Is this a normal noise for EV mode?

No that doesn't sound normal to me. My Prime doesn't make that noise. If you take it to the dealer to have it checked out, have a service advisor go for a short ride with you so you duplicate the sound and they hear it so they can't come back to you and say they couldn't duplicate it. If they say it's normal, try another dealer.

 

take someone for a ride with you. sometimes new car owners hear things that aren't there. if they don't hear it, the service tech probably won't either.

 

Any chance you can record it with your phone sitting on the passenger seat, and upload it for us to hear?

 

Yes, but different in a way also. I had a non-plugin Prius for 14 years and there was a high frequency whine when driving the mile or so in EV mode. When I got my 2023 Prius Prime, I expected there would be times I heard that high freq whine. Turns out it is a different frequency, and while it is actually quieter than my old Prius, it was quite noticeable at first.

 

what's curious is that the op had a 17 prime and didn't notice anything.

 

Or just enjoy the sound of pure electric driving without the ICE noise. My wife calls our Prime a “space mobile”, and that whine is obviously the noise a “space mobile” makes.

 

The electric whine is quite different from what I'm used to from years of Gen 2 driving - the difference will primarily be that the electric motor is much higher RPM and lower torque - it's geared down so it spins 3 times faster. Difference is going to be less noticeable for people coming from a Gen 3, and it's basically the same as the Gen 4. Max electric (MG2) speed is 6,500rpm in Gen 2, 13,500rpm in Gen 3, 17,000rpm in Gen 4/5.

 

It could be the high pressure fuel pump and direct injectors turning on and off. Gen 4 only had port injection so you wouldn't hear any of that. The D4S that Toyota uses can use either port or direct fuel injection separately or under certain circumstances have both running at the same time.

 

there's a sandy munro video where he and his wife swear the radio is on in the bz4x they are test driving.
but they can only hear it when moving.

 

I transitioned from 17 Prime Advanced to 23 Prime SE - I too have noticed the increase in
noise level from the 17 to 23. Noise doesn't linger long but enough to be audible. If you have
your radio or music loud then sound can be easily missed.
I was just thinking they made the 23 noiser so pedestrians can hear the car coming and not so much
a faulty car. The 17 was super quiet and pedestrians were even surprised a car was behind them.
I definitely need to pay more attention as to when sound was occurring.

 

the pedestrian warning system shuts off at 15mph. it could be louder on the 23, depending on what volume levels might have been allowed previously.
easy enough to roll down the window and have a listen

 

2023 pedestrian warning sound shuts off at 23 mph, and has some logic about how loud it is played by speed

 

I have heard that sound when the a/c is on. Very faint but there when I first turn on the a/c.