i thought you are a Russian.. I wrote no info about scr will get damaged or not if def will not be sprayed inside.
@Bpat first step that you need to do is to monitor all data values at SCR screen of DL. . hook up the DL and monitor the process. Drive the truck with hooked DL. Exhaust temp must be above 500f. monitor both nox sensor values. you may find something suspicious.. if you see negative values, then its time to change sensors.
Check and clean (or have a shop do it) the differential pressure sensor. Been seeing these little suckers cause major headaches for drivers.
The worst of your problems will come if you do not fix this. My 2012 Freightliner cascadia did the same thing and after spending over $21,000 the problem is still not fixed. You have been warned...
Ours is doing the same thing. But still running fine with no codes. Probably drove it 10k miles without def.
