Fuel injection amount learning process (diesel-powered vehicles)
To keep exhaust emissions and engine noise low, the engine very occasionally performs a learning process for the fuel injection amount.
The engine sounds slightly different from usual while the learning process is taking place. The change in the engine sound does not indicate a fault.
See also:
Boot lid (or tailgate)
WARNING
It is dangerous to drive with the boot lid (or tailgate) open since carbon
monoxide (CO) gas can enter the cabin.
You cannot see or smell CO. It can cause unconsciousness and even death.
...
Weatherstripping
To prevent freezing of the weatherstripping on the doors, bonnet, etc., they
should be treated with silicone grease. ...
On a snow-covered or frozen road
(1) When driving on a snow–covered or frozen road, it is recommended that you
use snow tyres or tyre chains. Refer to the “Snow tyres” and “Tyre chains” sections.
(2) Avoid high–speed ...