Freightliner Cascadia 2013 DEF code 3364 spin ee61

Hello everyone,

I have a 2013 freightliner cascadia with 270K miles.. i recently did a force regen on the truck. I pushed the regen button to see if it would kick in & it did. I went to sleep woke up and found a solid yellow engine light & error code EE61 SPIN 3364. I’ve had the truck for about 2 years, never had it go under 1/2 tank of def until recently. I filled it all the way up 3/18 the same day. My radiator ended up going out on 3/19, picked it up from the shop on 3/22. 3/23 did the regen and solid yellow engine light. I read it’s poor def, what should I do, drain it out and pour in fresh clean BLUE, or burn it off and top it off with fresh def? Any suggestions? Thanks