2016 Nissan NV will not start, seems electrical

What is your question?

I have a 2016 Nissan NV3500 with the 5.6L V8. The vehicle started sluggishly once, then died, acting like it got no gas when the pedal was held down. Replaced the battery. Battery is hot, the starter turns over vigorously - but nothing happens. Fuel pump doesn't hum when the key is turned. I see voltage to the coils. Disconnecting the intake and spraying starter fluid in, trying to crank - nothing. ODB2 connects, confirms power, then hangs forever - cannot communicate. I have tested every fuse five times - three by physically unplugging and inspecting, swapping them around. Twice with a voltage tester. I have replaced the crank position sensor. I have confirmed the wiring harness to the ECM is snug and locked in place. All I can figure at this point is that the ECM is bad or some wiring has gone bad elsewhere. Any ideas?

How long has your 2016 Nissan NV3500 had this problem?

a few days