We just bought a brand new 2009 Prius 8 days ago and have put only 500 miles on the car. We went out to the car today and the keyless entry would not work and and the car would not ulock, so I used the key to gain entry and when I got in the car it would not start. The check engine light flashed every time I pushed the power button. We left the car there and came back in an an hour and it started and drove fine. Any ideas of what might be going on? This does not inspire a lot of confidence in Toyota, the car is a WEEK OLD!!!
Simplest explanation: somebody drained the 12V battery. The possibilities get less likely and more expensive from there. Make certain that all lights are off and the car is locked every time you park it, at home also.
If you agree with Richard that the 12V battery may have been drained inadvertently (or maybe it was not sufficiently charged before you took delivery) then leave the car READY for several hours to give the battery a chance to charge up. It is not necessary to actually drive the car during this period (unless you want to.)
Any recharging happens only when the car is READY. Perhaps ambient temps warmed up later in the day so the 12V battery may have had a bit more power then. Here is a brief overview of how the batteries interact: The traction battery provides high voltage (nominal rating 201.6VDC) to the DC/DC converter when the car is READY. The output of the converter is a regulated 13.8VDC. Since the 12V battery is attached to the 12V bus, it will charge up when the car is READY as 13.8V is available at that time. The traction battery state-of-charge is continually monitored by an ECU dedicated to this task and located within the traction battery enclosure. When the traction battery needs to be recharged, the gasoline engine will turn on and spin MG1. AC voltage from MG1 goes through the inverter and becomes DC (voltage around 220-230V or so) which charges the traction battery.