Adblue Tank issue / Additive Tank issue / Urea light / emmisions fault

[notsofast]

The biggest issue is the shelf life of Adblue fluid, it is only 12 months from manufacture and after that it is very likely to crystallize. Therefore if you only do a few thousand miles a year, it will crystalize in the tank.

And of course, nobody gives out this information when you buy the new vehicle!