Using the rear center seat belt
If the left-hand rear seat backrest is folded down and back up again, the rear center seat belt may lock. The seat belt can then not be pulled out.
To release the rear center seat belt:pull out the seat belt by the belt outlet on the backrest approximately 1 in (25 mm) and release it again.
The seat belt is retracted and released.
See also:
Problems with the SmartKey
Problem
Possible causes/consequences and
Solutions
You cannot lock or unlock the vehicle using
the SmartKey.
The SmartKey battery is discharged or nearly discharged.
...
Notes on technical data
The data stated here
specifically refers to
a vehicle with standard equipment. Consult
an authorized Mercedes-Benz Center for
the data for all vehicle variants and trim
levels. ...
Driving with summer tires
At temperatures below 45 °F (+7 °C), the
elasticity of summer tires and therefore also
traction and braking capability are reduced
considerably — equip your vehicle with
M+S tires. Using summe ...