•Switch off all electrical consumers and the ignition.
•Unlock the vehicle before disconnecting the battery in order to avoid triggering the anti-theft
alarm.
•First disconnect the negative cable and then the positive cable ⇒.
Connecting the 12-volt vehicle battery
•Switch off all electrical consumers and the ignition before reconnecting the 12-volt vehicle
battery.
•First reconnect the positive cable and then the negative cable ⇒.
Various indicator lamps may light up after the 12-volt vehicle battery has been connected and the
ignition is switched on. They will go out if you drive a short distance at a speed of approximately
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 ⇒ Service.
Vehicles with Keyless Access:⇒ Central locking system: if the ignition cannot be switched on after
connecting the 12-volt vehicle battery, lock and unlock the vehicle from the outside. Then try to start
the ignition again. Please contact an expert if the ignition cannot be switched on.
Automatic switch-off for electrical consumers
The intelligent vehicle electrical system management automatically implements a range of
measures to prevent the 12-volt battery from discharging under high loads:
•The idling speed is increased so that the alternator provides more electricity.
•The performance of large electrical consumers may be reduced or they may be switched off
completely.
•The power supply to the 12-volt socket and the cigarette lighter is interrupted temporarily while
the engine is being started.
The vehicle electrical system management function cannot always prevent the 12-volt vehicle
battery from discharging. For example when the ignition is switched on for an extended period with
the engine off, or when the side or parking lights are on when the vehicle is parked for an extended
period.
Battery switch-off in an accident in which the airbag is triggered
In vehicles with 12-volt vehicle battery in the luggage compartment, the electrical connection to the
12-volt vehicle battery is disconnected pyrotechnically in the event of an accident in which the
airbags are triggered. This prevents short-circuiting.
What can cause the 12-volt vehicle battery to discharge?
•Long periods at a standstill in which the engine is not running, especially if the ignition is
switched on.
•The use of electrical consumers when the engine is switched off.
•When the auxiliary heater is being used ⇒ Auxiliary heater and ventilation.
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
First read and observe the introductoryinformation and safety warnings⇒
Introduction
12-volt vehicle battery
Fault in the alternator. Go to a qualified workshop. Have the electrical system checked. Switch
off any electrical consumers that are not required. The 12-volt vehicle battery will not be charged by
the alternator while the vehicle is in motion. The start/stop system cannot start the engine.
⇒ Start/stop system
Wheels and tyres
Tyre monitoring systems
Introduction
This chapter contains information on the followingsubjects:
⇒ Types of tyre monitoring systems
⇒ Tyre Pressure Loss Indicator
⇒ Tyre Pressure Monitoring System
⇒ Troubleshooting for the Tyre Pressure Loss Indicator
⇒ Troubleshooting for the Tyre Pressure Monitoring System
The tyre monitoring system warns the
driver when the tyre pressures get too
low.
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, ensure that the
breather hose is connected properly to the 12-volt vehicle battery. Make sure that no
open gas discharge openings are located in the area around the positive battery
terminal. If there is an open breather opening in this area, it must be closed off with a
sealing plug. The breather hose must be connected to the open breather opening in the
area of the negative terminal.
WARNING
A highly explosive mixture of gases is given off when the 12-volt vehicle battery is being
charged.
•12-volt vehicle batteries should only be charged in well-ventilated spaces.
•Never charge a 12-volt vehicle battery that is frozen or that has thawed. Discharged 12-
volt vehicle batteries can already freeze at temperatures of around 0°C (+32°F).
•The 12-volt vehicle battery must be replaced if it has ever been frozen.
•Incorrectly connected cables can cause a short circuit. First connect the positive cable
and then the negative cable.
WARNING
•Never connect or disconnect 12-volt vehicle batteries if the ignition is switched on or
the engine is running. 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 supplies electric power, such as solar panels or a
battery charger, to the 12-volt socket or to the cigarette lighter to charge the 12-volt
vehicle battery. This can damage the vehicle electrical system.
NOTICE
Useful information about wheels and tyres
Introduction
This chapter contains information on the followingsubjects:
⇒ Handling wheels and tyres
⇒ Wheel rims and wheel bolts
⇒ Tyre pressure
⇒ Tread depth and wear indicators
⇒ Tyre damage
⇒ Spare wheel or temporary spare wheel
⇒ Tyre lettering and tyre type
⇒ Maximum load and speed range for tyres
⇒ Winter tyres
⇒ Snow chains
The tyres are the most used and most underestimated parts of a vehicle. Tyres are very important
as the narrow tyre surfaces are the only contact between the vehicle and the road.
The service life of tyres is dependent on tyre pressure, driving style, handling and correct fitting.
Differing tyre pressures or tyre pressures that are too low can cause tyre damage, tyre
failure, loss of vehicle control, accidents, serious injury and death.
•If the indicator lamp lights up, stop the vehicle as soon as possible and check all
the tyres ⇒ Useful information about wheels and tyres.
•Different tyre pressures or tyre pressures that are too low can increase wear on the
tyres, reduce vehicle stability and increase the braking distance.
•Differing tyre pressures or tyre pressures that are too low can cause sudden tyre
failure and lead to a tyre bursting and the loss of control over the vehicle.
•The driver is responsible for the correct tyre pressure of all tyres on the vehicle. The
recommended tyre pressure can be found on a sticker ⇒ Tyre pressure.
•The tyre monitoring system cannot function correctly until all cold tyres have the
correct tyre pressure.
•The pressure in all tyres must always be appropriate to the vehicle load ⇒ Tyre
pressure.
•Always inflate all tyres to the correct tyre pressure before every journey ⇒ Tyre
pressure.
•If the vehicle is driven with insufficient tyre pressure, this results in greater tyre flexing.
This could warm up the tyre to such an extent that the tread may separate and the tyre
could burst. This could cause the driver to lose control of the vehicle.
•High speeds and overloading of the vehicle may cause the tyres to heat up to such an
extent that the tyre bursts, leading you to lose control of the vehicle.
•If the tyre pressure is too low or too high, the tyres will wear prematurely and the
vehicle will not handle well.
•If the tyre is not flat and it is not necessary to change the wheel immediately, drive at
low speed to the nearest qualified workshop and check and correct the tyre pressure
⇒ Tyre pressure.
WARNING
Removing the spare wheel
•Open the boot lid.
•Raise or fold forward the luggage compartment floor ⇒ Boot lid.
•Pull the wedge of the locating element ⇒ Fig. 239① upwards and out.
•Unscrew the handwheel in the middle of the spare wheel ② anticlockwise fully and remove the
spare wheel.
Storing the removed wheel
•Open the boot lid and raise the luggage compartment floor or fold it forwards.
•Place the removed wheel into the spare wheel well with the rim facing downwards so that the
central hole in the rim positioned exactly above the threaded pin.
•Screw the handwheel ⇒ Fig. 239② clockwise onto the threaded pin until the replaced wheel is
firmly secured.
•Insert the locating element wedge ① into the slot of the threaded pin so that the handwheel can
no longer be turned.
If the spare wheel tyre is not the same as the tyres that are mounted on
the vehicle
If the spare wheel tyre differs from the other tyres on the vehicle, the spare wheel must be used
only in the event of a tyre failure and for a short time ⇒.
Follow these guidelines:
•Do not drive faster than 80 km/h (50 mph).
•Avoid full acceleration, sudden braking and fast driving through bends in the road.
•Do not use snow chains on the temporary spare wheel ⇒ Snow chains.
•The tyre pressure must be checked as soon as possible after fitting the spare wheel or
temporary spare wheel ⇒ Tyre pressure.
Tyre lettering and tyre type
Incorrect use of the spare wheel or temporary spare wheel can lead to a loss of control of
the vehicle, to collisions or other accidents and cause serious injuries.
•Never use a spare wheel or temporary spare wheel if it is damaged or worn down to the
tread wear indicators.
•Some vehicles may be equipped with a temporary spare wheel instead of a spare
wheel. The temporary spare wheel can be recognised by a sticker and the text 80 km/h
or 50 mph. This is the maximum speed at which you are permitted to drive with this
tyre. The sticker must remain in place throughout the wheel's service life.
•Never drive faster than 80 km/h (50 mph). Do not accelerate quickly, brake suddenly or
drive at high speed through bends.
•Never drive further than 200 km with a temporary spare wheel if it is fitted to the drive
axle.
•The temporary spare wheel should be exchanged for a normal wheel as soon as
possible. The temporary spare wheel is designed for a short period of use only.
•The temporary spare wheel must always be secured firmly with the wheel bolts
supplied by the factory.
•Never drive using more than one spare wheel that is a different size than the original
tyres.
•After fitting the temporary spare wheel, the tyre pressure must be checked as soon as
possible ⇒ Tyre pressure.
•Snow chains must not be used on the temporary spare wheel.
•Do not fit a temporary spare wheel to the rear axle when towing a trailer ⇒.
WARNING
The spare wheel is not fitted with a tyre pressure sensor. If the spare wheel is used with
tyre pressure sensor, the tyre monitoring system indicator lamp will flash in the instrument
cluster display after approximately ten minutes ⇒ Tyre monitoring systems.
NOTICE