Page 111 of 245
Lighting109Battery discharge protection
Vehicle battery state of charge
function
The function guarantees longest
vehicle battery life via a generator with controllable power output and
optimised power distribution.
To prevent discharge of the vehicle
battery when driving, the following
systems are reduced automatically in two stages and finally switched off:
● auxiliary heater
● heated rear window and heated mirrors
● heated seats
● fan
In the second stage, a message
which confirms the activation of the
vehicle battery discharge protection
will be displayed in the Driver
Information Centre.Switching off interior lights
To prevent discharge of the vehicle
battery when the ignition is switched off, some interior lights are switched
off automatically after some time.
Page 129 of 245

Driving and operating127During an Autostop, the heating and
brake performance will be
maintained.
Conditions for an Autostop
The stop-start system checks if each
of the following conditions is fulfilled.
● The stop-start system is not manually deactivated.
● The driver's door is closed or the driver's seat belt is fastened.
● The vehicle battery is sufficiently charged and in good condition.
● The engine is warmed up.
● The engine coolant temperature is not too high.
● The engine exhaust temperature is not too high, e.g. after driving
with high engine load.
● The ambient temperature is not too low or too high.
● The climate control system allows an Autostop.
● The brake vacuum is sufficient.● The self-cleaning function of the exhaust filter is not active.
● The vehicle was driven at least at
walking speed since the last
Autostop.
Otherwise an Autostop will be
inhibited.
Notice
The Autostop may be inhibited for
several hours after a battery
replacement or reconnection.
Certain settings of the climate control
system may inhibit an Autostop. See
Climate control chapter for more
details 3 111.
If an autostop is temporarily not
available, D flashes green 3 87.
Immediately after driving at a higher
speed an Autostop may be inhibited.
Vehicle battery discharge protection
To ensure reliable engine restarts,
several vehicle battery discharge
protection features are implemented
as part of the stop-start system.Power saving measures
During an Autostop, several electrical
features such as auxiliary electric
heater or rear window heating are
disabled or switched to a power
saving mode. The fan speed of the
climate control system is reduced to
save power.
Restart of the engine by the driver
Vehicles with manual transmission
Depress the clutch pedal without depressing the brake pedal to restart
the engine.
Vehicles with automatic transmission The engine is restarted if
● the brake pedal is released while
the selector lever is in position D
or M
● or the brake pedal is released or the selector lever is in position N
when the selector lever is moved
to position D or M
● or the selector lever is moved to position R.
Page 240 of 245

238IndexAAccessories and vehicle modifications .......................... 174
Active emergency braking ....88, 147
AdBlue .......................... 86, 130, 229
Adjustable air vents ...................119
Advanced parking assist ............153
Airbag and belt tensioners ...........83
Airbag deactivation ................54, 83
Airbag label................................... 49 Airbag system .............................. 49
Air conditioning regular operation ................................ 120
Air conditioning system .............. 111
Air intake .................................... 120
Air vents...................................... 119
Antilock brake system ................ 137
Antilock brake system (ABS) .......85
Anti-theft alarm system ................31
Anti-theft locking system .............. 30 Appearance care ........................211
Armrest ............................. 44, 45, 62
Ashtrays ....................................... 76
Automatic anti-dazzle ..................35
Automatic crash notification (ACN) 99
Automatic light control ...............102
Automatic locking ........................28
Automatic transmission .............133
Autostop ............................... 87, 126
Auxiliary heater ........................... 118B
Battery discharge protection ......109
Belts.............................................. 46
BlueInjection ............................... 130
Bonnet ....................................... 176
Brake and clutch system .............84
Brake assist ............................... 138
Brake fluid .......................... 179, 219
Brake light................................... 186
Brakes ............................... 137, 179
Breakdown.................................. 209
Bulb replacement ....................... 182
C Capacities .................................. 229
Catalytic converter .....................130
Central locking system ................23
Centre console lighting ..............108
Centre console storage ...............62
Changing tyre and wheel size ...199
Charging system .......................... 83
Child locks ................................... 28
Child restraint installation locations ................................... 58
Child restraints.............................. 55
Child restraint systems ................55
Cigarette lighter ........................... 76
Climate control ............................. 15
Climate control systems .............110
Clock............................................. 74