This may be a ridiculous question but

[MonsterBilly]

is it just possible to pee in the DEF tank. I just purchased a container of DEF from autozone. It states that the ingredients are 62.5% water and 32.5% urea.

Why couldnt I just have a couple beers and fill the tank?

[mazsecond]

Unfortunately that would not work. Urine is an aqueous solution of greater than 95% water, with the remaining constituents, in order of decreasing concentration urea 9.3 g/L, chloride 1.87 g/L, sodium 1.17 g/L, potassium 0.750 g/L, creatinine 0.670 g/L and other dissolved ions, inorganic and organic compounds.

So basically, unless you have some sort of super piss I don't think it would work to well, sorry to kill your hopes