Mercedes-Benz GLS Owner's Manual page 397

394 Breakdown assistance
& WARNING Risk of explosion from hydro‐
gen gas igniting
There is a danger of hydrogen gas igniting
when charging the battery if there is a short
circuit or sparks start to form.
Make sure that the positive terminal of
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the connected battery does not come
into contact with vehicle parts.
Never place metal objects or tools on a
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battery.
The described order of the battery
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clamps must be observed when con‐
necting and disconnecting the battery.
When giving starting assistance, always
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make sure that you only connect bat‐
tery terminals with identical polarity.
During starting assistance, you must
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observe the described order for con‐
necting and disconnecting the jump
lead.
Do not connect or disconnect the bat‐
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tery clamps while the engine is running.
& WARNING Risk of explosion during
charging process and starting assistance
During the charging process and starting
assistance, the battery may release an explo‐
sive gas mixture.
Avoid fire, naked flames, creating
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sparks and smoking.
Make sure there is sufficient ventila‐
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tion.
Do not lean over a battery.
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& WARNING Risk of explosion from a fro‐
zen battery
A discharged battery may freeze at tempera‐
tures slightly above or below freezing point.
During starting assistance or battery charg‐
ing, battery gas can be released.
Always allow a battery to thaw before
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charging it or performing starting assis‐
tance.
If the indicator/warning lamps in the instrument
cluster do not light up at low temperatures, it is
very likely that the discharged battery has fro‐
zen. In this case you may neither jump-start the
vehicle nor charge the battery.
The service life of a battery that has been
thawed may be dramatically shortened. The
starting characteristics may be impaired, espe‐
cially at low temperatures.
It is recommended that you have a thawed bat‐
tery checked at a qualified specialist workshop.
All vehicles
* NOTE Damage caused by numerous or
extended attempts to start the engine
Numerous or extended attempts to start the
engine may damage the catalytic converter
due to non-combusted fuel.
Avoid numerous and extended attempts
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to start the engine.