›Open the battery cover in the direction of the arrow 1 or press the interlock on
the side of the battery cover in the direction of the arrow 2 » Fig. 163 , fold the
cover up and remove.
The battery cover is installed in reverse order.
The edge of the polyester battery cover is inserted between the battery and theside wall of the battery cover when working on the battery.
Checking the battery electrolyte level
Fig. 164
Vehicle battery: Electrolyte level
indicator
First read and observe the introductory information and safety warn-
ings on page 207.
On vehicles with a vehicle battery fitted with a colour indicator » Fig. 164 , the
electrolyte level can be determined by looking at the change in colour.
Air bubbles can influence the colour of the indicator. For this reason carefullyknock on the indicator before carrying out the check.
› Black colour - electrolyte level is correct.
› Colourless or light yellow colour - electrolyte level too low, the battery must be
replaced.
Vehicles with a START-STOP system are fitted with a battery control unit for checking the energy level for recurring engine start.
We recommend that you have the acid level checked regularly by a specialist ga-
rage, especially in the following cases.
› High external temperatures.
› Longer day trips.
› After each charge.
Winter time
The vehicle battery only has a proportion of the starting power in lower tempera- tures. A discharged vehicle battery may already freeze at temperatures just be-
low 0 °C .
We therefore recommend that you have the battery checked and, if necessary, re-
charged by a specialist garage before the start of the winter.
CAUTION
For technical reasons, on vehicles with the description “AGM”, the electrolyte lev- el cannot be checked.
Note
The battery acid level is also checked regularly by a specialist garage as part of
the inspection service.
Charging
First read and observe the introductory information and safety warn-ings
on page 207.
A properly charged vehicle battery is essential for reliably starting the engine.
›
Switch off the ignition and all of the electrical components.
›
Only when performing a “quick-charge”, disconnect both battery cables (first
“negative”, then “positive”).
›
Attach the terminal clamps of the charger to the battery terminals (red = “posi- tive”, black = “negative”).
›
Plug the mains cable of the charger into the power socket and switch on thedevice.
›
After charging has been successful: Switch off the charger and remove the
mains cable from the power socket.
›
Only then disconnect the charger's terminal clamps.
›
Reconnect the cables to the battery (first “positive”, then “negative”).
It is not necessary to disconnect the cables of the battery if you recharge the ve-
hicle battery using low amperages (for example from a mini-charger). Refer to the
instructions of the charger manufacturer .
A charging current of 0.1 multiple of the total vehicle battery capacity (or lower) must be used until full charging is achieved.
209Inspecting and replenishing
It is necessary to disconnect both cables before charging the battery with high
amperages, known as “ rapid charging”.
The vent plugs of the vehicle battery should not be opened for charging.WARNING“Quick-charging” the vehicle battery is dangerous and requires a special
charger and specialist knowledge.
CAUTION
On vehicles with the START/STOP system, the pole terminal of the charger must
not be connected directly to the negative terminal of the vehicle battery, but only
to the engine earth » page 228, Jump-starting in vehicles with the START-STOP
system .
Note
We therefore recommend that vehicle batteries be rapid charged by a specialist
garage.
Replacing
First read and observe the introductory information and safety warn-
ings
on page 207.
The new vehicle battery must have the same capacity, voltage, current and the
same size as the original Battery. Suitable vehicle battery types can be purchased
from a specialist garage.
We recommend having the battery replaced by a specialist garage, where the
new vehicle battery will be installed properly and the original battery will be dis-
posed of in accordance with national regulations.
Disconnecting and reconnecting
First read and observe the introductory information and safety warn-
ings
on page 207.
On disconnecting and reconnecting the vehicle battery, the following functions
are initially deactivated or are no longer able to operate fault-free.
OperationOperating measureElectrical power window (operational faults)» page 44Panoramic sliding roof (operational faults)» page 234Enter the radio/navigation system code num-
ber» User manual of the radio
or » user manual of the naviga-
tion systemSetting the clock» page 13Data in the multifunction display are deleted.» page 25
Note
We recommend having the vehicle checked by a specialist garage in order to en-
sure full functionality of all electrical systems.
Automatic load deactivation
First read and observe the introductory information and safety warn-ings
on page 207.
The vehicle voltage control unit automatically prevents the battery from discharg-
ing when the battery is put under high levels of strain. This manifests itself by the
following.
› The idling speed is raised to allow the generator to deliver more electricity to
the electrical system.
› Where necessary, large convenience consumers such as seat heaters and rear
window heaters have their power limited or are shut off completely in the event
of an emergency.
CAUTION
■ Despite such intervention by the vehicle electric system management, the vehi-
cle battery may be drained. For example, when the ignition is switched on a long
time with the engine turned off or the side or parking lights are turned on during longer parking.■
Consumers that are supplied via a 12-V power socket can cause the vehicle bat-
tery to discharge when the ignition is switched off.
210General Maintenance
WARNING■A discharged vehicle battery may already freeze at temperatures just below
0 °C. If the battery is frozen, do not carry out a jump start with the battery of another vehicle – risk of explosion!■
Pay attention to the warning instructions relating to working in the engine
compartment » page 199.
■
The non-insulated parts of the terminal clamps must never touch each other
– risk of short circuit!
■
The jump-start cable connected to the positive terminal of the battery must
not come into contact with electrically conducting parts of the vehicle – risk of
short circuit!
■
Do not clamp the jump-start cable to the negative terminal of the dis-
charged battery. There is the risk of detonating gas seeping out the battery
being ignited by the strong spark which results from the engine being started.
■
Route the jump-start cables so that they cannot be caught by any rotating
parts in the engine compartment.
■
Do not bend over the battery – risk of caustic burns!
■
The vent screws of the battery cells must be tightened firmly.
■
Keep any sources of ignition (naked flame, smouldering cigarettes, etc.)
away from the battery – risk of explosion!
■
Never jump-start vehicle batteries with an electrolyte level that is too low –
risk of explosion and caustic burns.
CAUTION
■ There must not be any contact between the two vehicles otherwise current
may flow as soon as the negative terminals are connected.■
The discharged battery must be properly connected to the system of the vehi-
cle.
■
We recommend you buy jump-start cables from a car battery specialist.
Jump-starting using the battery from another vehicleFig. 179
Jump-starting: A – flat battery, B
– battery providing current
First read and observe the introductory information and safety warn-
ings on page 226.
The battery of another vehicle can be used to jump-start your vehicle if the en-
gine will not start because the battery is flat. Jump-start cables are required for
this purpose.
The jump-start cables must be attached in the following sequence.
›
Attach clamp
1
to the positive terminal of the discharged battery
A
» Fig. 179 .
›
Attach clamp
2
to the positive terminal of the battery supplying power
B
.
›
Attach clamp
3
to the negative terminal of the battery supplying power
B
.
›
Attach the clamp
4
to a solid metal part which is connected firmly to the en-
gine block or to the engine block itself.
Starting engine
›
Start the engine on the vehicle providing the power and allow it to idle.
›
Start the engine of the vehicle with the discharged battery.
›
If the engine does not start, terminate the attempt to start the engine after 10 seconds and wait for 30 seconds before repeating the process.
›
Disconnect the cables in exactly the reverse order
to the one described above.
Both batteries must have a rated voltage of 12 V. The capacity (Ah) of the battery
supplying the power must not be significantly less than the capacity of the dis-
charged battery in your vehicle.
Jump-start cables
Only use jump-start cables which have an adequately large cross-section and in-
sulated terminal clamps. Observe the instructions of the jumper lead manufactur-
er.
Positive cable - colour coding in the majority of cases is red.
227Emergency equipment and self-help
Temporary spare wheel216
the rear seats fold down seat backrest and fold seat fully for- ward
68
Tiptronic127
Tools220
TOP TETHER181
Towing228
Towing a trailer152
Towing device Description
152
Drawbar load152
Use and care156
Towing eye front
229
Rear229
Towing protection40
Traction Control System (TCS)137
Trailer152, 156
13-pin power socket157
driving with a trailer157
loading156
Safety eye157
Trailer stabilisation158
Transport Luggage compartment
81
Roof rack system90
Transporting children safely177
TSA158
Turn signal49
Turn signal system Warning light
21
Two-way radio systems100
Type plate244
Tyre inflation pressure Warning light
21
Tyre load-bearing capacity see Wheels
214
Tyre pressure monitor Setting
215
Tyre repairCheck pressure226
Preparations225
Sealing and inflating the tyre226
Tyres212
Inflation pressure213
New214
See Wheels214
Sizes213
Tyre wear indicator213
U
Underbody protection
192
Unleaded petrol135
Unlocking Individual settings
36
KESSY35
Key33
Remote control34
Vehicle key33
Unlocking and locking32
Useful equipment 12-volt power outlet
75
Ashtray74
Car park ticket holder71
Cigarette lighter74
Clothes hook79
Cupholders73
Removable ski bag81
Storage compartment under the front armrest76
Using the information system23
Using the selector lever127
Using the variable loading floor with a spare wheel
90
V
Variable loading floor
88
Removing and fitting carrier rails89
Variable loading floor with spare wheel Removable storage box87
Vehicle battery Automatic load deactivation
210
charging209
Checking the battery electrolyte level209
Cover208
Operation in winter209
Replacing210
Safety instructions207
Vehicle care182
Alcantara194
Artificial leather194
Cloths194
Vehicle Condition See Auto Check Control
13
Vehicle data sticker244
Vehicle dimensions245
Vehicle key Locking
33
Unlocking33
Vehicle tool kit220
vest holder for reflective vest
219
Visibility55
Visors see Sun visors
55
W
Warning at excessive speeds
28
Warning lights14
warning messages Diesel particulate filter
20
Warning symbols see Warning lights
14
Warning triangle219
Warranty5
259Index