NHTSA Complaint #11495697 — 2017 CHEVROLET SILVERADO 2500

When transiting between airport and home in very remote area in subzero temps the DEF warning system suddenly came on limiting vehicle speed progressively. No services were available both at this time of day and in this very remote area. There needs to be some way to override this system in the case of potential life and death. There were no warnings that this system was going to activate, it simply came on. The system had plenty of fluid but it appears the DEF heater failed. A vehicle should have an override for life and safety matters. Vehicle is going to a diesel mechanic for service now.