Originally Posted by
DIESELWRKS
so you go a warning telling you DEF was low or out of def? not sure on your year but the newer ones there are a few warnings you get before you get put in limp mode. did you get those? so on only tanks that have never been cleaned and have higher miles. the tanks do crystalize over time. Have seen bottoms of the tanks glazed over bad enough that you now have lost some capacity. now that I know this info , if you let me know if it went into limp mode without prior low DEF warning . I will reach out to a bud and see if I can find a DIY reset. or if a scan tool is needed.