Working on a friends tail light problem. Get it fixed and the next day he starts for home and gets white smoke  missing then dies. I am thinking the connector to the rear and also fuel pump in tank could be problem. This morning changed the fuel filter. Cracked the fuel line at the VP and hit the key. Tank in pump ran with pressure and fuel squirting from loose fitting. Has had eng light on for 6 months. Checked code using key sw. Got only P 1693 then P end code. Nothing else. Did it again got same thing?? I have a code reader. will it do any better?  This is a farm truck running farm diesel from a bulk tank. No gauges! 3 prior VPs. Maybe 70,000 on this one. 475,000 on truck. I do not think working on lighting has anything to do with the present problem.  ANY THOUGHTS??

The key trick only reads one computer in some years. The 1693 is telling there is another code in the other computer. Hook your code reader up and see what it says.

Yep, hook up the other reader. 

Hate to say it, but it sounds like a VP issue.

If he has gone through that many VP's he may want to look at a new lift pump and fuel pressure gauge MINIMUM. He has some issues going on.

Yea. i asked him when does he change fuel filters and he says  " when it gets hard to start". Got to love them farmers.  It is a 4wd desert truck with no rust. Needs a lot of TLC. I think his dad is going to give him his old 2013 with 130k on it. 

Put a reader on it this AM.  First it says there are 2 codes set, I go to read codes and it says there are no codes set. ?? About confusing as the P1693 and no other codes come up. I am pretty sure the vp is bad. The loom going to the rear of the truck had an intermitent open in the ground circuit. The ground i think also grounds the transfer pump in the tank. No ground no fuel! He says at times for the past 6 months the tail and turns would all flash together. That means no ground. Still do not know why no code is thrown.

Problem solved.  When the transfer pump was not getting power( no ground)  The truck was run completely out of fuel. No codes?  What does a farmer do? Crank on it till something happens. Sure enough he cranked it till fuel got to the injectors and away it went. Why did i not think of something this simple and crack some lines?