Hello guy's. please share your opinion... I have volvo 2011 cumins engine isx 15 . Truck doing Regeneration completely . but DEF tank always full?????? How and why it maybe happens?!
Did you delete aftertreatment system, DPF, SCR? If an answer is "yes", than it is normal. I answer is "no", than it is not normal. I had situation After i have replaced DEF pump filter and cleaned aftertreatment system and cleaned the doser valve...everything came back to normal.
The float inside the DEF tank is sticking. You can pull it out and try to free it up (I've got it to work once or twice) or you'll have to replace the whole sending unit/heater.