After purchasing my 2012 Express Van with the Duramax, I did much research online. I had a P2BAD code popped up. It was a Nox Sensor. My van was out just out of the five year warranty so the dealer lightened me of $750.00.
So, I joined a couple of forums that related to the van and the Duramax. I am concerned with ULSD Fuel. While it's less than 5% of all the Duramax's out there, if the CP4 pump decides to 'explode' get ready to write a $10,000.00 check.
So what to do? Convert to back to a CP3 Pump? $1,800.00. Nah. Lube! While it appears that soybean bio fuel is the best, Opti Lube XLP is the next best thing. I can't find any bio diesel near me, I ordered some XLP. I ordered an Opti Box with the 8 oz bottles and a gallon refill with pump.
I tried some in my work van which is a 2007 Duramax van chassis (without DEF of course). I plan to start using it regularly in my Duramax Yoder Toter. I hope I stay out of the Duramax rebuild business.