th e engine. Display messages 23 3
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 snowR
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 radiationR
th e system is outside th e operating temperature rangeR
th e on-boar d voltag e is to o lowR
Mercedes-AMG vehicles: ES P ®
is deactivated
Whe n th e causes state d abov e no longer apply, th e display message
disappears.
PRE ‑ SAFE ®
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 154).X
Restart th e engine.X
Mercedes-AMG vehicles: switch ES P ®
on again ( Y
page 71).
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.234
Display messages
On-board computer and displays

Display messages
Possible causes/consequences and P Solutions
Radar Sensor s Dirty
See Operator' s Man ‐
ual The radar sensor system is malfunctioning .
Possibl e causes are: R
Dirt on sensor sR
Heavy rain or snow R
Whe n drivin g on inter-urban roads without traffic or infrastructure,
e.g. in desert-like area s
At least on e drivin g system or drivin g safet y system is malfunctioning
or is temporarily unavailable :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 .
Once th e caus e of th e problem is no longer present, th e drivin g and
drive safet y systems will be available again . The display message dis-
appears.
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 154).X
Switc h off th e engine.X
Clean all sensor s ( Y
page 315).X
Restart th e engine.
The display message disappears.
u SRS Malfunction Ser ‐
vic e Required The restrain t system is malfunctioning . 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 43) .
u Front Lef t Malfunc‐
tio n Servic e
Required or Front
Right Malfunction
Servic e Required The restrain t system is malfunctioning at th e fron t on th e lef t or right .
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. Display messages 23 5
On-board computer and displays Z

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 ^ or [ .X
Shift th e transmission to position ] or \\ .
Apply Brake to
Shift fro m 'P' You hav e attempte d to shift th e transmission to position [ , ^ or \\
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 ] or \\ 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 ^ , \\ or [ .
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 ] .X
Secur e th e vehicl e against rollin g away ( Y
page 154).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 ] .252
Display messages
On-board computer and displays

! Clean the water drainage channels of the
windshield and the rear window at regular
intervals. Deposits such as leaves, petals and
pollen may under certain circumstances pre-
vent water from draining away. This can lead
to corrosion damage and damage to elec-
tronic components. X
Clean the inside and outside of the windows
with a damp cloth and a cleaning product that
is recommended and approved by Mercedes-
Benz.
Cleaning wiper blades
G WARNING
You could become trapped by the windshield
wipers if they start moving while cleaning the
windshield or wiper blades. There is a risk of
injury.
Always switch off the windshield wipers and
the ignition before cleaning the windshield or
wiper blades.
! Do not pull the wiper blade. Otherwise, the
wiper blade could be damaged.
! Do not clean wiper blades too often and do
not rub them too hard. Otherwise, the graph-
ite coating could be damaged. This could
cause wiper noise.
! Hold the wiper arm securely when folding
back. The windshield could be damaged if the
wiper arm smacks against it suddenly. X
Fold the windshield wiper arms away from the
windshield ( Y
page 120).X
Carefully clean the wiper blades with a damp
cloth. X
Fold the windshield wiper arms back again
before switching on the ignition.
Cleaning the exterior lighting
! 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 len-
ses. X
Clean the plastic lenses of the exterior light-
ing using a wet sponge and a mild cleaning
agent, e.g. Mercedes-Benz car shampoo or
cleaning cloths. Cleaning the mirror turn signals
! Only use cleaning agents or cleaning cloths
that are suitable for plastic lenses. Unsuitable
cleaning agents or cleaning cloths could
scratch or damage the plastic lenses of the
mirror turn signals. X
Clean the plastic lenses of the mirror turn sig-
nals in the exterior mirror housing using a wet
sponge and mild cleaning agent, e.g.
Mercedes-Benz car shampoo or cleaning
cloths.
Cleaning the side running board
! Do not clean the aluminum inserts of the
side running board with alkaline or acidic
cleaners, such as wheel cleaner. Do not use
acidic wheel cleaners to remove brake dust.
The aluminum inserts could otherwise be
damaged.
Cleaning the sensors
! If you clean the sensors with a power
washer, make sure that you keep a distance
of at least 11.8 in (30 cm) between the vehicle
and the power washer nozzle. Information
about the correct distance is available from
the equipment manufacturer.
X
Clean sensors C of the driving systems with
water, car shampoo and a soft cloth. Care 315
Maintenance and care Z