See also:

Service and literature
Your vehicle is covered under the terms of the warranties printed in the Service and Warranty Information booklet. Your authorized Mercedes-Benz Center will exchange or repair any defective parts ...

Activation conditions
You can activate the HOLD function if: Rthe vehicle is stationary. Rthe engine is running. Rthe driver's door is closed or if your seat belt is fastened. Rthe electric parking brake is released. ...

Heavy and light loads
WARNING Depressing the brake pedal constantly results in excessive and premature wear to the brake pads. It may also cause the brakes to overheat, seriously impairing their effectiveness. ...