2017 MERCEDES-BENZ GLS key battery

Problem
Possible causes/consequences and P Solutions
There is interference from a powerful source of radio waves. X
Unlock ( Y
page 81) or lock ( Y
page 81) the vehicle using the
mechanical key.
KEYLESS-GO is malfunctioning. X
Lock/unlock the vehicle using the remote control function of the
SmartKey. X
Have the vehicle and SmartKey checked at a qualified specialist
workshop.
If the vehicle can also not be locked/unlocked using the remote con-
trol function: X
Unlock ( Y
page 81) or lock ( Y
page 81) the vehicle using the
mechanical key. X
Have the vehicle and SmartKey checked at a qualified specialist
workshop.
The engine cannot be
started using the Smart-
Key. The on-board voltage is too low. X
Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work: X
Check the starter battery and charge it if necessary ( Y
page 338).
or X
Jump-start the vehicle ( Y
page 338).
or X
Consult a qualified specialist workshop.
The engine cannot be
started using the Start/
Stop button. The Smart-
Key is in the vehicle. The vehicle is locked. X
Unlock the vehicle and try to start the vehicle again.
The SmartKey battery is discharged or nearly discharged. X
Check the SmartKey battery ( Y
page 77) and replace it if necessary
( Y
page 77).
If this does not work: X
Start your vehicle with the SmartKey in the ignition lock.
There is interference from a powerful source of radio waves. X
Start your vehicle with the SmartKey in the ignition lock.
You have lost a Smart-
Key. X
Have the SmartKey deactivated at a qualified specialist workshop. X
Report the loss immediately to the vehicle insurers. X
If necessary, have the locks changed as well.
You have lost the
mechanical key. X
Report the loss immediately to the vehicle insurers. X
If necessary, have the locks changed as well. SmartKey 79
Opening and closing Z

Driver's and front-passenger seat
Rear seats
The three red indicator lamps in the button indi-
cate the heating level you have selected.
The system automatically switches down from
level 3 to level 2 after approximately eight
minutes.
The system automatically switches down from
level 2 to level 1 after approximately ten
minutes.
The system automatically switches off approx-
imately 35 minutes after it is set to level 1 .X
Turn the SmartKey to position 1 or 2 in the
ignition lock ( Y
page 138).X
To switch on: press button C repeatedly
until the desired heating level is set. X
To switch off: press button C repeatedly
until all the indicator lamps go out. i If the battery voltage is too low, the seat
heating may switch off.
Activating and deactivating seat venti-
lation
The three blue indicator lamps in the buttons
indicate the ventilation level you have selected. X
Turn the SmartKey to position 1 or 2 in the
ignition lock ( Y
page 138). X
To switch on: press button C repeatedly
until the desired ventilation level is set. X
To switch off: press button C repeatedly
until all the indicator lamps go out.
i If the battery voltage is too low, the seat
ventilation may switch off.
i You can open the side windows and the slid-
ing sunroof using the "Convenience opening"
feature ( Y
page 87). The seat ventilation of
the driver's seat automatically switches to the
highest level.104
Seats
Seats, steering wheel an d mirrors

Problems with the seat heating or seat ventilation Problem
Possible causes/consequences and P Solutions
The seat heating or seat
ventilation has switched
off prematurely or can-
not be switched on. The on-board voltage is too low because too many electrical consum-
ers are switched on. X
Switch off electrical consumers that you do not need, such as the
rear window defroster or interior lighting.
Once the battery is sufficiently charged, the seat heating or seat
ventilation will switch back on automatically.
Steering wheel
Important safety notes
G WARNING
You could lose control of your vehicle if you do
the following while driving: R
adjust the driver's seat, head restraint,
steering wheel or mirrors R
fasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirror and fasten your seat belt
before starting the engine.
G WARNING
Children could injure themselves if they
adjust the steering wheel. There is a risk of
injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
The electrically adjustable steering wheel can
still be adjusted when there is no SmartKey in
the ignition lock.
Adjusting the steering wheel man-
ually
G WARNING
If the steering wheel is unlocked while the
vehicle is in motion, it could change position
unexpectedly. This could cause you to lose control of the vehicle. There is a risk of an
accident.
Before starting off, make sure the steering
wheel is locked. Never unlock the steering
wheel while the vehicle is in motion.
C
Release lever D
Adjusts the steering wheel height

The daytime running lamps improve the visibility
of your vehicle during the day. To do this, the
daytime running lamps function must be
switched on using the on-board computer
( Y
page 239).
If the engine is running and you turn the light
switch to ` or X , the manual settings
take precedence over the daytime running
lamps.
Low-beam headlamps Even if the light sensor does not detect that it is
dark, the parking lamps and low-beam head-
lamps switch on when the ignition is switched on
and the light switch is set to the X position.
This is a particularly useful function in the event
of rain and fog. X
To switch on the low-beam headlamps:
turn the SmartKey in the ignition lock to posi-
tion 2 or start the engine.X
Turn the light switch to X .
The green X indicator lamp in the instru-
ment cluster lights up.
Rear fog lamp The rear fog lamp improves visibility of your
vehicle for the traffic behind in the event of thick
fog. Please take note of the country-specific
regulations for the use of rear fog lamps. X
To switch on the rear fog lamp: turn the
SmartKey in the ignition lock to position 2 or
start the engine. X
Turn the light switch to X or q .X
Press the ^ button.
The yellow ^ indicator lamp in the instru-
ment cluster lights up. X
To switch off the rear fog lamp: press the
^ button.
The yellow ^ indicator lamp in the instru-
ment cluster goes out.
Parking lamps
! If the battery charge is very low, the parking
lamps or standing lamps are automatically
switched off to enable the next engine start.
Always park your vehicle safely and in a well lit
area, in accordance with the relevant legal
stipulations. Avoid using the ` parking
lamps over a period of several hours. If pos-
sible, switch on the right-hand d or left-
hand c standing lamps. X
To switch on: turn the light switch to ` .
The green ` indicator lamp in the instru-
ment cluster lights up.
Standing lamps Switching on the standing lamps ensures the
corresponding side of t he vehicle is illuminated.X
To switch on the standing lamps: the
SmartKey should not be in the ignition lock or
it should be in position 0 .X
Turn the light switch to c (left-hand side of
the vehicle) or d (right-hand side of the
vehicle).
Vehicles towing a trailer: both the right-hand
and left-hand standing lamps (tail lamps) are
always illuminated on the trailer.
Combination switch
C
High-beam headlamps D
Turn signal, right

Rear overhead control panel (thir d row of seats)
C
Readin g lamp
Interior lighting control
General notes In order to prevent the veh icle 's battery fr om
disc harg ing , the int erior lighting funct ion s are
automatical ly deactivated after some time
except when the Sm artKey is in posi tion 2 in the
igniti on loc k.
The co lor and brightne ss for the ambient lighting
may be set via the multimedia system (see the
separate oper ati ng ins truct ion s).
Automatic interior lighting control X
To switch on: set the swit ch to center posi -
tion

i If you clean the windows regularly, they do
not fog up so quickly.
Rear window defroster
General notes The rear window defroster has a high current
draw. You should therefore switch it off as soon
as the rear window is clear. Otherwise, the rear
window defroster switches off automatically
after several minutes. If the battery voltage is too low, the rear window
defroster may switch off.
Switching on/off X
Turn the SmartKey to position 2 in the ignition
lock ( Y
page 138). X
Press the l button.
The indicator lamp in the l button lights
up or goes out.
Problems with the rear window defroster Problem
Possible causes/consequences and P Solutions
The rear window
defroster has deactiva-
ted prematurely or can-
not be activated. The battery has not been sufficiently charged. X
Switch off any consumers that are not required, e.g. reading lamps,
interior lighting or the seat heating.
When the battery is sufficiently charged, the rear window defroster
can be activated again.
Switching air-recirculation mode
on/off
General notes You can deactivate the flow of fresh air if
unpleasant odors are entering the vehicle from
outside. The air already inside the vehicle will
then be recirculated.
If you switch on air-recirculation mode, the win-
dows can fog up more quickly, in particular at
low temperatures. Only use air-recirculation
mode briefly to prevent the windows from fog-
ging up.
Switching on/off X
Turn the SmartKey to position 2 in the ignition
lock ( Y
page 138).X
To activate: press the

ignite if in contact with the exhaust system or
parts of the engine that heat up. There is a risk
of fire.
Carry out regular checks to make sure that
there are no flammable foreign materials in
the engine compartment or in the exhaust
system.
General notes Vehicles with a gasoline engine: the catalytic
converter is preheated for up to 30 seconds
after a cold start. The sound of the engine may
change during this time.
Automatic transmission X
Shift the transmission to position P
( Y
page 146).
The transmission position display in the mul-
tifunction display shows P ( Y
page 148).
i You can start the engine in transmission
position P and N .
Starting procedure with the SmartKey X
To start a diesel engine : turn the SmartKey
to position 2 in the ignition lock ( Y
page 138).
The \( preglow indicator lamp in the instru-
ment cluster lights up. X
Turn the SmartKey to position 3 in the ignition
lock and release it as soon as the engine is
running ( Y
page 138).
i Vehicles with a diesel engine: you can
start the engine without preglow if the engine
is warm.
Using KEYLESS-GO to start the engine The Start/Stop button can be used to start the
vehicle without inserting the SmartKey into the
ignition lock. The Start/Stop button must be
inserted in the ignition lock and the SmartKey
must be in the vehicle. This mode for starting the
engine operates independently of the ECO
start/stop automatic engine start function. X
Depress the brake pedal and keep it
depressed. X
Press the Start/Stop button once
( Y
page 138).
Vehicles with a gasoline engine: the engine
starts.
Vehicles with a diesel engine: preglow is
activated and the engine starts.
Starting procedure via smartphone Observe the important safety notes on starting
the engine ( Y
page 139).
You can also start your engine via your smart-
phone from outside the vehicle. In this case, the
previously selected climate control setting is
activated. In this way you can cool or heat the
interior of the vehicle before starting the jour-
ney.
Only start the engine via your smartphone if it is
safe to start and run the engine where your vehi-
cle is parked.
Observe the legal stipulations in the area where
your vehicle is parked. Engine start via smart-
phone may be limited to certain countries or
regions.
You can execute a maximum of two consecutive
starting attempts via your smartphone. If you
insert the SmartKey into the ignition lock, you
can carry out two more starting attempts.
Once you have started the engine, you can
switch the engine off via your smartphone at any
time.
You can only start the engine via your smart-
phone if: R
the SmartKey is in the ignition lock R
park position P is selected R
the accelerator pedal is not depressed R
the anti-theft alarm system is not activated R
the panic alarm is not activated R
the hazard warning lamps are switched off R
the hood is closed. R
the doors are closed and locked R
the windows and sliding sunroof are closed
Also make sure that: R
the fuel tank is sufficiently filled R
the starter battery is sufficiently charged140
Driving
Driving and parking

If indicator lamp D is off, the ECO start/stop
function has been deactivated manually or as
the result of a malfunction.
Problems with the engine Problem
Possible causes/consequences and P Solutions
The engine does not
start. The starter motor
can be heard. R
There is a malfunction in the engine electronics. R
There is a malfunction in the fuel supply.
Before attempting to start the engine again: X
Turn the SmartKey back to position 0 in the ignition lock.
or X
Press the Start/Stop button repeatedly until all indicator lamps in
the instrument cluster go out. X
Try to start the engine again ( Y
page 139). Avoid excessively long
and frequent attempts to start the engine as these will drain the
battery.
If the engine does not start after several attempts: X
Consult a qualified specialist workshop.
The engine does not
start. You cannot hear
the starter motor. The on-board voltage is too low because the battery is too weak or
discharged. X
Jump-start the vehicle ( Y
page 338).
If the engine does not start despite attempts to jump-start it: X
Consult a qualified specialist workshop.
The starter motor was exposed to a thermal load that was too high. X
Allow the starter motor to cool down for approximately two minutes. X
Try to start the engine again.
If the engine still does not start: X
Consult a qualified specialist workshop.144
Driving
Driving and parking