03-Blue-Powerstroke
New member
My "500 mile to empty" light just came on for the DEF in my truck today. I filled it up at 5500, 13K, 20K and now at 23K it thinks it needs it again. I did not do any towing in the last 3K miles so what causes it to use it so fast? I drive 50 miles a day all highway too and do not let it idle. I was stuck in traffic the other day for about an hour, would that cause it to use so much?