See also:

Important safety notes
WARNING Severe conditions (e.g. strong air pollution) may require replacement of the filter before its scheduled replacement interval. A clogged filter will reduce the air volume to the interi ...

Low outside temperatures
DEF freezes at a temperature of approximately 12 °F (–11 °C). The vehicle is equipped with a DEF preheating system when it leaves the factory. Winter operation is therefore also guaranteed at ...

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 ...