Page 109 of 247
Lighting107Battery 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 128 of 247

126Driving and operatingDuring 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 3 109.
If an autostop is temporarily not
available, D flashes green 3 86.
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 242 of 247

240IndexAAccessories and vehicle modifications .......................... 172
Active emergency braking ....87, 145
AdBlue .......................... 85, 129, 227
Adjustable air vents ...................117
Advanced parking assist ............152
Airbag and belt tensioners ...........82
Airbag deactivation ................54, 82
Airbag label................................... 49 Airbag system .............................. 49
Air conditioning regular operation ................................ 118
Air conditioning system .............. 109
Air intake .................................... 118
Air vents...................................... 117
Antilock brake system ................ 136
Antilock brake system (ABS) .......83
Anti-theft alarm system ................31
Anti-theft locking system .............. 30 Appearance care ........................208
Armrest ............................. 44, 45, 62
Ashtrays ....................................... 76
Automatic anti-dazzle ..................35
Automatic crash notification (ACN) 97
Automatic light control ...............100
Automatic locking ........................28
Automatic transmission .............132
Autostop ............................... 86, 125
Auxiliary heater ........................... 116B
Battery discharge protection ......107
Belts.............................................. 46
BlueInjection ............................... 129
Bonnet ....................................... 174
Brake and clutch system .............83
Brake assist ............................... 137
Brake fluid .......................... 177, 217
Brake light................................... 183
Brakes ............................... 136, 177
Breakdown.................................. 206
Bulb replacement ....................... 180
C Capacities .................................. 227
Catalytic converter .....................129
Central locking system ................23
Centre console lighting ..............106
Centre console storage ...............62
Changing tyre and wheel size ...196
Charging system .......................... 82
Child locks ................................... 28
Child restraint installation locations ................................... 58
Child restraints.............................. 55
Child restraint systems ................55
Cigarette lighter ........................... 76
Climate control ............................. 15
Climate control systems .............108
Clock............................................. 74