This dag on Cummins isx 15 code1921 dpf full

[Nhramember]

Ok good morning everyone. I have been going thru it with this motor. It’s got 984000 on it. Most recently replaced 6 injector and the fuel pump head. Now the emission system is giving me code 1921. I have tried to regenerate the motor . It starts then halfway thru stops temps get about 700degrees then quits. I have an open emissions campaign to do from Cummins free. What could be causing this? Is def full? It’s saying 0.00 ash load. I also replace dpf sensor yesterday. I’m stumped. Thanks everyone.