Page 26 of 245

24Keys, doors and windows
1. Unclip the cover using ascrewdriver in the cutout.
2. Remove the cover.
3. Extract the flat battery from its location.
4. Replace battery. Use CR 1620 or equivalent battery. Pay attentionto the installation position.
5. Clip the cover in place.
Fault
If the central locking system cannot
be operated with the radio remote
control, the cause may be one of the
following:
● Fault in radio remote control.● The range is exceeded.
● The battery voltage is too low.
● Frequent, repeated operation of the radio remote control while not
in range, which will require re-
synchronisation.
● Overload of the central locking system by operating at frequent
intervals, the power supply is
interrupted for a short time.
● Interference from higher-power radio waves from other sources.
Manual unlocking 3 25.Electronic key system
Enables a keyless operation of the
following functions:
● central locking system 3 25
● ignition switching on and starting the engine 3 131
The electronic key simply needs to be on the driver's person.
Additionally, the electronic key
includes the functionality of the radio
remote control 3 23.
Handle with care, protect from
moisture and high temperatures and
avoid unnecessary operation.
Page 27 of 245

Keys, doors and windows25Replacing battery in electronic
key
Replace the battery as soon as the
system no longer operates properly or the range is reduced. The need for battery replacement is indicated by a
message in the Driver Information
Centre 3 98.
Batteries do not belong in household
waste. They must be disposed of at
an appropriate recycling collection
point.
1. Unclip the cover using a screwdriver in the cutout.
2. Remove the cover.
3. Extract the flat battery from its location.
4. Replace battery. Use CR 2032 or equivalent battery. Pay attention
to the installation position.
5. Clip the cover in place.
Fault
If the central locking cannot be
operated or the engine cannot be
started, the cause may be one of the
following:
● Fault in electronic key.
● Electronic key is out of reception range.
● The battery voltage is too low.
● Overload of the central locking system by operating at frequent
intervals, the power supply is
interrupted for a short time.
● Interference from higher-power radio waves from other sources.
To rectify the cause of the fault,
change the position of the electronic
key.
Manual unlocking 3 25.
Central locking system Unlocks and locks doors, load
compartment and fuel filler flap.
Pull an interior door handle fully to
unlock and open the respective door.
Page 240 of 245

238IndexAAccessories and vehicle modifications .......................... 175
Adaptive forward lighting ...........109
AdBlue .................................. 90, 137
Adjustable air vents ...................124
Advanced parking assist ............154
Airbag and belt tensioners ...........87
Airbag deactivation ................56, 88
Airbag label................................... 52 Airbag system .............................. 52
Air conditioning regular operation ................................ 126
Air conditioning system .............. 116
Air intake .................................... 125
Air vents...................................... 124
Antilock brake system ................ 144
Antilock brake system (ABS) .......89
Anti-theft alarm system ................33
Anti-theft locking system .............. 32
Appearance care ........................211
Armrest ................................... 47, 48
Ashtrays ....................................... 79
Automatic anti-dazzle ..................37
Automatic light control ...............108
Automatic locking ........................29
Automatic transmission .............140
Autostop ............................... 91, 132
Auxiliary heater ........................... 123B
Battery discharge protection ......114
Battery voltage ............................. 99
Belts.............................................. 49
BlueInjection ............................... 137
Bonnet ....................................... 177
Brake and clutch fluid .................215
Brake and clutch system .............89
Brake assist ............................... 145
Brake fluid .................................. 180
Brakes ............................... 144, 180
Breakdown.................................. 209
Bulb replacement ....................... 183
C Capacities .................................. 228
Catalytic converter .....................137
Central locking system ................25
Centre console lighting ..............114
Centre console storage ...............65
Changing tyre and wheel size ...199
Charging system .......................... 88
Child locks ................................... 30
Child restraint installation locations ................................... 61
Child restraints.............................. 58
Child restraint systems ................58
Climate control ............................. 16
Climate control systems .............115
Clock............................................. 78