See also:

Cleaning the steering wheel and gear or selector lever
Thoroughly wipe with a damp cloth or use leather care agents that have been recommended and approved by Mercedes- Benz. ...

The spray nozzles are misaligned
The windshield washer fluid from the spray nozzles no longer hits the center of the windshield. The spray nozzles are misaligned. Have the spray nozzles adjusted at a qualified specialist work ...

Locking the vehicle (mechanical key)
If the vehicle can no longer be locked with the SmartKey, use the mechanical key. Open the driver's door. Close the front-passenger door, the rear doors and the trunk lid. Press the locking ...