Tis a shame GM decided not to put a level indicator on the DEF reservoir. :/ am sure I read somewhere a % level is obtainable thru a scan tool(tec2 etc) but not 100% on this. Have considered fabbing up a dipstick to be able to randomly check the level, but again, with the possibility of contamination(which shows up on the DIC as poor quality DEF fluid) am yet to give it a shot. Ideally it would be a length of plastic, similar to whats found in between yella-tung flooring. currently using a brand known as Nonox, which states not to allow contact with any metal as cross contamination occurs.
Come on GM, give us an update for the DIC for the DEF level!!!