Keeping Audio on while engine power is off

Keep the car in READY and put it in P. Do not turn it off. This "music when the car is off" is an American thing. The Prius was not designed for the American market originally. If you are the type that sits in the car for ages while parked like during a lunch break, or waiting for a partner to shop, or things like that, then just keep the car READY and in P. Anything else and you will deplete the very tiny lawn-mower sized 12v battery in the back. The Prius already automatically shuts the engine off when it isn't needed. So just let it do it's job.

 

Hi Les. What 2k1 Toaster says is correct. It's best to leave the Prius in "Ready Mode" if you want to listen to the audio for any period of time. In this mode the electrical power essentially comes from the big (hybrid) battery instead of the tiny 12V one, and as long as the aircond/heat is off then it will typically only run the engine briefly every 20 minutes or so.

There is a way however to listen to the audio with the "engine off" (not in ready mode), and that is to turn it off and then press the power button one time with your foot off the brake pedal. This is called accessories mode. In this mode you can use the radio, but personally I only recommend it if you want to listen for around 15 to 20 minutes or so. Any longer then it's best to just turn it on in the normal manner (press button with foot on the brake pedal) to ready mode. Also, if you do decide to use the "accessory mode", be careful to only press the power button once. If you press it twice in succession (with foot off the brake pedal) then it goes into "ignition on" mode. This is a diagnostic mode that drains the 12v battery a lot faster than accessory mode, so try to avoid that.

 

I 2nd all that. I recommand keep car in park and let engine on/off when required automatically. Keeping ACC mode will have weird behavior as 12V battery drains fast.

 

If it's the same as 3rd gen, you would push the start button once, with your foot off the gas. I think. I say "I think", because I NEVER do this: the 12 volt battery is so diminutive, just doesn't have the reserve.

A traditional keyed car, when you turn the key one click towards off, would put you in this mode, engine off but radio still powered. The Prius: push the start button to shut off, it shuts completely off, and you have to restart (as describe above), to get to that radio only mode.

I would also never sit with the car, completely on, listening to the radio, basically because I hate wasting gas, pulling my mpg down, lol.

 

Just be aware with the car in ready sitting there with your very old hybrid battery it will go deep into purple bars which is pretty depleted. Keep an eye on the battery meter on the mfd. just be aware with the battery in purple or possibly red you will have very poor power when you drive away so take it assy don’t just floor it as the tiny little motor will have to power the car by itself which is hard to do when you demand power when none is available.
There’s no free ride. When the car is on it’s using battery power. When the battery gets low it turns the engine on.

Last year my 07 bought new with 100k miles would go to purple in a drive through. Getting very tired next stop is battery rebuild. I bought a battery charger and using a discharge/ charge it really woke it up. No more purple 100 % better. Ymmv.

Your car is new to you and may have a very tired hybrid battery. Keep an eye on it see where it’s at.
It may have been sold because the hybrid battery is tired.