I had my cam shaft sensor break off. From the description it may be the issue. FCA did cover it under warranty. They were shocked to see that the sensor had just broken off. They will have to remove the transmission to get to it.
I have a 2015 with the DEF gauge stuck at 1/4 tank. Getting the CEL and 500 mile fill warning. Took it to dealer and was told they have to replace the tank, pump and internal sensor for $2600 uuuuggggh... I got with Chrysler customer support and they were no help. Truck has 91k miles on it. Torn...