Patient is a 2007 Cooper S 105K. I went to start it this morning, and it cranked but didn't start.
Car sat over the weekend, but there was no prior indication of anything being wrong.
Battery seems good, and it has not thrown any codes (as it did previously when the starter had failed).
I suspect it to be one of the fuel pumps.

This evening, with the Bentley in hand I began diagnosing. Checked the fuel pump fuse, and that was good.
I pulled the rear seat bottom to get access to the tank fuel pump. Per the Bentley, I then pulled the fuel pump relay and jumped the socket with a 15amp fused jumper. No noise from the fuel pump in the tank. I believe I heard a click coming from under the hood, which I would assume to be the HPFP.

Next, I pulled the harness off the tank fuel pump and measured the voltage at pin 2 & 5 (blue/white & brown), with and without the relay jumped. Nada.

Bentley notes that if voltage and ground are present (which does not appear to be the case), the fuel pump is probably faulty.
If there is no voltage (does appear to be the case), check wiring between fuel pump and fuel pump relay. Not much else in the way of elaboration...

Anyone have suggestions as to what the problem might be or next steps? Common spot where the wiring gets fubar'd for the in-tank pump?

Looks like this has been touched on before, but no resolutions posted.
https://www.northamericanmotoring.co...ump-relay.html

I'll likely try directly applying 12V to the pump tomorrow on those two pins to verify that the pump is indeed good.