2008 MERCEDES-BENZ B-CLASS HATCHBACK ECU

Trailer towing*
186 Trailer towing*
Fitting the ball coupling
X Make a note of the ball coupling key num-
ber.
i You can use this number to obtain a
replacement key from a Mercedes-Benz
Service Centre. G
Risk of injury
If the ball coupling does not engage cor-
rectly when it is mounted, the vehicle/
trailer combination is not secured and the
trailer could come loose. This could cause
an accident. Fit the ball coupling carefully
and make sure that it engages in position
correctly.
Vehicles without ECO start/stop func-
tion: the attachable ball coupling is on the
right of the stowage compartment in the lug-
gage compartment (Y page 160).
X Open the stowage compartment on the
right-hand side of the luggage compart-
ment.
X Fold the trim downwards. Vehicles without ECO start/stop function
1
Ball coupling
2 Retainer strap
X Undo retainer strap 2.
X Remove ball coupling 1from the ball cou-
pling recess.
Vehicles with ECO start/stop function*:
the attachable ball coupling is in the ball cou-
pling recess in the stowage well underneath
the luggage compartment floor
(Y page 202).
X Open the luggage compartment floor. Vehicles with ECO start/stop function
1
Ball coupling
2 Ball coupling recess
X Remove ball coupling 1from the ball cou-
pling recess.2 1
Protective cap Operation
* optional
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Trailer towing*
1881
Trailer power socket
X Fold trailer power socket 1down. G
Risk of accident
The ball coupling is only securely mounted
when the green mark on the handwheel is
aligned with the green area on the ball cou-
pling and the key can be removed. If the ball
coupling is not securely mounted, it may
come loose.
The ball coupling must be locked and the
key must be removed when towing a trailer.
This is the only way to guarantee that the
ball coupling is secured and cannot come
loose while the vehicle is in motion. If the
ball coupling cannot be locked and the key
cannot be removed, remove the ball cou-
pling and clean it. If the ball coupling can still not be fitted
(locked) after it has been cleaned, remove
the ball coupling. The trailer coupling must
then not be used to tow a trailer, as safe
operation is not guaranteed.
Have the entire trailer coupling checked at
a qualified specialist workshop. Mercedes-
Benz recommends that you use a
Mercedes-Benz Service Centre for this pur-
pose. In particular, work relevant to safety
or on safety-related systems must be car-
ried out at a qualified specialist workshop. Notes on towing a trailer
G
Risk of accident
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.
Make sure that the following values are not
exceeded: R
the permissible trailer drawbar nose-
weight
R the permissible trailer load
R the permissible rear axle load of the tow-
ing vehicle
R the maximum permissible gross vehicle
weight of both the towing vehicle and the
trailer
You will find the applicable permissible val-
ues, which must not be exceeded, in the
vehicle documents.
You will find the values approved by the
manufacturer on the vehicle identification
plates and those for the towing vehicle in
the "Technical data" section.
You will find installation dimensions and loads
in the "Technical data" section
(Y page 289).
The maximum permissible trailer drawbar
noseweight on the ball coupling is 75 kg.
However, the actual drawbar load must not
exceed the value given on the trailer coupling
and trailer identification plates. The lowest
weight applies.
! Use a noseweight as close as possible to
the maximum permissible noseweight. Do Operation
* optional
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Trailer towing*
190note that the power output of the engine,
and consequently the vehicle's gradient-
climbing capability, decrease with increas-
ing altitude.
If the trailer swings from side to side:
X Do not accelerate.
X Do not counter-steer.
X Brake if necessary. G
Risk of accident
On no account should you attempt to draw
the vehicle/trailer combination out by
increasing speed. Removing the ball coupling
X Pull the protective cap off the lock in the
handwheel.
X Insert the key into the lock in the hand-
wheel.
X Turn the key clockwise.
The lock is unlocked.
X Hold the ball coupling. Pull the handwheel
away from the ball coupling and turn it
clockwise until it engages.
The green area on the ball coupling is
aligned with the red mark on the hand-
wheel. X
Pull out the ball coupling downwards.
X Clean the ball coupling if it is dirty.
X Vehicles without ECO start/stop func-
tion*: open the stowage compartment on
the right of the luggage compartment.
X Fold the trim downwards.
X Vehicles with start/stop function*:
open the luggage compartment floor.
X Remove the protective cap from the ball
coupling recess.
X Press the protective cap into the ball cou-
pling recess until it engages.
Storing the ball coupling X
Store the ball coupling with the key inser-
ted in the ball coupling recess.
X Vehicle without ECO start/stop func-
tion: Secure the ball coupling in place using
the retainer strap. G
Risk of accident
Do not carry the ball coupling in the vehicle
interior if it is not secured.
Otherwise, you and others could be injured
by the ball coupling being thrown around if
you: R
brake sharply
R change direction suddenly
R are involved in an accident Trailer power supply
When it leaves the factory, your vehicle's
trailer socket outlet is equipped with a per-
manent 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.
! You can connect consumers with a power
rating of up to 240 W to the permanent
power supply and up to 180 W to the power
supply that is switched on via the ignition
lock.
You must not charge a trailer battery using
the power supply.
The trailer's turn signal lamps are only guar-
anteed to function when bulbs are used.
You can obtain further information about
installing the trailer electrics from a qualified Operation
* optional
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Service
191
specialist workshop, e.g. a Mercedes-Benz
Service Centre.
X To switch the switched power supply on
or off: turn the key in the ignition lock to
position 2or 0, respectively. Trailer with 7-pin connector
If your trailer has a 7-pin connector, you can
connect it to the 13-pin socket on the ball
coupling using an adapter or, if necessary, an
adapter cable. Both of these can be obtained
at a qualified specialist workshop, e.g. at a
Mercedes-Benz Service Centre.
Fitting the adapter 1
Connector with lug
2 Socket with groove X
Fold down socket .
X Open the socket cover.
X Insert the connector with lug 1into
groove 2on the socket and turn the con-
nector clockwise to the stop.
X Make the cover engage.
X If you are using an adapter cable, secure
the cable to the trailer with cable ties.
! Make sure that there is sufficient cable
play so that the cable cannot become
detached when cornering. Service
ASSYST PLUS service interval display
The ASSYST PLUS service indicator informs
you of the next service due date. The multi-
function display shows the service due date:
Service A due in ..days
Service A due in .. km
Service A due now Next service due (example)
The letter indicates how much time the work-
shop will require to carry out the service work.
The letters displayed range from
Afor a short
service duration to Hfor a long service dura-
tion.
The ASSYST PLUS service interval indicator
does not take into account any periods of Operation
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Where will I find...?
200 Where will I find...?
Vehicle tool kit, jack and folding
wheel chock
The vehicle tool kit, the folding wheel chock
and the jack are in the left-hand stowage
compartment behind the rear seat backrest. G
Risk of injury
The jack is designed only to raise and hold
the vehicle for a short time while a wheel
is being changed.
You must use axle stands if you are carrying
out work on the vehicle.
Make sure that the jack is placed on a firm,
non-slip, level surface. Do not use wooden
blocks or similar objects as a jack underlay.
Otherwise, the jack will not be able to ach-
ieve its load-bearing capacity due to the
restricted height.
Do not start the engine at any time while a
wheel is being changed.
Do not lie under the vehicle when it is being
supported by the jack. If you do not raise
the vehicle as described, it could slip off the
jack (e.g. if the engine is started or if a door
or the tailgate is opened or closed) and you
could be seriously injured. i
When using the jack, you should also
observe the safety notes in the "Flat tyre"
section (Y page 252).
X Fold down the left-hand rear seat backrest
(Y page 149).
X Push cover up and fold it to the side. 1
Jack
2 Vehicle tool kit
3 Folding wheel chock
Setting up the foldable wheel chock The folding wheel chock serves as an addi-
tional measure for securing the vehicleagainst rolling away, e.g. when a wheel is
being changed.
1
To fold the plates upwards
2 To fold out the lower plate
3 To insert the plate
X Fold both plates 1upwards.
X Fold out lower plate 2.
X Guide the lugs on the lower plate fully into
openings in base plate 3.Practical advice
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Flat tyre
258 G
Risk of accident
Do not exceed the maximum speed of
80 km/h.
The "max. 80 km/h" sticker must be affixed
within the driver's field of vision.
The vehicle's handling characteristics may
be affected. H
Environmental note
Have the used TIREFIT kit disposed of pro-
fessionally, e.g. at a Mercedes-Benz
Service Centre.
X Have the TIREFIT kit replaced every four
years at a qualified specialist workshop,
e.g. a Mercedes-Benz Service Centre. Changing a wheel/fitting the spare
wheel*
G
Risk of accident
The wheel dimensions and tyre size of the
"Minispare" emergency spare wheel* may
differ from those of the standard wheels.
Your vehicle's handling characteristics will
change when a "Minispare" emergency
spare wheel* is fitted. Adapt your style of
driving accordingly.
The "Minispare" emergency spare wheel*
may only be used for a short time. Do not
exceed the maximum speed of 80 km/h
and do not deactivate ESP ®
.
Never drive the vehicle with more than one
"Minispare" emergency spare wheel* fit-
ted. G
Risk of accident
Have the "Minispare" emergency spare
wheel* or the spare wheel* replaced with
a new wheel as soon as possible at a quali-
fied specialist workshop which has the nec-
essary specialist knowledge and tools to
carry out the work required. Mercedes-
Benz recommends that you use a
Mercedes-Benz Service Centre for this pur- pose. In particular, work relevant to safety
or on safety-related systems must be car-
ried out at a qualified specialist workshop.
Preparing the vehicle X
Prepare the vehicle as described
(Y page 252).
X If a trailer is coupled, uncouple it.
X Place the wheels in the straight-ahead posi-
tion.
X Take the "Minispare" emergency spare
wheel* or the spare wheel* out of the stow-
age well under the luggage compartment
floor.
X Take the following out of the stowage com-
partment behind the rear seat backrest:
R
the vehicle tool kit
R the wheel chock
R the jack
X Secure the vehicle to prevent it from rolling
away.
On level ground: place chocks or similar
items under the front and rear of the wheel
that is diagonally opposite the wheel you
wish to change. Practical advice
* optional
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Jump-starting
266 Reconnecting the battery
! Always reconnect the battery in the
sequence described below. Never swap the
terminal clamps. You may otherwise dam-
age the vehicle electronics.
X Switch off all electrical consumers.
X Connect the positive terminal clamp and
secure the cover.
X Connect the negative terminal clamp.
X Connect the breather hose. Make sure that
a cell cap is fitted on the side.
i If the battery power supply has been inter-
rupted (e.g. if it has been reconnected), you
must carry out the following tasks:
R set the time (Y page 108).
R reset the function for folding the exterior
mirrors in/out automatically* by folding
the mirrors out once (Y page 71).
R reset the side windows (Y page 84) Jump-starting
If your vehicle's battery is discharged, the
engine can be jump-started from another
vehicle or from an external battery using jump
leads.
Observe the following points:
R Jump-starting may only be performed when
the engine and catalytic converter are cold.
R Do not start the engine if the battery is fro-
zen. Let the battery thaw first.
R Jump-starting may only be performed from
batteries with a nominal voltage of 12 V.
R Only use jump leads which have a sufficient
cross-section and insulated terminal
clamps.
i Jump leads and further information about
jump-starting can be obtained from any
Mercedes-Benz Service Centre.
! Avoid repeated and lengthy starting
attempts.
Never start the vehicle using a rapid battery
charger. G
Risk of injury
There is a risk of acid burns when jump-
starting a vehicle due to the gases which
escape from the battery. Do not lean over
the battery while the engine is being jump-
started. G
Risk of explosion
Gases escaping from the battery during
jump-starting may cause minor explosions.
Avoid creating sparks. Keep naked flames
away from the battery, and do not smoke.
Comply with safety precautions and take
protective measures when handling batter-
ies. You will find these under "Battery" in
the index.
X Make sure that the two vehicles do not
touch.
X Apply the parking brake.
X Manual transmission: engage neutral.
X AUTOTRONIC*: move the DIRECT SELECT
selector lever to P.
X Switch off all electrical consumers.
X Open the bonnet (Y page 171). Practical advice
* optional
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Towing and tow-starting
268
When towing, observe the legal requirements
in all countries concerned.
! When towing, pull away slowly and with-
out jerking. If the tractive power is too high,
the vehicles could be damaged.
! Do not use the towing eye for recovery,
as this could damage the vehicle. If in
doubt, recover the vehicle with a crane.
! You may tow the vehicle for a maximum
of 50 km. A towing speed of 50 km/h must
not be exceeded.
For towing distances over 50 km, the entire
vehicle needs to be lifted up and transpor-
ted.
! Only secure the tow cable or towing bar
to the towing eyes. You may otherwise
damage the vehicle.
R Vehicles with AUTOTRONIC* must not be
tow-started.
R If the engine does not start, try jump-start-
ing it (Y page 266).
R If it is not possible to jump-start the vehicle,
have it towed to the nearest qualified spe-
cialist workshop, e.g. a Mercedes-Benz
Service Centre. R
The selector lever must be in position N
when towing a vehicle with AUTO-
TRONIC*.
R If you are towing the vehicle over a consid-
erable distance, this must only be done
with the front axle raised.
R The ignition must be switched off if you are
towing the vehicle with the front/rear axle
raised. Intervention by ESP ®
could other-
wise damage the brake system.
R Before towing the vehicle, make sure that
the battery is connected and charged. Oth-
erwise:
-you cannot switch on the ignition
- you cannot move the selector lever
to N(on vehicles with AUTOTRONIC*)
- you have no support when braking
i Switch off the automatic locking feature
before the vehicle is towed (Y page 110).
You could otherwise be locked out when
pushing or towing the vehicle. Fitting the towing eye
Vehicles with a trailer tow hitch: if you
intend to use the vehicle for towing, fit the ball
coupling (Y page 186) and connect the tow-
bar to this.
Opening the front cover The mountings for the removable towing eyes
are in the bumpers. They are located at the
front and rear behind covers on the right-hand
side of the vehicle when viewed in the direc-
tion of travel.
1
Cover
X Press cover 1back in the direction of the
arrow.
X Take cover 1off the opening. Practical advice
* optional
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