Battery MERCEDES-BENZ B-CLASS HATCHBACK 2008 Owner's Manual

Troubleshooting
233Engine
Problem Possible cause/consequence Suggested solutions
The engine will not start. You can
hear the starter motor operating. R
The engine electronics system
is malfunctioning.
R There is a malfunction in the
fuel supply.
R The on-board voltage is too low
because the starter battery is
too weak or discharged. X
Turn the key back to position 0(Y page 62) in the ignition lock
before the next starting attempt.
X Try to start the engine again (Y page 86). When doing so, remember
that excessively long and frequent attempts to start the engine will
drain the battery.
If the engine does not start after several attempts:
X Consult a qualified specialist workshop. The engine will not start. You can
hear the starter motor operating.
The reserve fuel warning lamp is
on and the fuel gauge shows
0. The fuel tank has been run dry. X
Refuel the vehicle.
X Bleed the fuel system (Y page 232).The engine will not start. You can-
not hear the starter motor oper-
ating. The on-board voltage is too low
because the starter battery is too
weak or discharged. X
Jump-start the vehicle (Y page 266).
If the engine does not start despite attempting 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. Practical advice
245_AKB; 2; 7, en-GB
wdomann,
Version: 2.11.4
2008-10-17T11:22:31+02:00 - Seite 233 ZDateiname: 6515_1640_02_buchblock.pdf; preflight

Troubleshooting
239Key
Problem Possible cause/consequence Suggested solutions
You cannot lock or unlock the
vehicle using the key. The key batteries are discharged
or nearly discharged. X
Point the tip of the key at the driver's door handle from close range
and try to unlock or lock the vehicle again.
If this does not work:
X Unlock the vehicle using the emergency key element
(Y page 241).
X Check the key batteries (Y page 244) and replace them if neces-
sary (Y page 244). The key is faulty. X
Unlock the vehicle using the emergency key element
(Y page 241).
X Have the key checked at a qualified specialist workshop. The battery charge indicator lamp
of the key does not go on during
the test. The key batteries are discharged. X
Change the batteries (Y page 244).You have lost a key. X
Have the key cancelled at a Mercedes-Benz Service Centre.
X Report the loss immediately to the vehicle insurers.
X If necessary, have the manual locks changed too. You have lost the emergency key
element. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the manual locks changed too. The engine cannot be started
using the key. The steering lock is mechanically
blocked. X
Remove the key and reinsert it into the ignition lock. While doing
this, turn the steering wheel in both directions. Practical advice
245_AKB; 2; 7, en-GB
wdomann,
Version: 2.11.4
2008-10-17T11:22:31+02:00 - Seite 239 ZDateiname: 6515_1640_02_buchblock.pdf; preflight

Troubleshooting
240 Trailer towing
Problem Possible cause/consequence Suggested solutions
The ball coupling cannot be
locked.
The key cannot be removed from
the ball coupling.
G
Risk of accident
The ball coupling is dirty.
The trailer tow hitch is damaged. X
Remove the ball coupling and clean it (Y page 196). If the ball cou-
pling still cannot be locked, remove the ball coupling. It must no
longer be used to tow a trailer, as safe operation is not guaranteed.
X Have the entire trailer tow hitch checked at a qualified specialist
workshop. Parking up the vehicle
Problem Possible cause/consequence Suggested solutions
The vehicle is to be left parked up
for longer than six weeks. Damage resulting from non-use
may occur if the vehicle is parked
up for long periods. X
Visit a qualified specialist workshop and seek advice.
X Disconnect the battery ( Ypage 264). Practical advice
245_AKB; 2; 7, en-GB
wdomann,
Version: 2.11.4 2008-10-17T11:22:31+02:00 - Seite 240Dateiname: 6515_1640_02_buchblock.pdf; preflight

Changing the batteries
243Releasing the parking lock manually
on vehicles with AUTOTRONIC*
In the event of an electrical fault, it is possible
to release the selector lever lock manually to
move it out of position P, e.g. if you wish to
tow the vehicle away. 1
Cup holder
X Apply the parking brake.
X Pull up cup holder 1. Releasing the parking lock manually
1
Screwdriver or similar implement
2 Release pin G
Risk of injury
Release pin 2can become very hot. There-
fore only press the release pin with a suit-
able screwdriver or similar implement; oth-
erwise, you could burn yourself.
X Use implement 1to press release pin 2
and simultaneously move the selector lever
out of position P.
The selector lever can now be moved freely
until it is returned to position P. Changing the batteries
Notes
It is advisable to have the batteries replaced
at a qualified specialist workshop, e.g. at a
Mercedes-Benz Service Centre. G
Risk of poisoning
Batteries contain toxic and caustic sub-
stances. For this reason, keep batteries
away from children.
If a battery is swallowed, consult a doctor
immediately. H
Environmental note
Do not dispose of batteries with the house-
hold rubbish. They contain highly toxic sub-
stances.
Take discharged batteries to a qualified
specialist workshop, e.g. a Mercedes-Benz
Service Centre, or to a special collection
point for old batteries. Practical advice
* optional
245_AKB; 2; 7, en-GB
wdomann,
Version: 2.11.4 2008-10-17T11:22:31+02:00 - Seite 243 ZDateiname: 6515_1640_02_buchblock.pdf; preflight

Changing bulbs
244 Key
Checking the batteries X
Press the jork button.
The batteries are in order if the battery
charge indicator lamp lights up briefly.
Changing the batteries You require two CR 2025 3 V cell batteries.
X Remove the emergency key element from
the key (Y page 241). 1
Emergency key element
2 To release the battery tray
3 To pull out the battery tray
4 Battery tray X
Using emergency key element 1, press
the grey release catch in the opening in the
direction of arrow 2.
Battery tray 4is released.
X Pull battery tray 4out of the key in the
direction of arrow 3. X
Remove old batteries 1from the battery
tray.
X Insert the new batteries underneath con-
tact spring 2with the positive terminal
facing upwards. Use a lint-free cloth to do
so.
X Push the battery tray back into the key
housing until the battery tray engages.
X Check the function of all key buttons on the
vehicle. Changing bulbs
Notes on changing bulbs
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times. G
Risk of injury
Bulbs and lamps can be very hot. You
should therefore allow them to cool down
before you change them. Otherwise, you
could be burned if you touch them.
Keep bulbs out of the reach of children.
Otherwise, they could damage them, for
example, and injure themselves.
Never use a bulb which has been dropped.
Such a bulb may explode and injure you.
H7 bulbs are pressurised and could explode
when you change them, particularly if they
are very hot. You should therefore wear eye
protection and gloves when you are chang-
ing them. G
Risk of injury
Xenon bulbs carry a high voltage. You could
get an electric shock and be seriously or
even fatally injured if you touch the electric
contacts on xenon bulbs. Therefore, never
remove the cover from xenon bulbs. Practical advice
245_AKB; 2; 7, en-GB
wdomann
,V ersion: 2.11.4
2008-10-17T11:22:31+02:00 - Seite 244 Dateiname: 6515_1640_02_buchblock.pdf; preflight

Battery
263Battery
Notes on the vehicle battery
In order for the battery to achieve the maxi-
mum possible service life, it must always be
sufficiently charged.
Have the battery charge checked more fre-
quently if you use the vehicle mainly for short
trips or if you leave it standing idle for a
lengthy period.
To prevent damage from corrosion, only
replace the battery with one that has a central
ventilation cover.
Consult a Mercedes-Benz Service Centre if
you wish to leave your vehicle parked up for
a long period of time. G
Risk of injury
Comply with safety precautions and take
protective measures when handling batter-
ies. Risk of explosion
Fire, naked flames and
smoking are prohibited
when handling the bat- tery. Avoid creating
sparks.
Battery acid is caustic.
Avoid contact with the
skin, eyes or clothing.
Wear suitable protective
clothing, in particular
gloves, an apron and a
face mask.
Immediately rinse acid
splashes off with clean
water. Consult a doctor if
necessary.
Wear eye protection.
Keep children away.
Observe this Owner's
Manual.
H
Environmental note
Do not dispose of batteries with the house-
hold rubbish. Dispose of defective batteries
in an environmentally responsible manner. Take them to a Mercedes-Benz Service
Centre or to a special collection point for
old batteries. G
Risk of injury
For safety reasons, Mercedes-Benz recom-
mends that you only use batteries which
have been tested and approved for your
vehicle by Mercedes-Benz. These batteries
provide increased impact protection to pre-
vent vehicle occupants from suffering acid
burns should the battery be damaged in the
event of an accident.
To prevent acid burns, observe the follow-
ing safety notes when handling batteries:
R Do not lean over batteries.
R Do not place any metal objects on a bat-
tery. You could otherwise cause a short
circuit and the battery's gas mixture
could ignite.
R Make sure that you do not create an elec-
trostatic charge, e.g. by wearing syn-
thetic clothing or as a result of friction on
fabrics. Therefore, you should not pull or
slide the battery over carpets or other
synthetic materials.
R Never touch the battery first. To dis-
charge a possible electrostatic charge, Practical advice
245_AKB; 2; 7, en-GB
wdomann,
Version: 2.11.4 2008-10-17T11:22:31+02:00 - Seite 263 ZDateiname: 6515_1640_02_buchblock.pdf; preflight

Battery
264 step out of the vehicle first and touch the
bodywork.
R Do not wipe the battery using a cloth. The
battery could be destroyed as a result of
electrostatic charge or due to flying
sparks.
! Switch off the engine and remove the key
before disconnecting the terminal clamps
from the battery. Otherwise, you may
destroy electronic components, such as
the alternator.
i Mercedes-Benz recommends that you
have all work involving the battery, e.g.
removing, charging and replacing, carried
out at a qualified specialist workshop, e.g.
a Mercedes-Benz Service Centre.
Installation location of the battery Your vehicle is equipped with a battery in the
footwell in front of the front-passenger seat.
The main fuse box is also located there. 1
Retaining screw
2 Cap
X Remove the floormat*.
X Remove retaining screw 1by turning it
anti-clockwise, e.g. by using a coin.
X Lift up cover 2. 3
Negative terminal
4 Positive terminal Disconnecting the battery
G
Risk of accident
If the battery is disconnected:
R the brake boosting effect will not be avail-
able. Greater braking force will then be
required and the brake pedal travel will
be longer. If necessary, depress the
brake pedal with maximum force.
R you will no longer be able to turn the key
in the ignition lock.
R the selector lever is locked in position P
on vehicles with AUTOTRONIC*. Practical advice
* optional
245_AKB; 2; 7, en-GB
wdomann,
Version: 2.11.4 2008-10-17T11:22:31+02:00 - Seite 264Dateiname: 6515_1640_02_buchblock.pdf; preflight

Battery
265
!
Always disconnect the battery in
the order described below. Never swap the
terminal clamps. Otherwise, you may dam-
age the vehicle electronics.
X Apply the handbrake and shift the selector
lever to position Pon vehicles with AUTO-
TRONIC*.
X Switch off all electrical consumers.
X Turn the key to position 0(Y page 62) in
the ignition lock and remove it.
X Remove the negative terminal clamp from
the battery.
X Remove the cover from the positive termi-
nal clamp.
X Remove the positive terminal clamp from
the battery.
X Disconnect the breather hose. Removing the battery
X Disconnect the battery ( Ypage 264).
X Loosen the bolt which holds the battery in
place.
X Remove the battery. Charging and fitting the battery
G
Risk of injury
Only charge the battery in a well-ventilated
area. As the battery is being charged, gases
can escape and generate minor explosions.
This may injure you and other persons or
cause damage to the paintwork or acid cor-
rosion on the vehicle.
You can obtain information about battery
chargers which allow the battery to be
charged when still installed from a qualified
specialist workshop, e.g. a Mercedes-Benz
Service Centre. G
Risk of injury
There is a risk of acid burns during the
charging process due to the gases which
escape from the battery. Do not lean over
the battery during the charging process. G
Risk of injury
Battery acid is caustic. Avoid contact with
the skin, eyes or clothing.
! Only charge the installed battery with a
battery charger which has been tested and
approved by Mercedes-Benz. These battery
chargers allow the battery to be charged
while it is still installed. However, the bat-
tery must always be disconnected first.
! Only use battery chargers with a maxi-
mum charging voltage of 14.8 V.
X Charge the battery. Observe the notes in
the operating instructions for your battery
charger.
X Refit the charged battery.
To do this, follow the steps described in
"Removing the battery" (Y page 265) in
reverse order. Practical advice
* optional
245_AKB; 2; 7, en-GB
wdomann,
Version: 2.11.4
2008-10-17T11:22:31+02:00 - Seite 265 ZDateiname: 6515_1640_02_buchblock.pdf; preflight

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
245_AKB; 2; 7, en-GB
wdomann,
Version: 2.11.4 2008-10-17T11:22:31+02:00 - Seite 266Dateiname: 6515_1640_02_buchblock.pdf; preflight

Towing and tow-starting
2671
Positive terminal of donor battery
2 Positive terminal on your vehicle
3 Negative terminal of donor battery
4 Negative terminal on your vehicle
X Open the battery cover ( Ypage 264).
X Connect positive terminal 2on your vehi-
cle to positive terminal 1of the donor bat-
tery using the jump lead, beginning with
your own battery.
X Start the engine of the donor vehicle and
run it at idling speed.
X Connect negative terminal 3of the donor
battery to negative terminal 4of your
vehicle's battery using the jump lead, con-
necting the jump lead to the donor battery
first.
X Start the engine. X
Electrical consumers can be switched on
again. Do not, however, switch on the lights
as this places too heavy a load on the bat-
tery.
X Remove the jump lead from earth
point 4and negative terminal 3first,
then from positive terminals 1and 2,
each time disconnecting from the battery
on your own vehicle first.
X Have the battery checked at a qualified
specialist workshop, e.g. a Mercedes-Benz
Service Centre. Towing and tow-starting
Points to remember
G
Risk of accident
If you have the vehicle towed, you must use
a rigid towing bar if:
R the engine is not running.
R there is a brake system malfunction.
R there is a malfunction in the voltage sup-
ply or the vehicle's electrical system.
The electric power steering and the brake
force booster do not work when the engine
is not running. Greater braking force will
then be required and brake pedal travel will
be longer. If necessary, depress the brake
pedal with full force.
Do not tow the vehicle if the key cannot be
turned in the ignition lock. If this is the case,
the steering is locked and the vehicle can-
not be steered.
If you tow or tow-start another vehicle, its
weight must not exceed the maximum per-
missible gross vehicle weight of your vehi-
cle.
It is better to have the vehicle transported
than to have it towed. Practical advice
245_AKB; 2; 7, en-GB
wdomann,
Version: 2.11.4 2008-10-17T11:22:31+02:00 - Seite 267 ZDateiname: 6515_1640_02_buchblock.pdf; preflight