If it won't reset that could mean you have other issues.
Before I went any farther I'd pull the fuel filters and have a look.
Look for gunk and stuff in the lower one, make sure the drain does drain.
Top filter take it out and look at the fiter for metal shavings. Shine a light in the fuel bowl. What do you see? If you see rust or metal then you have big problems..don't start the motor. Have it towed in for a fuel system flush.
08F250 CC 6.4 PSD
Banks 6 gun/ram air
40' Stoneridge 5th wheel, coming in at 15.4K.