Mercedes-Benz 2011 E-Class Sedan Operator's Manual page 168

Refueling
166
Problems with the fuel and fuel tank
Problem
Fuel is leaking from the
vehicle.
The fuel filler flap
cannot be opened.
Possible causes/consequences and M Solutions
G
Risk of explosion or fire
The fuel line or the fuel tank is defective.
X
Turn the key to position 0(
immediately and remove it.
X
Do not restart the engine under any circumstances.
X
Consult a qualified specialist workshop.
The fuel filler flap is not unlocked.
or
The key batteries are discharged.
X
Unlock the vehicle using the mechanical key (
X
Open the trunk lid or the tailgate.
X
Manually unlock the fuel filler flap using the emergency release
( Y page 164).
Y page 149) in the ignition lock
Y page 79).