The essentials
starting, check the magic eye on the battery
› ›
›
page 283.
For starting assistance, jump lead cables con-
forming to the standard DIN 72553 are re-
quired (see the cable manufacturer instruc-
tions). The jump lead cable must be at least
25 mm 2
in section (0,038 inches 2
) for petrol
engines, and 35 mm 2
(0,054 inches 2
) for die-
sel engines.
For vehicles whose battery is not in the en-
gine compartment, the jump leads should
only be connected to the starting assistance
connection points in the engine compart-
ment. WARNING
Incorrect use of jump leads and incorrectly
jump st ar
ting could cause the battery to ex-
plode resulting in serious injury. Please ob-
serve the following rules to minimise the risk
of a battery explosion:
● The battery providing current must have
the same v
oltage (12V) and approximately
the same capacity (see markings on battery)
as the flat battery.
● Never charge a frozen or recently thawed
batter
y. A flat battery can also freeze at tem-
peratures close to 0°C (+32°F).
● If a battery is frozen and/or has been frozen
then it mus
t be replaced.
● A highly explosive mixture of gases is re-
lea
sed when the battery is being charged. Al- ways keep lit cigarettes, flames, sparks and
fire f
ar fr
om the battery. Never use a mobile
telephone when connecting and removing the
jump leads.
● Charge the battery only in well ventilated
area
s given that when the battery is charged
by outside assistance, it creates a mix of
highly explosive gases.
● Jump leads should never enter into contact
with mov
ing parts in the engine compart-
ment.
● Never switch the positive and negative
pole
s or connect the jump leads incorrectly.
● Note the instruction manual provided by
the manufact
urer of the jump leads. CAUTION
To avoid considerable damage to the vehicle
electric a
l system, note the following careful-
ly:
● If the jump leads are incorrectly connected,
this c
ould result in a short circuit.
● The vehicles must not touch each other,
otherwi
se electricity could flow as soon as
the positive terminals are connected. Positive pole on the jump lead con-
nection point
s Fig. 73
In the engine compartment: positive
po l
e f
or starting assistance + .
On some vehicles, there is a starting assis-
t
anc
e t
erminal in the engine compartment,
under a labelled cover. 53
Checking and refilling levels
Checking the electrolyte level of the
v ehic
l
e battery Fig. 249
In the engine compartment: remove
the lid fr om the
v
ehicle's battery. Fig. 250
In the engine compartment: lift off
the c o
v
er from the vehicle's battery. Read the additional information carefully
› ›
›
page 42
The battery's electrolyte level should be
checked regularly in high-mileage vehicles, in hot countries and in older batteries. Other
batterie
s do not require maintenance.
Vehicles with a Start-Stop system
( ››› page 209) are equipped with a special
battery marked with the letters “AGM”. For
technical reasons, it is not possible to check
the electrolyte level of these batteries
Preparations
● Prepare the vehicle for work in the engine
compar
tment ››› page 271
● Open the bonnet ›››
page 271.
Opening the battery cover
The battery covers are different depending on
the engine size of the vehicle:
● In the case of a lid: pres
s the tab ››› Fig. 249
A in the direction of the arrow and pull the
c o
v
er upwards.
● In the case of a cover: fol
d the cover to one
side to remove ››› Fig. 250.
Checking the battery electrolyte level
● Make sure there is sufficient lighting to
cle
arly recognise the colours. Never use
flames or flashing objects as a light source.
● Depending on the level of acid, the Magic
eye on the top of
the battery will change col-
our.
Colour indi-
catorNecessary operations
Light yellow or
ColourlessThe electrolyte level of the vehicle's
battery is too low. Have the battery
checked and, where applicable, re-
placed by a specialised workshop.
BlackThe electrolyte level of the vehicle's
battery is correct. WARNING
Working with the vehicle battery involves a
risk of
corrosion, explosions or electric
shock.
● Never tilt the vehicle battery. Battery acid
coul
d spill out of the openings for the release
of gases and cause corrosion damage.
● Never open the vehicle battery.
● If battery acid splashes on you, immediate-
ly rinse
your eyes and skin abundantly with
water for several minutes. Then seek medical
care immediately.
● If acid is swallowed by mistake, consult a
doctor immediat
ely. Charging, replacing and connecting or
di
s
c
onnecting the battery Charging the battery
The
vehic
le battery should be charged by a
specialised workshop only, as batteries us-
ing special technology have been installed »
285
Technical data
Advice
Operation
Emergencies
Safety
