See also:

Problems with the SmartKey
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Numerous stowage facilities, high degree of variability and temperature-controlled cup holder
Numerous, easily accessible stowage facilities in the M-Class can accommodate bottles, mugs, keys, coins and much more. Each of the four doors can also easily accommodate a large 1-litre bottle. ...

Refrigerant of the air-conditioning system
The air-conditioning system is filled with R134a refrigerant and a special PAG lubricant. Never use refrigerant R 12 (CFC) or mineral lubricants. Otherwise, you could damage the air-condition ...