switched on. They will go out if you drive a short distance at a speed of 15 – 20 km/h (10 – 12 mph). If the indicator
lamps remain lit up, the vehicle should be checked by a qualified workshop.
If the 12-volt vehicle battery was disconnected for an extended period, the system may not able to calculate or
correctly display the time when the next service is due (→ Instrument cluster). Observe the maximum permissible
service intervals .
Automatic switch-off for electrical consumers
An intelligent vehicle electrical system management function automatically implements a range of measures to
prevent the 12-volt battery from discharging under high loads:
—The performance of large electrical consumers may be reduced or they may be switched off completely.
The vehicle electrical system cannot always prevent the 12-volt vehicle battery from discharging. For example, if the
ignition is switched on for an extended period when the vehicle’s drive system is deactivated, or if the side or parking
lights are on when the vehicle is parked for an extended period.
What causes the 12-volt vehicle battery to discharge?
The 12-volt vehicle battery will discharge if you use electrical consumers when the engine is switched off.
WARNING
Incorrectly securing the battery and using incorrect 12-volt vehicle batteries can cause short circuits, fire and
serious injuries.
● Always use maintenance-free and leak-proof 12-volt vehicle batteries that have the same properties,
specifications and dimensions as the factory-fitted 12-volt vehicle battery.
● In vehicles with the 12-volt vehicle battery in the luggage compartment or vehicle interior, ensure that the
breather hose is connected properly to the 12-volt vehicle battery. Make sure that there is no open ventilation
opening in the area of the positive terminal. If an open ventilation opening is located in this area, it must be
blocked with a sealing plug. The breather hose must be connected to the open ventilation opening in the area of
the negative battery terminal.
NOTICE
● Never connect or disconnect 12-volt vehicle batteries when the electric drive is activated. Never use a 12-volt
vehicle battery that does not correspond with the vehicle's specifications. This can damage the electrical system
or electronic components, which can cause electrical faults.
● Never connect equipment that provides electric power, such as solar panels or a battery charger, to the 12-volt
sockets or to the cigarette lighter to charge the 12-volt vehicle battery. This can damage the vehicle electrical
system.
Dispose of the 12-volt vehicle battery in accordance with the regulations. 12-volt vehicle batteries may
contain toxic substances such as sulphuric acid and lead.
Electrolyte can pollute the environment. Clean up any service fluid leakages and dispose of them
properly.
Troubleshooting
12-volt vehicle battery
The indicator lamp lights up red. The following text messages can be displayed:
—12V battery is not charging. Safely stop the vehicle!or
—Fault: 12V battery is not charging. Safely stop the vehicle!or
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