See also:

Mercedes-Benz M-Class Owners Manual
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Front fog lamps
Only vehicles with front fog lamps have the fog lamps function. WARNING If you suspect that driving conditions will be foggy, turn the light switch to before you start your journey. Otherwise ...

Fuel grade
You should only refuel with unleaded premium-grade gasoline as this avoids damaging the catalytic converter. If engine running problems are apparent, have the cause checked immediately and rep ...