Drove the car to work yesterday, made a few stops along the way with no issues.
When I got out of the office, the car would no longer crank.
I have a CEL, but no DTC (checked with HP Tuners). No security light. Battery is good (checked with a multimeter while someone else tried to start - dropped from 12.2V to 11.9V).
Scanner can talk to the ECM, all accessories work. I can hear the fuel pump and starter relay clicking. The starter is about a month old and has, at no point, given any indication of suboptimal performance.
About a week ago, I had a similar issue, but it turned out to be a blown 30A fuse. I replaced that and everything was fine. I pulled and checked all of the fuses and everything looks fine.
When viewing the status bits in my scanner, I can see that the clutch position switch is working. I also see a crank request when trying to start the car.
Earlier today, it slowly cranked for about half a second, then stopped. Haven't been able to repeat that.
Good times. I have the factory service manual set but haven't found a useful diagnostic procedure (though I'm probably just looking in the wrong place.)