249
If and when
Jump leads
Jump leads must comply with standard DIN 72553 (see cable manufactur-
er's instructions). The wire cross section must be at least 25 mm 2
for petrol
engines and at least 35 mm 2
for diesel engines.
Note
● The vehicles must not touch each other, otherwise electricity could flow
as soon as the positive terminals are connected.
● The discharged battery must be properly connected to the on-board net-
work.
How to jump start: description
Fig. 178 Diagram of con-
nections for vehicles
without Start-Stop sys-
tem
Fig. 179 Diagram of con-
nections for vehicles
with Start-Stop system
Jump lead terminal connections
1. Switch off the ignition of both vehicles ⇒
.
2. For vehicles without Start-Stop system :
– Connect one end of the red jump lead to the positive +
termi-
nal of the vehicle with the flat battery A ⇒ Fig. 178.
– Connect the other end of the red jump lead to the positive ter-
minal +
in the vehicle providing assistance B.
– Connect one end of the black jump lead to the negative terminal
–
of the vehicle providing assistance B ⇒ Fig. 178.
– Connect the other end of the black jump lead X
to a solid met-
al component bolted to the engine block or to the engine block
itself of the vehicle with the flat battery. However, connect it to
a point as far as possible from the battery A
.
3. For vehicles with Start-Stop system :
Safety FirstOperating InstructionsPractical TipsTechnical Specifications
250If and when
–Connect one end of the red jump lead to the positive +
termi-
nal of the vehicle with the flat battery A ⇒ Fig. 179.
– Connect the other end of the red jump lead to the positive ter-
minal +
in the vehicle providing assistance B.
– Connect one end of the black jump lead X
to a suitable ground
terminal, a solid piece of metal in the engine block, or to the en-
gine block ⇒ Fig. 179.
– Connect the other end of the black jump lead X
to a solid met-
al component bolted to the engine block or to the engine block
itself of the vehicle with the flat battery. However, connect it to
a point as far as possible from the battery A
.
4. Position the leads in such a way that they cannot come into contact with any moving parts in the engine compartment.
Starting
5. Start the engine of the vehicle with the boosting battery and let it run at idling speed.
6. Start the engine of the vehicle with the flat battery and wait two or three minutes until the engine is “running”.
Removing the jump leads
7. Before you remove the jump leads, switch off the dipped beam headlights (if they are switched on).
8. Turn on the heater blower and heated rear window in the vehi- cle with the flat battery. This helps minimise voltage peaks
which are generated when the leads are disconnected.
9. When the engine is running, disconnect the leads in reverse or- der to the details given above. Connect the battery clamps so they have good metal-to-metal contact with
the battery terminals.
If the engine fails to start, switch off the starter after about 10 seconds and
try again after about half a minute.
WARNING
● Please note the safety warnings referring to working in the engine
compartment ⇒ page 200, Working in the engine compartment.
● The battery providing assistance must have the same voltage as the
flat battery (12V) and approximately the same capacity (see imprint on
battery). Failure to comply could result in an explosion.
● Never use jump leads when one of the batteries is frozen. Danger of
explosion! Even after the battery has thawed, battery acid could leak and
cause chemical burns. If a battery freezes, it should be replaced.
● Keep sparks, flames and lighted cigarettes away from batteries, dan-
ger of explosion. Failure to comply could result in an explosion.
● Observe the instructions provided by the manufacturer of the jump
leads.
● Do not connect the negative cable from the other vehicle directly to
the negative terminal of the flat battery. The gas emitted from the battery
could be ignited by sparks. Danger of explosion.
● Do not attach the negative cable from the other vehicle to parts of the
fuel system or to the brake line.
● The non-insulated parts of the battery clamps must not be allowed to
touch. The jump lead attached to the positive battery terminal must not
touch metal parts of the vehicle, this can cause a short circuit.
● Position the leads in such a way that they cannot come into contact
with any moving parts in the engine compartment.
● Do not lean on the batteries. This could result in chemical burns.
