2018 MERCEDES-BENZ GLS check engine

C
Warning lamp
If Blind Spot Assist is activated, warning lamp C
in the exterior mirrors lights up yellow at speeds
of up to 20 mph (30 km/ h) . At speeds above
20 mph (30 km/h), the warning lamp goes out
and Blind Spot Assist is operational.
If a vehicle is detected within the blind spot
monitoring range at speeds above 20 mph
(30 km/h), warning lamp C on the correspond-
ing side lights up red. This warning is always
emitted when a vehicle enters the blind spot
monitoring range from behind or from the side.
When you overtake a vehicle, the warning only
occurs if the difference in speed is less than
7 mph (12 km/h).
If you select the reverse gear, Blind Spot Assist
is not operational.
The brightness of the warning lamps is auto-
matically adapted to the brightness of the sur-
roundings.
Collision warning If a vehicle is detected in the monitoring range of
Blind Spot Assist and you switch on the corre-
sponding turn signal, a double warning tone
sounds. Red warning lamp C flashes. If the turn
signal remains on, detected vehicles are indica-
ted by the flashing of red warning lamp C .
There are no further warning tones.
Switching on Blind Spot Assist X
Make sure that Blind Spot Assist is activated
in the on-board computer ( Y
page 242).X
Turn the SmartKey to position H in the igni-
tion lock.
Warning lamps C in the exterior mirrors light
u p red for approximately 1.5 seconds and
then turn yellow. Towing a trailer When you attach a trailer, make sure you have
correctly established the electrical connection.
This can be accomplished by checking the trailer
lighting. In this event, Blind Spot Assist is deac-
tivated. The warning lamp lights up yellow in the
exterior mirrors and the Blind Spot Assist
Not Available When Towing a Trailer
See Operator's Manual message appears in
the multifunction display.
i You can deactivate the warning lamps in the
exterior mirrors.
To do so, switch off Blind Spot Assist when: R
the SmartKey is in position H in the igni-
tion lock R
the engine is not running
Lane Keeping Assist General notes
C
Lane Keeping Assist camera
Lane Keeping Assist monitors the area in front of
your vehicle with camera C , which is mounted
at the top of the windshield. Lane Keeping Assist
detects lane markings on the road and can warn
you before you leave your lane unintentionally.
This function is available in the range between
40 mph and 120 mph (60 km/h and 200 km/h).
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 seconds.
Important safety notes
G WARNING
Lane Keeping Assist cannot always clearly
detect lane markings.Driving systems 211
Driving and parking Z

Course-correcting brake application If Active Blind Spot Assist detects a risk of a lat-
eral collision in the monitoring range, a course-
correcting brake application is carried out. This
is meant to assist you in avoiding a collision.
G WARNING
A course-correcting brake application cannot
always prevent a collision. There is a risk of an
accident.
Always steer, brake or accelerate yourself,
especially if Active Blind Spot Assist warns
you or makes a course-correcting brake appli-
cation. Always maintain a safe distance at the
sides.
If a course-correcting brake application occurs,
red warning lamp C flashes in the exterior mir-
ror and a double warning tone sounds. In addi-
tion, a display underlining the danger of a side
collision 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 by countersteering slightly or acceler-
ating.
The course-correcting brake application is avail-
able in the speed range between 20 mph
(30 km/h) and 120 mph (20 0 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
the offroad program is activated (vehicles
without the Offroad Engineering package). R
the Offroad or Offroad Plus drive program is
activated (vehicles with the Off-Road Engi-
neering package). R
the LOW RANGE offroad gear is activated
(vehicles with the Offroad Engineering pack-
age). 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
( Y
page 242) is activated in the on-board
computer. X
Turn the SmartKey to position H in the igni-
tion lock.
Warning lamps C in the exterior mirrors light
up red for approximately 1.5 seconds an d
then turn yellow.
Towing a trailer When you attach a trailer, make sure you have
correctly established the electrical connection.
This can be accomplished by checking the trailer
lighting. Active Blind Spot Assist is then deacti-
vated. The indicator lamp lights up yellow in the
exterior mirrors and the Active Blind Spot
Asst. Not Available When Towing a
Trailer See Operator's Manual message
appears 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, aDriving system s 215
Dr ivi ng an d parking Z

R
is affected more by strong crosswinds R
demands more sensitive steering R
has a larger turning circle
This could impair the handling characteristics.
When towing a trailer, always adjust your speed
to the current road and weather conditions. Do
not exceed the maximum permissible speed for
your vehicle/trailer combination.
Notes on towing a trailer
General notes
! If you have a trailer tow hitch retrofitted,
changes to the cooling system and drive train
may be necessary, depending on the vehicle
type.
If you have a trailer tow hitch retrofitted,
observe the anchorage points on the chassis
frame. R
Do not exceed the legally prescribed maxi-
mum speed for vehicle/trailer combinations
in the relevant country.
This lowers the risk of an accident. R
Only install an approved trailer coupling on
your vehicle.
More information on availability and installa-
tion can be obtained at any qualified special-
ist workshop. R
The bumpers of your vehicle are not suitable
for installing detachable trailer couplings. R
Do not install hired trailer couplings or other
detachable trailer couplings on the bumpers
of your vehicle. R
If you no longer need the ball coupling,
remove it from the ball coupling recess. This
will reduce the risk of damage to the ball cou-
pling.
When towing a trailer, set the tire pressure on
the rear axle of the towing vehicle for the max-
imum load. You will find the values in the tire
pressure table in the fuel filler flap of the vehicle
( Y
page 372).
Please note that when towing a trailer, the fol-
lowing driving systems have limited availability
or are not available at all: R
Parking Assist PARKTRONIC ( Y
page 192)R
Blind Spot Assist ( Y
page 209)R
Active Lane Keeping Assist ( Y
page 215) On vehicles without level control, the height of
the ball coupling will alter according to the load
placed on the vehicle. If necessary, use a trailer
with a height-adjustable drawbar.
You will find installing dimensions and loads
under "Technical data" ( Y
page 395).
Driving tips Also observe the notes on pulling away with a
trailer ( Y
page 143).
The maximum permissible speed for vehicle/
trailer combinations depends on the type of
trailer. Before beginning the journey, check the
trailer's documents to see what the maximum
permissible speed is for your trailer. Observe the
legally permissible maximum speed in the rele-
vant country.
For certain Mercedes-Benz vehicles, the maxi-
mum permissible rear axle load is increased
when towing a trailer. See "Technical data" to
find out whether this applies to your vehicle
( Y
page 395). If you utilize any of the added
maximum rear axle load when towing a trailer,
the vehicle/trailer combination may not exceed
a maximum speed of 60 mph (100 km/h) for
reasons concerning the operating permit. This
also applies in countries in which the maximum
permissible speed for car/trailer combinations
is greater than 60 mph (100 km/h).
When towing a trailer, your vehicle's handling
characteristics will be different in comparison
with when driving without a trailer.
Use the left-hand steering wheel paddle shifter
to shift into a lower gear in good time on long
and steep downhill gradients.
This also applies if you have activated cruise
control or Distance Pilot DISTRONIC.
This will use the braking effect of the engine, so
that less braking will be required to maintain the
speed. This relieves the load on the brake sys-
tem and prevents the brakes from overheating
and wearing too quickly. If you need additional
braking, depress the brake pedal repeatedly
rather than continuously.
Driving tips
If the trailer swings from side to side: X
Do not accelerate. X
Do not counter-steer. X
Brake if necessary.Towing a trailer 225
Driving and parking Z

Most U.S. states and all Canadian provinces
require by law: R
Safety chains between the towing vehicle and
the trailer. The chains should be cross-wound
under the trailer drawbar. They must be fas-
tened to the vehicle's trailer coupling, not to
the bumper or the axle.
Leave enough play in the chains to make tight
cornering possible. R
A separate brake system for certain types of
trailer. R
Safety switch for braked trailers. Check the
specific legal requirements applicable to your
state.
If the trailer becomes detached from the tow-
ing vehicle, the safety feature triggers the
trailer brakes.
Towing a trailer There are numerous legal requirements con-
cerning the towing of a trailer, e.g. speed restric-
tions. Make sure that your car/trailer combina-
tion complies with the local regulations: R
in your place of residence R
in the location to which you are driving
The police and local authorities can provide reli-
able information.
Observe the following when towing a trailer: R
To gain driving experience and to become
accustomed to the new handling characteris-
tics, you should practice the following in a
traffic-free location: -
cornering -
stopping -
backing up R
Before driving, check: -
trailer tow hitch -
safety switch for braked trailers -
safety chains -
electrical connections -
lights -
wheels R
Adjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer. R
If the trailer has electronically controlled
brakes, pull away carefully. Brake manually using the brake controller and check whether
the brakes function correctly. R
Secure any objects on the trailer to prevent
the cargo from slipping when the vehicle is in
motion. R
When you couple up a trailer, check at regular
intervals that the load is firmly secured. If the
trailer is equipped with trailer lights and
brakes, check the trailer to ensure that these
are working. R
Bear in mind that the handling will be less
stable when towing a trailer than when driving
without one. Avoid sudden steering move-
ments. R
The vehicle/trailer combination is heavier,
accelerates more slowly, has a decreased
gradient climbing capability and a longer
braking distance.
It is more susceptible to side winds and
requires more careful steering. R
If possible, do not brake suddenly, but instead
depress the brake pedal moderately at first so
that the trailer can activate its brakes. Then
increase the pressure on the brake pedal. R
If the automatic transmission repeatedly
shifts between gears on uphill or downhill gra-
dients, shift to a lower gear using the left-hand
steering wheel paddle shifter.
A lower gear and lower speed reduce the risk
of engine failure. R
When driving downhill, shift to a lower gear to
utilize the engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if instal-
led, the trailer brakes. R
If the coolant temperature increases dramat-
ically while the air-condition ing system is
switched on, switch off the air-conditioning
system.
Coolant heat can also be dissipated by open-
ing the windows and switching the ventilation
blower and the interior temperature to the
highest level. R
When overtaking, pay particular attention to
the extended length of your vehicle/trailer
combination.
Due to the length of the vehicle/trailer com-
bination, you require additional road space in
relation to the vehicle you are overtaking
before you can change back to the original
lane.228
Towing a trailer
Driving and parking

Decoupling a trailer
G WARNING
If you uncoupl e a trailer wit h th e overrun
brake engaged, you could trap your han d
between th e vehicle and th e trailer drawbar .
There is a ris k of injury.
Do no t uncoupl e a trailer if th e overrun brake
is engaged.
G WARNING
Vehicles wit h level control:
The vehicle is lowered as soo n as you discon-
nect th e trailer cable. Thi s could result in your
limbs or those of other people that are
between th e vehicle bod y and tires or under-
neat h th e vehicle bein g trapped. There is a
ris k of injury.
Mak e sur e that nobod y is in th e immediate
vicinit y of th e whee l housings or under th e
vehicle when you disconnec t th e trailer cable.
! Do no t disconnec t a trailer wit h an engage d
overrun brake . Otherwise , your vehicle could
be damaged by th e reboundin g of th e overrun
brake .X
Shift th e transmissio n to position P .X
Apply th e vehicle' s electric parking brake .X
Start th e engine.X
Clos e th e doors and tailgate.X
Apply th e trailer's parking brake .X
Detach th e trailer cable and decoupl e th e
trailer .X
Switc h of f th e engine.
Permissible trailer loads an d drawbar
loads
Weight specifications
Maximum allowable gross mass
The gross vehicle weight of th e trailer is calcu-
lated by addin g th e weight of th e trailer to th e
weight of th e load and equipmen t on th e trailer .
You will fin d installin g dimensions and load s
under "Technical data" ( Y
page 395). Permissible noseweigh tYou will fin d installin g dimensions and load s
under "Technical data" ( Y
page 395).
Loading a trailer R
Whe n loadin g th e trailer , mak e sur e that nei-
ther th e permissible gross weight of th e trailer
no r th e gross vehicle weight are exceeded.
The permissible gross vehicle weight is indi-
cated on th e identification plat e located on
th e B-pilla r on th e driver's sid e of th e vehicle.
You can fin d th e maximum permissible values
on th e typ e plates of your vehicle and th e
trailer . Whe n calculatin g how muc h weight
th e vehicle and trailer may carry, pay atten-
tion to th e respective lowest values. R
The trailer drawbar load on th e ball couplin g
mus t be adde d to th e rea r axl e load to avoid
exceedin g th e permissible gross axl e weight .
The permissible gross vehicle weight is indi-
cated on th e identification plat e located on
th e B-pilla r on th e driver's sid e of th e vehicle.
i Mercedes-Ben z recommends a trailer load
wher e th e trailer drawbar noseweigh t
accounts fo r 8 % to 15 % of th e trailer's per -
missible gross weight .
i The weight of additional accessories , pas-
sengers, and cargo reduce s th e permissible
trailer load and drawbar load fo r your vehicle.
Checking th e vehicle an d trailer weigh tR
To chec k that th e weight s of th e towin g vehi-
cl e and th e trailer compl y wit h th e maximum
permissible values, hav e th e vehicle/trailer
combination (includin g th e driver , passen -
gers, and cargo wit h a full y lade n trailer )
weighed on a calibrated weighbridge .R
Chec k th e gross axl e weight ratin g of th e fron t
and rea r axles, th e gross weight of th e trailer
and th e trailer drawbar noseweight.
Removin g th e ball coupling X
Remov e th e sprin g cotter.X
Remov e th e bolt from th e ball couplin g
recess . X
Remov e th e ball couplin g from th e ball cou-
plin g recess .Towing a trailer 229
Driving and parking Z

Important safety notes
G WARNIN G
If you operate information systems and com-
munication equipmen t integrate d in th e vehi-
cle when driving , you may be distracte d from
th e traffic situation . You could also lose con-
trol of th e vehicle. Ther e is a ris k of an acci-
dent.
Only operate this equipmen t when th e traffic
situation permits. If you are no t sur e that this
is possible , park th e vehicl e payin g attention
to traffic condition s and operate th e equip-
men t when th e vehicl e is stationary.
You must observ e th e legal requirements for th e
country in whic h you are currentl y driving when
operating th e on-board computer.
G WARNIN G
If th e instrumen t cluste r has faile d or mal-
functioned, you may no t recognize function
restriction s in systems relevan t to safety. The
operating safet y of your vehicl e may be
impaired . Ther e is a ris k of an accident.
Drive on carefully. Hav e th e vehicl e checke d
at a qualified specialist workshop immedi-
ately.
If th e operating safet y of your vehicl e is
impaired , pull ove r as soo n as it is saf e to do so.
Contac t a qualified specialist workshop.
The on-board computer only shows message s or
warning s from certain systems in th e multifunc-
tion display. You should therefor e mak e sur e
your vehicl e is operating safely at all times .
Fo r an overview, see th e instrumen t panel illus-
tration ( Y
page 37).
Displays and operation
Instrument cluster lighting
The lighting in th e instrumen t cluster, in th e dis-
plays and th e control s in th e vehicl e interior can
be adjusted usin g th e brightness control knob.
The brightness control knob is locate d on th e
botto m lef t of th e instrumen t cluste r
( Y
page 37). X
Turn th e brightness control knob clockwise or
counter-clockwise.
If you tur n th e ligh t switch to X , ` or
X , th e brightness is dependen t upon th e
brightness of th e ambien t light.
i The ligh t sensor in th e instrumen t cluste r
automatically control s th e brightness of th e
multifunction display.
In daylight, th e displays in th e instrumen t
cluste r are no t illuminated.
Speedometer with segments The segments in th e speedometer indicat e
whic h spee d range is available. R
Cruis e control activated ( Y
page 174):
The segments ligh t up from th e store d spee d
to th e maximum speed. R
Distanc e Pilot DISTRONI C is activated
( Y
page 176):
On e or two segments in th e set spee d range
ligh t up. R
Distanc e Pilot DISTRONI C detects a vehicl e in
fron t moving mor e slowly than th e store d
speed:
The segments between th e spee d of th e vehi-
cle in fron t and th e store d spee d ligh t up.
Tachometer
! Do no t driv e in th e overrevving range, as this
could damag e th e engine.
The red ban d in th e tachometer indicates th e
engine's overrevving range.
The fuel suppl y is interrupted to protect th e
engin e when th e red ban d is reached.
Outside temperature display You should pay special attention to road condi-
tion s when temperatures are aroun d freezing
point.
Bea r in min d that th e outside temperature dis-
play indicates th e temperature measured and
does no t record th e road temperature.
The outside temperature display is in th e multi-
function display ( Y
page 235).Displays and operation 233
On-board computer and displays 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 ] .X
Visit a qualified specialist workshop .
' (US A only)
M (Canada only)
Check Brake Fluid
Level There is no t enough brak e flui d in th e brak e flui d 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 161).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 .
Active Brake Assist
Functions Currently
Limite d See Opera‐
tor's Manual Active Brake Assis t wit h cross-traffic function is temporarily inopera-
tive.
Possibl e causes are: R
The radar sensor system is temporarily inoperative, e.g. due to
electromagneti c radiation emitted by nearby TV or radi o station s or
other source s of electromagneti c radiation .R
The system is outside th e operating temperature range.R
The 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.
Active Brake Assis t wit h cross-traffic function or PRE ‑ S AF E ®
PLU S is
functional 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 161).X
Restart th e engine.254
Display messages
On-board computer and displays

Warning/
indicator
lamp Q Signal type
Possible causes/consequences and P Solutions
I$
Q I (USA only), $ (Canada only): the red indicator lamp for the electric
parking brake flashes or is lit and/or the yellow warning lamp for the electric
parking brake is lit. X
Observe the additional display messages in the multifunction display.
u
Q The red restraint system warning lamp is lit while the engine is running.
The restraint system is malfunctioning.
G WARNING
The air bags or Emergency Tensioning Devices may either be triggered uninten-
tionally or, in the event of an accident, may not be triggered.
There is an increased risk of injury. X
Observe the additional display messages in the multifunction display. X
Drive on carefully. X
Contact a qualified specialist workshop and have the restraint system checked.
For further information about the restraint system, see ( Y
page 44).Warning and indicator lamps in the instrument cluster 287
On-board computer and displays Z