Is this normal??

I haven't noticed either in mine. Sorry

 

There'll be a noticeable whine while decelerating, especially when you're braking as well. This is the transaxle changing from it's electrical motor function to being a generator. That'll only be as you're slowing though.

It seems unusual to hear it surge above idle when stopped. Actually, once the car is decently warmed the engine should immediately shut down at stops.

I'd reluctantly suggest you ask the dealership. Slightly less reluctantly: bring it up at the first service interval, if you're going with dealership service.

 

I never noticed a whine while decelerating. The engine may rev up while you are stopped and the HV (traction) battery requires charging. Maybe the HV battery is faulty?

 

If this is reproducible, I'd suggest demonstrating it to your dealer and have it checked out. I have never has my ICE surge as you describe.

 

I've had rpm shoot up with a previous Civic Hybrid. Stopped at a red light, the engine rpm started climbing, went past 3000 (the car has a tach). Had it in drive and had to really stand on the brake. Dropped back down after about 10~15 seconds. Freaky as hell.

My guess would be buggy software, or some sticking sensor/valve.

 

I have a Gen II Prius and it has the same issue. Form my commute I have to go down a steep hill followed by a signal light. The battery gets overcharged while going down the hill. I believe Prius does this to improve gas mileage. If I get a green light at the bottom of the hill, Prius runs normal. If I get a red light, Prius engine demonstrates the unusual behavior you have described. I believe it thinks that the extra stored energy is not going to be used up soon so it tries to discharge the battery to bring it into the recommended zone.

Here is more precisely what the Prius does. After a few seconds the engine will suddenly rev up really high. Then after a couple of seconds the engine will shut down. This cycle will repeat until it thinks the battery has been sufficiently discharged. This process can go on for a very long time depending on the condition of the battery.

Initially I would be terrified whenever this happened. Now I am used to it and don't give it a second thought. I am surprised that other users have not seen this issue.

 

i haven't noticed it in my last 3 prius, but perhaps the 16 is different. any chance of capturing it on your phone?

 

The Prius goes thru different warm-up stages which are well documented for prior gens. Somewhere around stage4 after you come to full stop it goes to stage5, or whatever just from memory. Until you hit the final stage of warm up, the engine will stay on when you come to a stop. Now then, none of these stage transitions is normally accompanied by unusual noises or racing engine. You can use OBDII reader to track things like radiator temp to see when the stages are changing.

 

Pull up the energy distribution display and watch it next warm up cycle if you are at a stop light, I've seen mine keep the engine running indicating it is charging the traction battery, then heard a slight change in motor/generator pitch, the engine RPM changed slightly, but the engine continued to run. The traction battery SOC was near full. The engine continued to run until the light turned green, presumably to complete engine (coolant and cat/emissions) warm up cycle. This is my first hybrid and it makes all kinds of 'strange' noises, but nothing I haven't been able to figure out what it was after hearing it a few times.

As others stated, if you can reproduce the noise at will, take it back to the dealer and demonstrate it to them if you're concerned.

 

Mine makes a slight noise on initial start up. Seems a little noisier than the Gen 3 for that one item but good so far.

 

There are a host of quirky Prius operational things. After having a gen 2 for 10 years, I'd say the gen 4 does all the same things, just a bit smother. Actually the low speed wine is new in the gen 4. Either it's the noise maker I read about or the motors running up to a faster speed than they did in the previous versions. When the batteries are low and your in park the ICE will startup and rock the car a bit forward, kind of scary. The brakes will release when your braking and hit a bump. The Gen 4 is much better. There is a bit more dance in the braking, when I think the battery is full. But it's all normal, get used to it. IMO still a great car, that has gotten better.

 

I know exactly what you're talking about, because I hear it from mine. I only hear it at lower speeds, with the windows down, on a quiet street...maybe up to about 25 mph, because at higher speeds the wind and road noise drowns it out. I notice it whenever the engine is on, under those conditions I described. It's kind of like a whistle that changes pitch in odd ways that aren't totally consistent with road speed or engine load.

I chalk it up to some weird airflow quirk in the air intake. I'm not worried about it.