I have my car in at the dealer today, and they just called me with the verdict. According to the code, it was a relay that had intermittent failures. Apparently there is a TSB for this affecting mostly 13s and early 14s (like mine), although I could not find it in the sticky thread. The TSB calls for changing 5 relays because water/condensation can get into them in cold weather, which they did (even though only one was failing for me). The girl told me I was lucky it had not happened before, as last year they were getting calls for that almost every day. Some people even had to have their car towed because they could not get it to start.
They told me the brake pedal switch causes a different code to be logged, so they ruled that out.
I'm driving an almost brand new 3 today (less than 600 miles). It's ok but I was expecting a bit more "oomf" in response to the gas pedal, considering the lower weight of the car. Can't wait to get my CX-5 back!
Prolly the 2.0L engine, it moves a 3 pretty well actually but the torque peak is higher in RPM than the 2.5 so it has less of that off-the-line pull unless you really push it.