2017 MERCEDES-BENZ GLS-Class SUV ECU

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:
Rin your place of residence
Rin the location to which you are driving
The police and local authorities can provide reli- able information.
Observe the following when towing a trailer:
RTo 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
RBefore driving, check:
-trailer tow hitch
-safety switch for braked trailers
-safety chains
-electrical connections
-lights
-wheels
RAdjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer.
RIf the trailer has electronically controlled
brakes, pull away carefully. Brake manually
using the brake controller and check whether
the brakes function correctly.
RSecure any objects on the trailer to prevent
the cargo from slipping when the vehicle is in
motion.
RWhen you couple up a trailer, check at regular
intervals that the load is firmly secured. If the
tra
iler is equipped with trailer lights and
brakes, check the trailer to ensure that these
are working.
RBear in mind that the handling will be less
stable when towing a trailer than when driving
without one. Avoid sudden steering move-
ments.
RThe 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.
RIf 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.
RIf 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.
RWhen driving downhill, shift to a lower gear toutilize the engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if instal-
led, the trailer brakes.
RIf the coolant temperature increases dramat-
ically while the air-conditioning 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.
RWhen 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.
Decoupling a trailer
GWARNING
If you uncouple a trailer with the overrun
brake engaged, you could trap your hand
between the vehicle and the trailer drawbar.
There is a risk of injury.
Do not uncouple a trailer if the overrun brake
is engaged.
GWARNING
Vehicles with level control:
The vehicle is lowered as soon as you discon-
nect the trailer cable. This could result in your
limbs or those of other people that are
between the vehicle body and tires or under-
226Towing a trailer
Driving an d parking

Display messagesPossible causes/consequences andMSolutions
The yellow!warning lamp and th ered F (USAonly) or !
(Canada only) indicator lamp ligh tup.
The electric parking brak eis malfunctioning .
To release:
XSwitc hoff th eignition and tur nit bac kon .
XReleas eth eelectric parking brak emanually.
or
XReleas eth eelectric parking brak eautomatically (Ypage 160).
If th eelectric parking brak estill canno tbe released:
XDo no tdrive on .
XConsult aqualified specialist workshop .
The redF(USAonly) or !(Canada only) indicator lamp flashes
and th eyellow !warning lamp lights up.
The electric parking brak eis malfunctioning .
To release:
XSwitc hoff th eignition and tur nit bac kon .
XReleas eth eelectric parking brak emanually.
To apply :
XSwitchoff th eignition and tur nit bac kon .
XApply th eelectric parking brak emanually.
If th ered F (USAonly) or !(Canada only) indicator lamp con-
tinue sto flash:
XDo no tdrive on .
XSecureth evehicl eagainst rollin gaway (Ypage 367).
XShift th etransmission to position P.
XTurn thefron twheels toward sth ecurb.
XConsult aqualified specialist workshop .
248Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
The yellow!warning lamp lights up and th ered F (USAonly)
or ! (Canada only) indicator lamp flashes .
It is no tpossibl eto apply th eelectric parking brak emanually.
XShift th etransmission to position P.
XVisitaqualified specialist workshop .
$(USA
only)
J( Canada
only)
Check Brake Fluid
Level
There is no tenough brak eflui din th ebrak eflui dreservoir .In addition ,
th e$ (USAonly) or J(Canada only) warning lamp lights up in
th einstrumen tcluste rand awarning tone sounds.
GWARNIN G
The braking effec tmay be impaired.
There is aris kof an accident.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions. Do no tcontinu edrivin g
under any circumstances.
XSecur eth evehicl eagainst rollin gaway (Ypage 159).
XConsult aqualified specialist workshop .
XDo notadd brak efluid .This does no tcorrec tth emalfunction .
#
CheckBrakePadWear
The brak epads/linings hav ereached their wear limit.
US Aonly: th e$ red brak esystem warning lamp is lit while th e
engin eis running.
XVisit aqualified specialist workshop .
G
Inoperative
Oneor mor emain features of th embrace system are malfunctioning .
XVisitaqualified specialist workshop .
ActiveBrakeAssistFunctionsCurrentlyLimitedSee Opera‐tor's Manual
Active Brake Assis twit hcross-traffic function is temporarily inopera-
tive.
Possibl ecauses are:
Rth eradar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation
Rth esystem is outside th eoperating temperature range
Rth eon-boar dvoltag eis to olow.
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
Active Brake Assis twit hcross-traffic function or PRE ‑S AF E
®PLU Sis
functional again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 159).
XRestart th eengine.
250Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
ActiveBrakeAssistFunctions LimitedSee Operator'sMan ‐ual
Active Brake Assis tis unavailable due to amalfunction .Adaptive
Brake Assis tmay also hav efailed.
XVisit aqualified specialist workshop immediately.
PRE-SAFE Inopera‐tiv eSeeOperator' sManual
Importantfunction sof PRE-SAF E®havefailed. Al lother occupant
safet ysystems ,e.g. air bags ,remain available.
XVisit aqualified specialist workshop immediately.
ActiveBrakeAssistFunctionsCurrentlyLimite dSee Opera‐tor's Manual
Active Brake Assis tor PRE‑ SAFE®PLUSis temporarily inoperative.
Possibl ecauses are:
Rfunction is impaire ddue to heav yrain or snow
Rth eradar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation
RMercedes-AMG vehicles: ES P®is deactivated
Rthesystem is outside th eoperating temperature range
Rth eon-boar dvoltag eis to olow.
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
Active Brake Assis tor PRE‑ SAFE
®PLUSis operative again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 159).
XRestart th eengine.
XMercedes-AMG vehicles: switch ES P®on again(Ypage 67).
ActiveBrakeAssistFunctions Limite dSee Operator'sMan ‐ual
Active Brake Assis twit hcross-traffic function or PRE ‑S AF E®PLU Sis
no tavailable due to amalfunction .
XVisitaqualified specialist workshop immediately.
Display messages25 1
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
RadarSensorsDirtySee Operator' sMan ‐ual
The radar sensor system is malfunctioning .
Possibl ecauses are:
RDirt on sensor s
RHeavy rain or snow
RWhendrivin gon inter-urban roads without traffic or infrastructure,
e.g. in desert-like area s
At least on edrivin gsystem or drivin gsafet ysystem is malfunctioning
or is temporarily unavailable :
RPRE-SAFE®PLUS
RActive Brake Assis t
RActive LaneKeepin gAssis t
RActive Blind Spot Assis t
RDistancePilo tDISTRONI C
If th eradar sensor system in fron tis dirty, Active Blind Spot Assis twill
no tperfor m acourse-correcting brak eapplication .
A warning tone also sounds.
Once th ecaus eof th eproblem is no longer present, th edrivin gand
drive safet ysystems will be available again .The display message dis-
appears.
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 159).
XSwitchoff th eengine.
XClean all sensor s (Ypage 328).
XRestart theengine.
The display message disappears.
6
SRSMalfunctionSer ‐viceRequired
The restrain tsystem is malfunctioning .
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
Fo rfurther information about th erestrain tsystem, see (
Ypage 41).
6
Front Lef tMalfunc‐tio nServic eRequiredorFron tRight MalfunctionServic eRequired
The restrain tsystem has malfunctioned at th efron ton th elef tor right .
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
252Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
6
RearLef tMalfunc‐tio nServic eRequiredorRea rRight MalfunctionServic eRequired
The restrain tsystem has malfunctioned at th erear on th elef tor right .
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
6
Rea rCenterMalfunc‐tionServic eRequired
The restrain tsystem has malfunctioned at th erear center. The 6
warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
6
Lef tSid eCurtai nAirbag MalfunctionServiceRequiredorRigh tSideCurtai nAirbagMalfunctionServiceRequired
The left-han dor right-hand window curtai nair bag is malfunctioning .
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The lef tor right window curtai nair bag may either be triggered unin-
tentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
Display messages25 3
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
FrontPassengerAir‐bag Disabled SeeOperator' sManual
The front-passenger fron tair bag is deactivated during th ejourney,
eve nthough :
Ran adult
or
Raperson of th ecorrespondin gstatur eis on th efront-passenger seat
If additional force sare applie dto th eseat ,th esystem may interpret
th eoccupant's weigh tas lower than it actually is.
GWARNIN G
The front-passenger air bag does no tdeploy during an accident.
There is an increased ris kof injury.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 159).
XSwitchth eignition off .
XHaveth eoccupant get out of th evehicle.
XKee pth eseat unoccupied ,close th efront-passenger door and
switch on th eignition .
XObserveth ePASSENGER AI RBA Gindicator lamp sin th ecenter
console and th emultifunction display and chec kth efollowing:
Seat unoccupied and ignition switched on :
Raself-diagnosis is carrie dout .The PASSENGER AI RBA GOF Fand
PASSENGER AI RBA GON indicator lamp smus tligh tup simulta-
neousl yfor approximately six seconds
Rth ePASSENGER AI RBA GOF Findicator lamp mus tthen ligh tup
and remain lit after theself-diagnosis .If th eindicator lamp is on ,
OCS (Occupant Classification System) has disabled th efront-
passenger fron tair bag (
Ypage 49 )
RtheFront Passenger Airbag Enable dSee Operator' sManualorFront Passenger Airbag Disabled See Opera‐tor's Manualdisplay message smus tno tbe shown in th emul-
tifunction display
XWait for aperiod of at least 60 seconds until th enecessar ysystem
checks hav ebeen completed.
XMak esur ethat th edisplay message sdo no tappear in th emulti-
function display.
If these condition sare fulfilled ,th efront-passenger seat can be occu-
pied again .Whether th ePASSENGER AI RBA GOF For ON indicator
lamp remain slit or goe sout depend son how OCS classifies th eoccu-
pant.
If th econdition sare no tfulfilled ,th esystem is no toperating correctly.
XVisit aqualified specialist workshop immediately.
Fo rfurther information about th eOccupant Classification System, see
(
Ypage 49) .
254Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
FrontPassengerAir‐bag Enable dSeeOperator' sManual
The front-passenger fron tair bag is enabled during th ejourney, eve n
though :
Rachild, asmall adult or an objec tweighing less than th esystem' s
weigh tthreshold is locate don th efront-passenger seat
or
Rth efront-passenger seat is unoccupied
The system may detec tobjects or force sapplyin gadditional weigh ton
th eseat .
GWARNIN G
The front-passenger fron tair bag may deploy unintentionally.
There is an increased ris kof injury.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 159).
XSwitchth eignition off .
XOpenth efront-passenger door .
XRemove thechild and th echild restrain tsystem from th efront-
passenger seat .
XMakesur ethat there are no objects on th eseat addin gto th e
weight.
The system may otherwise detec tth eadditional weigh tand inter-
pre tth eseat occupant's weigh tas greate rthan it actually is.
XKee pth eseat unoccupied ,close th efront-passenger door and
switch on th eignition .
XObserveth ePASSENGER AI RBA Gindicator lamp sin th ecenter
console and th emultifunction display and chec kth efollowing:
Seat unoccupied and ignition switched on :
Raself-diagnosis is carrie dout .The PASSENGER AI RBA GOF Fand
PASSENGER AI RBA GON indicator lamp smus tligh tup simulta-
neousl yfor approximately six seconds
Rth ePASSENGER AI RBA GOF Findicator lamp mus tthen ligh tup
and remain lit after th eself-diagnosis .If th eindicator lamp is on ,
OCS has disabled th efront-passenger fron tair bag (
Ypage 49)
RtheFront Passenger Airbag Enable dSee Operator' sManualorFront Passenger Airbag Disabled See Opera‐tor's Manualdisplay message smus tno tbe shown in th emul-
tifunction display
XWait for aperiod of at least 60 seconds until th enecessar ysystem
checks hav ebeen completed.
XMak esur ethat th edisplay message sdo no tappear in th emulti-
function display.
If these condition sare fulfilled ,th efront-passenger seat can be occu-
pied again .Whether th ePASSENGER AI RBA GOF For ON indicator
lamp remain slit or goe sout depend son how OCS classifies th eoccu-
pant.
If th econdition sare no tfulfilled ,th esystem is no toperating correctly.
Display messages25 5
On-board computer and displays
Z