ECU MERCEDES-BENZ CLS 2018 Owner's Manual

Problem
Possible causes/consequences and P Solutions
The SmartKey battery is discharged or nearly discharged. X
Unlock the vehicle using the mechanical key ( Y
page 78).X
Open the trunk lid. X
Manually unlock the fuel filler flap using the emergency release
( Y
page 140).
The fuel filler flap is unlocked, but the opening mechanism is jammed. X
Consult a qualified specialist workshop.
Parking
Important safety notes
G WARNING
Flammable material such as leaves, grass or
twigs may ignite if they come into contact with
hot parts of the exhaust system or exhaust
gas flow. There is a risk of fire.
Park the vehicle so that no flammable mate-
rials come into contact with parts of the vehi-
cle which are hot. Take particular care not to
park on dry grassland or harvested grain
fields.
G WARNING
If you leave children unsupervised in the vehi-
cle, they could set it in motion by, for example: R
release the parking brake. R
shift the automatic transmission out of the
parking position P .R
start the engine.
In addition, they may operate vehicle equip-
ment and become trapped. There is a risk of
an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
! Always secure the vehicle correctly against
rolling away. Otherwise, the vehicle or its driv-
etrain could be damaged. To ensure that the vehicle is secured against
rolling away unintentionally: R
the parking brake must be applied. R
the transmission must be in position P and the
Smartkey must be removed from the ignition
lock. R
the front wheels must be turned towards the
curb on steep uphill or downhill gradients.
Switching off the engine
Important safety notes
G WARNING
The automatic transmission switches to neu-
tral position N when you switch off the engine.
The vehicle may roll away. There is a risk of an
accident.
After switching off the engine, always switch
to parking position P . Prevent the parked vehi-
cle from rolling away by applying the parking
brake.
Vehicles with automatic transmission X
Apply the parking brake firmly. X
All vehicles (except Mercedes-AMG vehi-
cles): shift the transmission to position P .Parking 141
Driving and parking Z

between your vehicle and the vehicle in front
becomes too small.
i When you change lanes, DISTRONIC PLUS
monitors the left lane on left-hand-drive vehi-
cles or the right lane on right-hand-drive vehi-
cles.
Stopping
G WARNING
When leaving the vehicle, even if it is braked
only by DISTRONIC PLUS, it could roll away if: R
there is a malfunction in the system or in
the voltage supply. R
DISTRONIC PLUS has been deactivated
with the cruise control lever, e.g. by a vehi-
cle occupant or from outside the vehicle. R
the electrical system in the engine com-
partment, the battery or the fuses have
been tampered with. R
the battery is disconnected. R
the accelerator pedal has been depressed,
e.g. by a vehicle occupant.
There is a risk of an accident.
If you wish to exit the vehicle, always turn off
DISTRONIC PLUS and secure the vehicle
against rolling away.
For further information on deactivating
DISTRONIC PLUS ( Y
page 155).
If DISTRONIC PLUS detects that the vehicle in
front has stopped, it will cause your vehicle to
brake and come to a halt.
Once your vehicle is stationary, it remains sta-
tionary and you do not need to depress the
brake.
Depending on the specified minimum distance,
your vehicle will come to a standstill at a suffi-
cient distance behind the vehicle in front. The
specified minimum distance is set using the
control on the cruise control lever.
When DISTRONIC PLUS is activated, the trans-
mission is shifted automatically to position P if:R
the driver's door is open and the driver's seat
belt is unfastened. R
the engine is switched off, unless it is auto-
matically switched off by the ECO start/stop
function. R
a system malfunction occurs. R
the power supply is not sufficient.
Setting a speed X
Press the cruise control lever up C for a
higher speed or down D for a lower speed.X
To adjust the set speed in 1 mph incre-
ments (1 km/h increments): briefly move
the cruise control lever up C or down D to
the pressure point.
Every time the cruise control lever is pressed
up C or down D , the last speed stored is
increased or reduced. X
To adjust the set speed in 5 mph incre-
ments (1 0 km/h increments): briefly move
the cruise control lever up C or down D
beyond the pressure point.
Every time the cruise control lever is pressed
up C or down D , the last speed stored is
increased or reduced.
i If you accelerate to overtake, DISTRONIC
PLUS adjusts the vehicle's speed to the last
speed stored after you have finished overtak-
ing.
Setting a specified minimum distance You can set the specified minimum distance for
DISTRONIC PLUS by varying the time span
between one and two seconds. With this func-
tion, you can set the minimum distance that
DISTRONIC PLUS keeps to the vehicle in front,
dependent on vehicle speed. You can see this
distance in the multifunction display
( Y
page 154).
i Make sure that you maintain a sufficient
distance to the vehicle in front and comply
with the minimum distance as required by
law. Adjust the distance to the vehicle in front
if necessary.Driving systems 153
Driving and parking Z

still not started to steer and have not taken hold
of the steering wheel after five seconds at the
latest, a warning tone also sounds to remind you
to take control of the vehicle. Steering Assist
and Stop&Go Pilot are switched to passive.
DISTRONIC PLUS remains active.
Activating Steering Assist and Stop&Go
Pilot X
Activate the DISTRONIC PLUS with Steering
Assist and Stop&Go Pilot function using the
on-board computer ( Y
page 196).
The DTR+: Steering Assistant On mes-
sage appears in the multifunction display.
Steering Assist and Stop&Go Pilot are active.
Information in the multifunction display
If Steering Assist and Stop&Go Pilot are activa-
ted but not ready for a steering intervention,
steering wheel symbol C appears in gray. If the
system provides you with support by means of
steering interventions, symbol C is shown in
green.
Deactivating Steering Assist and Stop&Go
Pilot X
Deactivate the DISTRONIC PLUS with Steer-
ing Assist and Stop&Go Pilot function using
the on-board computer ( Y
page 196).
The DTR+: Steering Assistant Off mes-
sage appears in the multifunction display.
Steering Assist and Stop&Go Pilot are deac-
tivated.
When DISTRONIC PLUS is deactivated or not
available, Steering Assist and Stop&Go Pilot are
deactivated automatically. HOLD function
General notes The HOLD function can assist the driver in the
following situations: R
when pulling away, especially on steep slopes R
when maneuvering on steep slopes R
when waiting in traffic
The vehicle is kept stationary without the driver
having to depress the brake pedal.
The braking effect is canceled and the HOLD
function deactivated when you depress the
accelerator pedal to pull away.
Important safety notes
G WARNING
When leaving the vehicle, it can still roll away
despite being braked by the HOLD function if: R
there is a malfunction in the system or in
the voltage supply. R
the HOLD function has been deactivated by
pressing the accelerator pedal or the brake
pedal, e.g. by a vehicle occupant. R
the electrical system in the engine com-
partment, the battery or the fuses have
been tampered with. R
the battery is disconnected
There is a risk of an accident.
If you wish to exit the vehicle, always turn off
the HOLD function and secure the vehicle
against rolling away.
! When DISTRONIC PLUS or the HOLD func-
tion is activated, the vehicle brakes automat-
ically in certain situations.
To avoid damage to the vehicle, deactivate
DISTRONIC PLUS and the HOLD function in
the following or similar situations: R
when towing the vehicle R
in the car washDriving systems 157
Driving and parking Z

Display messages
Possible causes/consequences and P Solutions
' (US A only)
M (Canada only)
Check Brake Fluid
Level There is no t enough brak e fluid 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 141).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.X
Visit a qualified specialist workshop .
S mbrace 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 141).X
Restart th e engine.
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 .
PRE-SAFE
Inoperative 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 .206
Display messages
On-board computer and displays

Display messages
Possible causes/consequences and P Solutions
PRE-SAFE
Functions Currently
Limite d See Opera‐
tor's Manual 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
Mercedes-AMG vehicles: ES P ®
is deactivatedR
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.
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 141).X
Restart th e engine.X
Mercedes-AMG vehicles: switch ES P ®
on again ( Y
page 71).
PRE-SAFE
Functions Limite d
See Operator' s Man ‐
ual 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 .Display messages 20 7
On-board computer and displays Z

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
COLLISION PREVENTION ASSIST PLU SR
PRE-SAF E ®
BrakeR
PRE-SAF E ®
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 .
A warning tone also sounds.
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 141).X
Switc h off th e engine.X
Clean all sensor s ( Y
page 274).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.
Observ e th e additional information on restrain t systems ( Y
page 41).208
Display messages
On-board computer and displays

Display messages
Possible causes/consequences and P Solutions
Front Passenger Air ‐
bag Disabled
See Operator' s Man ‐
ual The front-passenger fron t air bag and front-passenger knee bag are
deactivated during th e journey, although:R
an adult
or R
a person of th e correspondin g statur e is on th e front-passenger seat
If additional force s are applie d to th e seat , th e system may interpret
th e occupant's weigh t as lower than it actually is.
G WARNIN G
The front-passenger fron t air bag and front-passenger knee bag does
no t deploy in th e event of an accident.
There is an increased ris k of injury.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 141).X
Switc h th e ignition off .X
Hav e th e occupant get out of th e vehicle.X
Kee p th e seat unoccupied , close th e front-passenger door and
switch on th e ignition .X
Observ e th e PASSENGER AI R BA G OF F indicator lamp in th e center
console and th e multifunction display and chec k th e following:
Seat unoccupied and ignition switched on :R
a self-diagnosis is carrie d out . The PASSENGER AI R BA G OF F and
PASSENGER AI R BA G ON indicator lamp s mus t ligh t up simulta-
neousl y for approximately six seconds R
th e PASSENGER AI R BA G O F F indicator lamp mus t then ligh t up
and remain lit after th e self-diagnosis . If th e indicator lamp is on ,
th e OCS (Occupant Classification System) has disabled th e front-
passenger fron t air bag and front-passenger knee bag
( Y
page 49) R
th e Front Passenger Airbag Enable d See Operator' s
Manual or Front Passenger Airbag Disabled See Opera‐
tor's Manual display message s mus t no t be shown in th e mul-
tifunction display X
Wait for a period of at least 60 seconds until th e necessar y system
checks hav e been completed.X
Mak e sur e that th e display message s do no t appear in th e multi-
function display.
If these condition s are fulfilled , th e front-passenger seat can be occu-
pied again . Whether th e PASSENGER AI R BA G OF F indicator lamp
remain s lit or goe s out depend s on how OCS classifies th e occupant .
If th e condition s are no t fulfilled , th e system is no t operating correctly.X
Visit a qualified specialist workshop immediately.
Observ e th e additional information on OCS ( Y
page 49).
Front Passenger Air ‐
bag Enable d The front-passenger fron t air bag and front-passenger knee bag are
enabled during th e journey, although:210
Display messages
On-board computer and displays

Display messages
Possible causes/consequences and P Solutions
See Operator' s Man ‐
ual R
a child, a small adult or an objec t weighing less than th e system' s
weigh t threshold is locate d on th e front-passenger seat
or R
th e front-passenger seat is unoccupied
The system may detec t objects or force s applyin g additional weigh t on
th e seat .
G WARNIN G
The front-passenger fron t air bag and front-passenger knee bag may
deploy unintentionally.
There is an increased ris k of injury.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 141).X
Switc h th e ignition off .X
Ope n th e front-passenger door .X
Remove th e child and th e child restrain t system from th e front-
passenger seat .X
Mak e sur e that there are no objects on th e seat addin g to th e
weight.
The system may otherwise detec t th e additional weigh t and inter-
pre t th e seat occupant's weigh t as greate r than it actually is.X
Kee p th e seat unoccupied , close th e front-passenger door and
switch on th e ignition .X
Observ e th e PASSENGER AI R BA G OF F indicator lamp in th e center
console and th e multifunction display and chec k th e following:
Seat unoccupied and ignition switched on :R
a self-diagnosis is carrie d out . The PASSENGER AI R BA G OF F and
PASSENGER AI R BA G ON indicator lamp s mus t ligh t up simultane -
ousl y for approximately six seconds R
th e PASSENGER AI R BA G OF F indicator lamp mus t then ligh t up and
remain lit after th e self-diagnosis . If th e indicator lamp is on , th e
OCS has disabled th e front-passenger fron t air bag and front-
passenger knee bag ( Y
page 49 )R
th e Front Passenger Airbag Enable d See Operator' s Man ‐
ual or Front Passenger Airbag Disabled See Operator' s
Manual display message s mus t no t be shown in th e multifunction
display X
Wait for a period of at least 60 seconds until th e necessar y system
checks hav e been completed.X
Mak e sur e that th e display message s do no t appear in th e multi-
function display.
If these condition s are fulfilled , th e front-passenger seat can be occu-
pied again . Whether th e PASSENGER AI R BA G OF F indicator lamp
remain s lit or goe s out depend s on how OCS classifies th e occupant .
If th e condition s are no t fulfilled , th e system is no t operating correctly.X
Visit a qualified specialist workshop immediately.
Observ e th e additional information on OCS ( Y
page 49).Display messages 21 1
On-board computer and displays Z

Display messages
Possible causes/consequences and P Solutions
= See Operator' s Man ‐
ual The battery is no t bein g charged.
A warning tone also sounds.
Possibl e causes are: R
a defective alternato rR
a torn poly-V-belt R
a malfunction in th e electronics
! Do no t continu e driving. The engin e could otherwise overheat.X
Pull ove r and stop th e vehicl e safely and switch off th e engine, pay-
ing attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 141).X
Consult a qualified specialist workshop .
= Sto p Vehicl e See
Operator' s Manual The battery is no longer bein g charged and th e battery charg e level is
to o low.
A warning tone also sounds. X
Pull ove r and stop th e vehicl e safely and switch off th e engine, pay-
ing attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 141).X
Observ e th e instruction s in th e = See Operator' s Manual
display message .X
Consult a qualified specialist workshop .

Display messages
Possible causes/consequences and P Solutions
Lan e Keepin g Assist
Currently Unavaila‐
ble See Operator' s
Manual or Active
Lan e Keepin g Assist
Currently Unavaila‐
ble See Operator' s
Manual Lan e Keepin g Assis t or Active Lan e Keepin g Assis t is deactivated and
temporarily inoperative.
Possibl e causes are: R
th e windshield in th e camera' s field of vision is dirtyR
visibilit y is impaire d due to heav y rain , snow or fogR
there hav e been no lan e marking s for an extended periodR
th e lan e marking s are worn, dark or covered, e.g. by dir t or snow
Whe n th e causes state d abov e no longer apply, th e display message
disappears.
Lan e Keepin g Assis t or Active Lan e Keepin g Assis t 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 141).X
Clean th e windshield.
Lan e Keepin g Assist
Inoperative or
Active Lan e Keepin g
Assist Inoperative Lan e Keepin g Assis t or Active Lan e Keepin g Assis t is malfunctioning .X
Visit a qualified specialist workshop .
Blind Spo t Assist
Currently Unavaila‐
ble See Operator' s
Manual or Active
Blind Spo t Assist
Currently Unavaila‐
ble See Operator' s
Manual Blind Spot Assis t or Active Blind Spot Assis t is temporarily inoperative.
Possibl e causes are: R
th e radar sensor system is outside th e operating temperature rangeR
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
The yellow c indicator lamp s also ligh t up in th e exterio r mirrors.
Whe n th e causes state d abov e no longer apply, th e display message
disappears.
Blind Spot Assis t or Active Blind Spot Assis t 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 141).X
Restart th e engine.
Blind Spo t Assist
Inoperative or
Active Blind Spo t
Assist Inoperative Blind Spot Assis t or Active Blind Spot Assis t is malfunctioning .
The yellow c indicator lamp s also ligh t up in th e exterio r mirrors.X
Visit a qualified specialist workshop .
Par k Assist Canceled The driver's door is open and th e driver's seat belt has no t been fas -
tened. X
Repeat th e parking process wit h th e seat belt fastene d and th e
driver's door closed .Display messages 21 7
On-board computer and displays Z