service emissions message

[trbankii]

^^ That would be my guess.

A 32.5% solution of DEF will begin to crystallize and freeze at 12 deg F (-11 deg C). At 32.5%, both the urea and water will freeze at the same rate, ensuring that as it thaws, the fluid does not become diluted, or over concentrated. The freezing and unthawing of DEF will not cause degradation of the product.

[rapidoxidationman]

For all of us DMax owners who are Pre-Urea: What does the truck do to keep the DEF from freezing?

Also, "unthawing" is freezing...

[DmaxMaverick]

For all of us DMax owners who are Pre-Urea: What does the truck do to keep the DEF from freezing?

Also, "unthawing" is freezing...

They have a pump/heat unit in the tank. Heater failure isn't uncommon. I know of several DEF heater failures in all classes, passenger car to HD truck. The heater in our 2014 Cruze Diesel failed at about 35K. The good news is, they are covered under warranty for a long time/miles, and aren't that expensive or difficult to repair if not.