Push "Park" Button, Then Engine Shuts Off

Probably just just that the engine was ready to shut off anyway.

 

^^^ Yep.

The only time I'd be worried is if the READY light goes out upon pressing Park. That would be abnormal.

There are many other cases where the engine will shut off, even while you're moving. You will likely be totally unaware of it (while moving) unless you monitor engine RPM via something that plugs into the OBD2 port like ScanGaugeII : Linear Logic - Home of the ScanGauge.

 

The question I would ask is why you pressed the park button.

 

Actually, it makes sence that the ICE would shut down after you push the Park button (assuming that it is at normal operating temp). You just told the car you aren't planning on moving.

 

obviously, you haven't owned this car since '07.

 

Yes. The engine is supposed to turn off in many cases when below 42 mph, including 0 mph. As I said, you may not be able to tell when it's on/off when moving.

Also, if you're light on the brakes, you'll be regen-ing back into the HV battery, instead of using friction brakes (where braking energy is lost as useless heat and brake dust). It's not uncommon for Priuses to go 100K miles on still be on the original brakes. I'm a tad short of 70K miles and still on the originals.

 

the engine may turn on or off at any time. that's normal, it has a mind of it's own.

 

Welcome to the group.

There is a reason why the Prius can attain 50+ mpg without much trouble. If you search you'll find lots of info about how Hybrid Synergy Drive works.

Soon you'll be thinking how wasteful it is that a conventional vehicle's motor will continue to run for no good reason, for example when the car is at a stop light.

 

Yep. There's a LOT to learn, if you wish to learn it.

Hybrid Vehicle | TOYOTA MOTOR CORPORATION GLOBAL WEBSITE gives a brief overview. The engine may also run to provide cabin heat (see Why mileage gets worse in winter | PriusChat under "Better heater management". You'll again need a tool like ScanGauge in order to monitor engine coolant temperature.

And yes, I second Patrick's post. I hate driving non-hybrid cars now. It's so stupid that an engine must uselessly run when idling/stopped. It's stupid that when braking on a conventional car, all the car's kinetic energy is lost as useless heat and brake dust, instead of it being partly recaptured to be repurposed for later use.

BTW, since it seems you're new to the Prius, if the 12 volt battery hasn't been changed, it's possible it needs to be replaced soon.

Please run the test at Weird stuff happening? MPGs dropping? Test The Battery | PriusChat after the car has sat MANY hours or overnight. Please tell us the 3 values (not just 1). Don't go changing the battery first until you tell us the values...

If you have HIDs, you can avoid unnecessary cycles on the lights by toggling between off and parking light positions.

Weird stuff can start happening w/a low or bad 12 volt. Don't waste $ on having a dealer "test" the 12 volt (07 Prius Dead - Any Guesses? | PriusChat).

And BTW, the 12 volt does NOT start the engine on the Prius. It's started by the big (HV) battery. Prius also has no dedicated starter motor nor an alternator.

If you ever need to jump the Prius, be absolutely sure to observe the correct polarity. If you reverse the polarity, you may damage the inverter, which has a 4 digit price tag.