Total Loss of Power!

I had just pulled into a parking lot and was coasting to a stop at very low speed and my 2009 Prius (only 50k on the ODO) lost total power - engine off and all lights on the dash also off. I did not notice any warning lights.

As I pulled into the parking lot and I thought I heard a strange hissing noise. Although at the time I thought this noise was coming from outside and did not consider it to be from my car (my radio was on at the time so that didn't help). However within 10 seconds of noticing this noise the car powered off.

After a few more seconds, I hit the power button and the car started up as if nothing had happened. The noise was no longer apparent. Ironically, I was visiting Harbor Freight to purchase a hollow hole punch for the smelly vent tube fix. Anyway, I parked and checked under the hood for any obvious issues. First checked the drive belt which was still on, then checked the oil which was all good, then checked for any obvious coolant leaks which I could not see.

After running into Harbor Freight for 5 minutes, I drove home (approx 6 miles) and experienced no issues with the car. At home, I plugged in my bluetooth OBD2 and the Torque lite app showed zero logged or pending fault codes in the ECU. In addition, I checked the 12V battery via the vehicle display. The battery appeared to be good - 13.9V when the car was fully powered on.

The one weird thing i have noticed about the car is that there is a buzzing noise (different from the brake vac pump noise) after I power off the vehicle after driving. The noise originates from the drivers side under the hood and last about 10 seconds - although sometimes it seems to last much longer. It was my understanding that this noise is normal for a Prius?

Between the funky smell and this new issue, I'm starting to regret my purchase....I've only had the car for a few weeks! Any help is greatly appreciated.

 

Yeah, as far as I know all recalls have been performed. After I purchased the vehicle, I had it serviced at the dealership - they changed the oil, transmission fluid, and performed two recalls - the Steering intermediate extension shaft and the electric water pump. I'll definitely check if they skipped any recalls.

 

Could failure of the combination meter be accompanied by a hissing type noise? After the power loss, I recall hitting the power button and the vehicle powered back on. Your description of the combo meter problem seems to imply that this would not be possible as the vehicle would not have actually powered off - so hitting the power should have powered it off if it was actually still on?

 

Just to clarify, the hissing noise I heard as I pulled into the parking lot was not the same as the buzzing noise I always hear after powering off the car. This sound was more of a high pitched whirring sound - although since I initially thought the noise was not from my car, I wasn't paying too much attention to it.

 

Yeah, car has a clean title and clean carfax - it was purchased privately from the original owner. I did not get the sense that he was hiding anything.

 

Could this issue be related to the replaced coolant pump? What about some type of smartkey failure?