Page 307 of 498

305 Operation
At the gas station
At the gas station
Refueling
The fuel filler flap is located on the 
right-hand side of the vehicle towards the 
rear. Locking/unlocking the vehicle with 
the SmartKey or the SmartKey with 
KEYLESS-GO* automatically locks/un-
locks the fuel filler flap.1To open the fuel filler flap
2To insert the fuel filler cap
Turn the engine off
by turning the SmartKey to 
position0. Remove the SmartKey 
from the starter switch. 
by pressing the KEYLESS-GO* 
start/stop button. Open the driv-
er’s door (with driver’s door open, 
starter switch is now in position0, 
same as with SmartKey removed 
from starter switch).
Open the fuel filler flap by pushing at 
the point indicated by the arrow 1.
The fuel filler flap springs open.
Turn fuel cap counterclockwise and 
hold on to it until possible pressure is 
released.
Take off cap and set it in direction of 
arrow 2 in the recess on the fuel filler 
flap.
To prevent fuel vapors from escaping 
into open air, fully insert filler nozzle 
unit.
Only fill your tank until the filler nozzle 
unit cuts out – do not top up or 
overfill.
Warning!
G
Gasoline is highly flammable and poisonous. 
It burns violently and can cause serious inju-
ry. Whenever you are around gasoline, avoid 
inhaling fumes and skin contact, extinguish 
all smoking materials. Never allow sparks, 
flame or smoking materials near gasoline!
Failure to remove the fuel cap slowly could 
result in personal injury.
 
     
        
        Page 308 of 498
306 OperationAt the gas station
Replace fuel cap by turning it 
clockwise.
You will hear when the fuel cap is 
tightened.
Close fuel filler flap.Warning!
G
Overfilling of the fuel tank may create 
pressure in the system which could cause a 
gas discharge. This could cause the gas to 
spray back out when removing the fuel 
pump nozzle, which could cause personal 
injury.
iOnly use premium unleaded gasoline 
with a minimum Posted Octane Rating 
of 91  (average of 96 RON / 86 MON).
Information on gasoline quality can 
normally be found on the fuel pump.
For more information on gasoline, see 
“Premium unleaded gasoline” 
(page 450) or the Factory Approved 
Service Products pamphlet.
iLeaving the engine running and the fuel 
cap open can cause theú malfunc-
tion indicator lamp (USA only) or 
the± malfunction indicator lamp 
(Canada only) to illuminate.
More information can be found in the 
“Practical hints” section (
page 356).
 
     
        
        Page 472 of 498

470 IndexF
Fahrenheit
Setting temperature units 149
Fastening the seat belts 43
Fine adjustment
Cruise control 259
First aid kit 389
Flat tire 412
Collapsible tire 
(CLK 55 AMG only) 394
Lowering the vehicle 418
Minispare wheel 
(except CLK 55 AMG) 393
Mounting the spare wheel 413
Preparing the vehicle 412
Flexible Service System (Canada vehicles) 
see Maintenance service system
Flexible Service System (FSS) 456
Floormats*
Removing 278
Installing 278Fog lamp, rear 128, 405
Fog lamps
Replacing bulbs 404
Fog lamps, front
Messages in display 382
Replacing bulbs 405
Switching on 128
Front air bags 65
Front lamps
Messages in display 382–384
Replacing bulbs 404, 406
Switching on 124
Front passenger front 
air bag off indicator lamp 77, 360
Front seat head restraints
Installing 114
Power seat 114
Removing 114
Front seats
Seat heating* 119
Ventilation* 120
FSS (Canada vehicles) see 
Maintenance service system
FSS (Flexible Service System) 456Fuel 306
Additives 451
Fuel reserve warning lamp 359
Gasoline additives 451
Premium 
unleaded gasoline 306, 448, 450
Requirements 451
Reserve warning 25
Technical data 447
Fuel additives 451
Fuel cap
Message in display 356
Fuel consumption statistics
After start 161
Since last reset 161
Fuel filler flap 305
Locking 305
Opening 399
Unlocking 305
Fuel requirements 451
Fuel reserve tank
Message in display 381
Fuel tank
Capacity 448
Filler flap 305