337
If and when
Starting assistance
Introduction If the engine fails to start because of a discharged battery, the battery of an-
other v
ehic
le can be used to start the engine. Before starting, check the
magic eye on the battery ⇒ page 288.
For starting assistance, jump lead cables conforming to the standard
DIN 72553 are required (see the cable manufacturer instructions). The jump
lead cable must be at least 25 mm 2
in section (0.038 inches 2
) for petrol en-
gines, and 35 mm 2
(0.054 inches 2
) for diesel engines.
For vehicles whose battery is not in the engine compartment, the jump
leads should only be connected to the starting assistance connection
points in the engine compartment.
Additional information and warnings:
● Starter assist systems (Start-Stop function) ⇒ pag
e 194
● Working in the engine compartment ⇒ pag
e 275
● Selective Catalytic Reduction (AdBlue) ⇒ pag
e 271
● Vehicle battery ⇒ pag
e 288 WARNING
Incorrect use of jump leads and incorrectly jump starting could cause the
batt er
y to explode resulting in serious injury. Please observe the follow-
ing rules to minimise the risk of a battery explosion:
● All work involving the vehicle battery and electrical system can cause
corro
sion, fire and serious electric shocks. Always read and take into ac-
count the safety warnings and standards before beginning work on the
battery ⇒ page 288, Vehicle battery. WARNING (Continued)
● The b attery providing current must have the same voltage (12V) and
ap pr
oximately the same capacity (see markings on battery) as the flat
battery.
● Never charge a frozen or recently thawed battery. A flat battery can
freeze at
temperatures around 0°C (+32°F).
● If a battery is frozen and/or has been frozen then it must be replaced.
● A highly explosive mixture of gases is released when the battery is
being ch
arged. Always keep lit cigarettes, open flames, sparks and fire
far from the battery. Never use a mobile telephone when connecting and
removing the jump leads.
● Charge the battery only in well ventilated areas given that when the
batter
y is charged by outside assistance, it creates a mix of highly explo-
sive gases.
● Jump leads should never enter into contact with moving parts in the
engine comp
artment.
● Never switch the positive and negative poles or connect the jump
lea
ds incorrectly.
● Note the instructions provided by the manufacturer of the jump leads. CAUTION
To avoid considerable damage to the vehicle electrical system, note the fol-
low in
g carefully:
● If the jump leads are incorrectly connected, this could result in a short
circ
uit.
● The vehicles must not touch each other, otherwise electricity could flow
as soon a
s the positive terminals are connected. Safety First Operating instructions Practical tips Technical Data
