Get Driving and parking -> Towing a trailer Guide for Mercedes A Class 4 Door Third Generation (2012-2017)

Driving systems

226

End of a speed limit

Important safety notes

WARNING

No speed limit : applies here.

G

Blind Spot Assist does not react to vehicles:

R

overtaken too closely on the side, placing

them in the blind spot area

R

when the difference in the speed of

approach and overtaking is too great

As a result, Blind Spot Assist cannot warn

drivers in these situations. There is a risk of an

accident.

Always pay careful attention to the traffic sit-

uation and maintaina safedistance at the side

of the vehicle.

No entry (wrong-way warning)

A warning message : is displayed in the

instrument cluster if Traffic Sign Assist

detects that you are passing a “no entry” sign

and you are driving in the wrong direction.

You will then also hear a warning tone. You

should immediately check your direction of

travel in order to avoid danger to yourself and

other road users.

Blind Spot Assist is only an aid. It may fail to

detect some vehicles and is no substitute for

attentive driving. Always ensure that there is

sufficient distance to the side for other road

users and obstacles.

Radar sensors

The radar sensors for Blind Spot Assist are

integrated into the rear bumper. Make sure

that the bumpers are free from dirt, ice or

slush. The sensors must not be covered, for

example by cycle racks or overhanging loads.

Following a severe impact or in the event of

damage to the bumpers, have the function of

the radar sensors checked at a qualified spe-

cialist workshop. Blind Spot Assist may no

longer work properly.

Lane Tracking package

General notes

The Lane Tracking package consists of Blind

Spot Assist (Y page 226) and Lane Keeping

Assist (Y page 228).

Blind Spot Assist

General notes

Monitoring range of the sensors

In particular, the detection of obstacles can

be impaired in the case of:

Blind Spot Assist monitors the areas on either

side of the vehicle that are not visible to the

driver with two lateral, rear-facing radar sen-

sors. A warning display in the exterior mirrors

draws your attention to vehicles detected in

the monitored area. If you then switch on the

corresponding turn signal to change lanes,

you will also receive a visual and audible col-

lision warning.

R

dirt on the sensors or obscured sensors

R

poor visibility, e.g. due to fog, heavy rain or

snow

R

a narrow vehicle travelling in front, e.g. a

motorcycle or a bicycle

R

very wide lanes

R

narrow lanes

vehicles not driving in the middle of their

lane

Blind Spot Assist supports you from a speed

of approximately 30 km/h.

R

barriers or other road boundaries

Driving systems

227

Warning display

Vehicles in the monitoring range are then not

indicated.

:

Warning display

Blind Spot Assist is not active at speeds below

approximately 30 km/h. Vehicles in the mon-

itoring range are then not indicated.

If Blind Spot Assist is activated, indicator

lamp : in the exterior mirrors lights up yel-

low up to a speed of 30 km/h. At speeds

above 30 km/h, the indicator lamp goes out

and Blind Spot Assist is operational.

If a vehicle is detected within the monitoring

range of Blind Spot Assist at speeds above

30 km/h, warning lamp : on the corre-

sponding side lights up red. This warning

always occurs 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 12 km/h.

The yellow indicator lamp goes out if reverse

gear is engaged. Blind Spot Assist is then

deactivated.

The brightness of the indicator/warning

lamps is adjusted automatically according to

the ambient light.

Blind Spot Assist monitors the area up to

3.0 m behind your vehicle and directly next to

your vehicle, as shown in the picture.

If the lanes are narrow, vehicles driving in the

lane beyond the lane next to your vehicle may

be indicated, especially if the vehicles are not

driving in the middle of their lane. This may be

the caseifthe vehiclesare drivingon the inner

side of their lane.

Due to the nature of the system:

R

warnings may be issued in error when driv-

ing close to crash barriers or similar solid

lane borders

R

warnings may be interrupted when driving

alongside particularly long vehicles, for

example lorries, for a prolonged time

Collision warning

If a vehicle is detected in the monitoring range

of Blind Spot Assist and you switch on the

corresponding turn signal, a double warning

tone sounds. Red warning lamp : flashes. If

the turn signal remains on, detected vehicles

are indicated by the flashing of red warning

lamp :. There are no further warning tones.

Z

Driving systems

228

Activating Blind Spot Assist

tion camera : attached at the top of the

windscreen. Lane Keeping Assistdetects lane

markings on the road and can warn you

before you leave your lane unintentionally.

X

Make sure that Blind Spot Assist is activa-

ted in the on-board computer

(Y page 249).

This function is available in a speed range

between 60 km/h and 200 km/h.

X

Turn the key to position 2 in the ignition

lock.

A warning may be given if a front wheel

passes over a lane marking. It will warn you by

means of intermittent vibration through the

steering wheel for up to 1.5 seconds.

Warning lamps : in the exterior mirrors

light up red for approximately 1.5 seconds

and then turn yellow.

Towing a trailer

Important safety notes

If you couple up a trailer, make sure that you

have correctly established the electrical con-

nection. This can be accomplished by check-

ing the trailer lighting. Blind Spot Assist is

then deactivated. The indicator lamps in the

exterior mirrors light up yellow and the

Blind Spoot Assist not availaable when

towing a ttrailerr SSeeee OOwwnneerr''ss MMaannuuaall

message appears in the multifunction dis-

play.

WARNING

G

Lane Keeping Assist cannot always clearly

identify lane markings.

In these cases, Lane Keeping Assist may:

R

give an unnecessary warning

R

not give a warning

There is a risk of an accident.

Always pay particular attention to the traffic

situation and keep in lane, especially if Lane

Keeping Assist alerts you.

i You can deactivate the indicator lamps in

the exterior mirrors.

To do so, you will need to deactivate Blind

Spot Assist if:

WARNING

G

The Lane Keeping Assist warning does not

return the vehicle to the original lane. There is

a risk of an accident.

R

the key is in position 2 in the ignition lock

R

the engine is not running

R

the electrical connection to the trailer

has been established

Always steer, apply the brakes or accelerate

the vehicle yourself, especially if Lane Keep-

ing Assist alerts you.

Lane Keeping Assist

General notes

If you fail to adapt your driving style, Lane

Keeping Assist can neither reduce the risk of

an accident nor override the laws of physics.

Lane Keeping Assist cannot take into account

road, weather or traffic conditions. Lane

Keeping Assist is only an aid. You are respon-

sible for the distance to the vehicle in front,

forvehiclespeed, forbrakingingoodtimeand

for staying in lane.

Lane Keeping Assist does not keep your vehi-

cle in its lane.

Lane Keeping Assist monitors the area in

front of your vehicle by means of multifunc-

Towing a trailer

229

R

The system may be impaired or may not func-

tion if:

you have switched on the turn signal. In this

event, the warnings are suppressed for a

certain period of time.

a driving safety system intervenes, such as

ABS, BAS or ESP^®.

R

there is poor visibility, e.g. due to insuffi-

cient illumination of the road, or due to

snow, rain, fog or spray

R

you accelerate hard, e.g. kickdown.

you brake hard.

you steer actively, e.g. swerve to avoid an

obstacle or change lane quickly.

R

there is glare, e.g. from oncoming traffic,

the sun or reflection from other vehicles

(e.g. if the road surface is wet)

the windscreen is dirty, misted up, dam-

aged or covered, for instance by a sticker,

in the vicinity of the camera

no or several, unclear lane markings are

present for one lane, e.g. in a construction

area

the lane markings are worn away, dark or

covered up, e.g. by dirt or snow

the distance to the vehicle in front is too

small and the lane markings thus cannot be

detected

the lane markings change quickly, e.g.

lanes branch off, cross one another or

merge

R

you cut the corner on a sharp bend.

In order that you are warned only when nec-

essary and in good time if you cross the lane

marking, the system detects certain condi-

tions and warns you accordingly.

R

The warning vibration occurs earlier if:

R

you approach the outer lane marking on a

bend

the road has very wide lanes, e.g. a motor-

way

R

the system detects solid lane markings

The warning vibration occurs later if:

R

the road is narrow and winding

the road has narrow lanes

R

there are highly variable shade conditions

you cut the corner on a bend

on the road

Activating Lane Keeping Assist

Towing a trailer

X

Activate Lane Keeping Assist using the on-

Important safety notes

board computer; to do so, select Standard

or Adaptive (Y page 249).

If you drive at speeds above 60 km/h and

lane markings are detected, the lane mark-

ings in the assistance graphics display

(Y page 248) are shown in green.

WARNING

G

You could lose control of the vehicle/trailer

combination if it begins to swerve. The vehi-

cle/trailer combination could even overturn.

There is a risk of an accident.

On no account should you attempt to

straighten out the vehicle/trailer combina-

tion by increasing speed. Decrease your

speed and do not countersteer. Brake if nec-

essary.

When Standdard is selected, no warning vibra-

tion occurs if:

R

you have switched on the turn signal. In this

event, the warnings are suppressed for a

certain period of time.

R

a driving safety system intervenes, such as

ABS, BAS or ESP^®.

WARNING

G

If the maximum permissible load for a carrier

system is exceeded, the carrier could come

loose from the vehicle and endanger other

When Adapttive is selected, no warning vibra-

tion occurs if:

Z

Towing a trailer

230

You will find the values approved by the man-

ufacturer on the vehicle identification plates

and those for the towing vehicle under "Tech-

nical data" (Y page 406).

road users. There is a risk of an accident and

injury.

Never exceed the maximum permissible load

when using a carrier.

WARNING

G

Exceeding the maximum permissible nose-

weight of the trailer drawbar on the ball cou-

pling may cause damage to the following:

If you release the ball coupling or it does not

engage correctly when folding in, it will swing

out. Within pivoting range of the ball coupling,

there is an increased risk of an accident and

injury.

R

your vehicle

R

the trailer

R

the ball coupling

trailer tow hitch

Only release the ball coupling if the pivoting

range is unobstructed. Always make sure that

the ball coupling engages when folding in.

R

The vehicle/trailer combination could

become unstable.

If the noseweight used is lower than the min-

imum permissible noseweight, the vehicle/

trailer combination could also become unsta-

ble.

When reversing the vehicle towards the

trailer, make sure there is nobody between

the trailer and the vehicle.

Couple and uncouple the trailer carefully. If

you do not couple the trailer to the towing

vehicle correctly, the trailer could become

detached.

To avoid hazardous situations:

R

make sure to check the noseweight before

each journey

use a drawbar noseweight as close as pos-

sible to the maximum noseweight

When towing a trailer, your vehicle's handling

characteristics will be different in comparison

to when driving without a trailer.

R

The vehicle/trailer combination:

R

do not exceed the maximum permissible

noseweight

do not use a noseweight lower than the

minimum noseweight

Make sure that the following values are not

exceeded:

R

is heavier

R

is restricted in its acceleration and gradi-

ent-climbing capability

has an increased braking distance

is affected more by strong crosswinds

demands more sensitive steering

has a larger turning circle

R

the permissible trailer drawbar noseweight

the permissible trailer load

the permissible rear axle load of the towing

vehicle

the maximum permissible gross vehicle

weight of both the towing vehicle and the

trailer

The applicable permissible values, which

must not be exceeded, can be found:

R

This can impair the vehicle's handling char-

acteristics. Adapt your driving style accord-

ingly. Maintain a safe distance. Drive care-

fully.

When towing a trailer, always adjust your

speed to the current road and weather con-

ditions. Do not exceed the maximum permis-

sible speed for your vehicle/trailer combina-

tion.

R

in your vehicle documents

on the identification plates of the trailer tow

R

hitch and the trailer

R

on the vehicle identification plate

If the values differ, the lowest value applies.

Towing a trailer

231

reasons concerning the operating permit.

This also applies in countries in which the

permissible maximum speed for vehicle/

trailer combinations is above 100 km/h.

When towing a trailer, your vehicle's handling

characteristics will be different in comparison

to when driving without a trailer and it will

consume more fuel.

Change into a lower gear in good time on long

and steep downhill gradients. For vehicles

with automatic transmission, you need to

have selected manual drive program M

(Y page 177).

This also applies if you have activated cruise

control, SPEEDTRONIC or DISTRONIC PLUS.

This will use the braking effect of the engine,

so less braking will be required to maintain

vehicle speed. This relieves the load on the

brake system and prevents the brakes from

overheating and wearing too quickly. If you

need additional braking, depress the brake

pedal repeatedly rather than continuously.

Briefly depressing the accelerator pedal on

downhill gradients while the manual drive

program M is temporarily activated (vehicles

with automatic transmission): the automatic

transmission may switch back to the last

active automatic drive program E or S. The

automatic transmission may shift to a higher

gear. This can reduce the engine's braking

effect.

Notes on towing a trailer

General notes

Trailer towing is not permissible on the fol-

lowing models:

R

A 250 Sport

R

A 250 Sport 4MATIC

R

Mercedes‑AMG A 45 4MATIC

R

A 180 d BlueEFFICIENCY Edition

R

Vehicles with AMG Line

When towing a trailer, set the tyre pressure on

the rear axle of the towing vehicle for the

maximum load. Further information on the

tyre pressure table in the fuel filler flap

(Y page 362).

Please note that when towing a trailer, the

following driving systems have limited avail-

ability or are not available at all.

R

PARKTRONIC (Y page 209)

R

Blind Spot Assist (Y page 226)

The height of the ball coupling changes with

the load of the vehicle. If necessary, use a

trailer with a height-adjustable drawbar.

You will find fitting dimensions and loads

under "Technical data" (Y page 405).

Driving tips

Observe the notes on ESP^®trailer stabilisa-

tion (Y page 76).

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 max-

imum permitted speed is. Observe the legally

prescribed maximum speed in the relevant

country.

Driving tips

If the trailer swings from side to side:

X

Do not accelerate.

X

Do not countersteer.

X

Brake if necessary.

R

Maintain a greater distance to the vehicle in

front than when driving without a trailer.

Avoid braking abruptly. If possible, brake

gently at first to allow the trailer to run on.

Then, increase the braking force rapidly.

The values given for gradient-climbing

capabilities from a standstill refer to sea

level. When driving in mountainous areas,

For certain Mercedes-Benz vehicles, the max-

imum permissible rear axle load is increased

when towing a trailer. See the "Technical

data" section to find out whether this applies

to your vehicle. If you utilise any of the added

maximum rear axle load when towing a trailer,

the vehicle/trailer combination may not

exceed a maximum speed of 100 km/h for

R

Z

Towing a trailer

232

note that the power output of the engine,

and consequently the vehicle's gradient-

climbing capability, decrease with increas-

ing altitude.

Folding out the ball coupling

WARNING

G

If the ball coupling is not correctly engaged,

the trailer can detach. There is a risk of an

accident.

X

Pull out release wheel =.

Turn release wheel = anti-clockwise as far

as it will go.

The ball coupling disengages and folds out

behind the rear bumper. Indicator lamp ?

flashes.

Always engage the ball coupling as described.

WARNING

G

If you release the ball coupling or it does not

engage correctly when folding in, it will swing

out. Within pivoting range of the ball coupling,

there is an increased risk of an accident and

injury.

Only release the ball coupling if the pivoting

range is unobstructed. Always make sure that

the ball coupling engages when folding in.

Before you can tow a trailer with your vehicle,

you must fold out the ball coupling.

The release wheel is located behind the left-

hand side panelling in the luggage compart-

ment.

X

Pull the ball coupling in the direction of the

arrow until it engages in a vertical position.

The indicator lamp on the release wheel

goes out. The power socket folds down

automatically.

The multifunction display shows the

Check traailer hitch lock display mes-

sage until the ball coupling is engaged.

X

Remove the protective covering from the

ball coupling and store it in a safe place.

Make sure that the ball of the ball coupling

is clean and that it is either greased or dry

(grease free), depending on the instruc-

tions for the trailer.

X

To open the cover: turn handle : anti-

clockwise, the fold down and remove

cover ;.

Towing a trailer

233

Coupling up a trailer

Folding in the ball coupling

X

Make sure that the transmission is in posi-

tion P.

WARNING

G

If you release the ball coupling or it does not

engage correctly when folding in, it will swing

out. Within pivoting range of the ball coupling,

there is an increased risk of an accident and

injury.

Only release the ball coupling if the pivoting

range is unobstructed. Always make sure that

the ball coupling engages when folding in.

X

Apply the electric parking brake.

Position the trailer horizontally behind the

vehicle.

Couple up the trailer.

Establish the electric connection between

the vehicle and the trailer.

X

Check that the trailer lighting system is

working.

Fold the ball coupling back in if you are not

using the trailer tow hitch.

The release wheel is located behind the left-

hand side panelling in the luggage compart-

ment.

A connected trailer is only recognised when

the electrical connection is established

correctly and when the lighting system is

working properly. The function of other sys-

tems, such as ESP^®or PARKTRONIC also

depends on this.

X

Place the protective covering on the ball

coupling.

Uncoupling a trailer

WARNING

G

If you uncouple a trailer with an engaged over-

run brake, you could trap your hand between

the vehicle and the trailer drawbar. This poses

a risk of injury.

Do not uncouple a trailer with an engaged

overrun brake.

! Do not disconnect a trailer with an

engaged overrun brake. Otherwise, your

vehicle could be damaged by the rebound-

ing of the overrun brake.

X

To open the cover: turn handle : anti-

clockwise, then fold down and remove

cover ;.

! Remove the installed adapter cable

before folding in the ball coupling. Other-

wise, damage may occur to the rear

bumper and the adapter cable.

X

Make sure that the transmission is in posi-

tion P.

X

Apply the electric parking brake.

X

Secure the trailer against rolling away.

X

Remove the trailer cable and decouple the

trailer.

Z

Towing a trailer

234

X

Pull out release wheel =.

Turn release wheel = anti-clockwise as far

as it will go.

You can find more information about fitting

the trailer electrics at a qualified specialist

workshop.

The ball coupling disengages and folds out

behind the rear bumper. Indicator lamp ?

flashes.

^XTo switch the connected power supply

on or off: turn the key to position 2 or 0

respectively (Y page 157).

Failure check for LEDs

If LED lamps are fitted in the trailer, a mal-

function message may appear in the multi-

function display even if there is no fault. The

reason for the error message may be that the

current has fallen below the minimum of

50 mA.

To ensure reliable operation of the failure

indicator, each LED chain in the trailer lighting

must be guaranteed a minimum current of

50 mA.

X

Press the ball coupling in the direction of

the arrow until it engages behind the

bumper.

The indicator lamp on the release knob and

the message in the multifunction display go

out.

Trailer with 7-pin connector

General notes

Trailer with 7-pin connector: you can con-

nect to the 13-pin socket on the ball coupling

using an adapter or, if necessary, an adapter

cable. Both can be obtained at a qualified

specialist workshop.

Trailer power supply

! You can connect accessories to the per-

manent power supply up to a maximum of

240 W.

You cannot charge a trailer battery using

the power supply.

Fitting the adapter

When it leaves the factory, your vehicle's

trailer socket is equipped with a permanent

power supply and a power supply that is

switched on via the ignition lock.

The permanent power supply is supplied via

trailer socket pin 9.

The power supply that is switched on via the

ignition lock is supplied via trailer socket pin

10.

! Make sure that there is sufficient cable

play so that the cable cannot become

detached when cornering.

! Remove the installed adapter cable

before folding in the ball coupling. Other-

wise, damage may occur to the rear

bumper and the adapter cable.

The trailer's permanent power supply is

switched off in the event of low vehicle supply

voltage and after six hours at the latest.

Towing a trailer

235

X

Open the socket cover.

Insert the plug connector with lug : into

groove = on the socket.

X

Turn bayonet connection ; clockwise to

the stop.

X

Let the cover engage.

If you are using an adapter cable, secure

the cable to the trailer with cable ties.

Z

236

Driving and parking -> Towing a trailer for Your Mercedes A Class 4 Door Third Generation (2012-2017)

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