See also:

Only refill the diesel exhaust fluid yourself in exceptional circumstances
To be able to reach the nearest service center with your vehicle, you may refill the diesel exhaust fluid yourself, making sure to heed the warning notices specified below. Handling diesel ex ...

Engine specifications
...

Switch off the engine during longer stops
Switch off the engine during longer stops, e.g., at traffic lights, railroad crossings or in traffic congestion. Fuel savings are achieved after the vehicle is switched off for only approx. 4 s ...