I got my low DEF warning last week at 4625 miles. Dealer refilled it at no cost, said that tanks were empty (or near empty) and that transfer pump is working properly. Possible result of previous DEF repair at same dealership at 1000 miles... unclogging of crystalized DEF in valve... Possible that the tanks were not properly refilled at that time, but this was just a guess on the part of the SA. Cincinnati, OH.
2011 BMW 335d, Space Grey/Black, Sport, Premium, Cold Weather, Convenience, Nav, Harman Kardon/Sat, iPod
2010 Audi A4 2.0 Quattro P+ 6MT (Wife's car)
2004 BMW R1150RA