On the glass dash of a IH45 there is a gauge that is labeled SCR. What does SCR stand for?
Urea tanks on diesel trucks -- that's the law in the United States starting... (https://www.eurekalert.org/pub_releases/2008-11/i-uto111008.php)
The gauge was saying 99. So do you think it was telling the quantity of DEF was 99% full?
Probably, on mine can change tanks from gal to percentage. 99 gal would be a real big def tank.