Welp grab onto your ankles and ask the shop to use lube because your in for a world of hurt and trouble is what it means. Could be one of a number of things or a symptom of a dozen others. Best case is you got some crap def and draining your tank and refilling or putting in some good def will fix it. Worst case is a wild goose chase fixing a cascade failure of crap.
Start with the cheap options. Drain and replace. If it doesnt clear up its likely a sensor has gone bad. 1# culprit is the quality sensor in the tank. #2 is one or both NoX sensors. #3 is the def doser could be acting up. If you idle a lot or havent done it recently it could also be a clogged EGR. If none of the above....good luck hope it doesnt turn into a 55k repair job like my pete had to track down the issue.
I used to get that code, soon after refilling the tank.
I was told not to top the tank off (try to keep cramming the fluid in after the pump clicks off).
Since I stopped doing that, I haven’t seen the code since.