I had a transfer pump problem and it did in fact trigger an SES. But I think some people have had problems with the transfer pump and got no SES. I took the car in because of the SES, not because of getting to the point of low on DEF where as I recall some of the other people took theirs in because of low DEF lights. Now of course this is not to say those others really had no pump issues at all and the dealer simply said they did to cover their initial mistake of not topping off the tanks completely. The cars inability to show some sort of level on these tanks is one of my bigger complaints with the design of things but I am not sure if any car/truck using DEF has a tank level sending unit for such a purpose.