See also:

Checking the coolant level
Only check the coolant level when the vehicle is on a level surface and the engine has cooled down. Turn the SmartKey to position 2 in the ignition lock. On vehicles with KEYLESS-GO, press th ...

System self-test
After you have switched on the ignition, the system carries out a self-diagnosis. WARNING A malfunction in the system has been detected if one of the following conditions occurs:  - ...

Cleaning the exterior lighting
  Clean the plastic lenses of the exterior lights with a wet sponge and a mild cleaning agent, e.g. Mercedes-Benz car shampoo or cleaning cloths. Only use cleaning agents or cleaning ...