See also:

Headlamps fogged up on the inside
The headlamps may fog up on the inside if there is high atmospheric humidity. Drive with the headlamps switched on. The level of moisture diminishes, depending on the length of the journey and ...

Important safety notes
WARNING For safety reasons, switch off the windshield wipers and remove the key from the ignition lock before changing the wiper blades (vehicles with KEYLESS-GO: make sure that the on-board ...

High outside temperatures
If DEF heats up to over 122 °F (50 °C ) for extended periods, e.g. as a result of direct sunlight on the DEF reservoir, DEF can decompose. Ammonia vapors develop as a result. WARNING When o ...