2014 No power to fuel pump

A few months back my 2014 would crank but not start. After some basic troubleshooting, I determined that I wasn't getting any fuel pressure. At that point the fuel pump and fuel ECU were replaced, and the issue was resolved and the truck had been fine for the last few months.

3 days ago, the same thing happened, although after waiting 5 minutes and trying again, it started. This morning its dead, same situation, cranks, but won't start. I pulled off the fuel line again and cranked it and sure enough no fuel pressure.

Assuming that the pump didn't die a crib death, I have been looking over the wiring diagrams and looks at this from an electrical perspective. The FP relay in the fuse box tested ok, and I swapped it with another one to as well to verify. Next thing I wanted to check is the COPN relay, but I'm confused if there is one on the 2014. The spot that the C/OPN relay is supposed to occupy is empty on my fuse panel. Am I looking at this wrong??

In the wiring diagram, the C/OPN relay is clearly listed, but is it located elsewhere in the 2014?

 

So I spent the better part of the day on the ground testing all of this out. Tested from the relays and fuses all the way to the pump itself. As it turns out some mice or a rat decided to munch on the harness from the fuel ECU on the frame rail to the fuel pump itself. One of the power wires to the pump was seriously compromised, but it was still enough to get the truck operating for a while. Without dropping the tank to get to the part of the harness that runs on top/inside of the crossmember, I would have never seen this.

I fixed up the harness and the truck fired right up.

 

Nice work! You definitely started looking in the right spot. In my experience relays fail by rarely. Making sure all fuses are good is the first step.

Finding broken or damaged wiring in/under the truck is never fun nor easy. Did the wire show signs or rubbing or chaffing or are you 100% sure some kind of rodent was eating it?

 

It was definitely rodent damage, the loom was chewed up over a 3 inch run and the area it was in was floating up inside the cross member.