Great information - thank you.
I drove into work today (only about ten miles). After being parked for approximately 15 minutes I went back to the car and opened the driver door. That self-test (or whatever) noise didn't occur. This matches my previous observation of it not occurring when the engine is warm. That is going to make it fun trying to duplicate at the dealer if I bring it in.
I'd be interested to hear if anyone else can duplicate this noise. It is barely noticeable when sitting in the car with doors closed in a quiet garage, but quite clear when looking down at the engine with the hood open (but again in a quiet garage). The sound recording I took does exaggerate the volume, and adds an echo effect. It occurs about once every nine seconds, and I'd say goes on for at least three minutes. This is the only mechanical noise being produced by the engine in this situation.
BTW (hijacking my own thread): The parking garage at work has very steep ramps and tight turns, but the DCT w/hill hold worked perfectly. Much easier than my old manual-transmission 2003 Focus. Did notice a bit of vibration through the accelerator pedal, but I believe that is expected sometimes when creeping along.
My vehicle: Stock 2013 Focus SE Hatchback w/auto