Sudden change in behavior ... 2008

It all just depends on how happy the car is with its temperature and the state of battery charge. All the behaviors you described happen sometimes. A Prius can be an interesting car to live with, but it knows what it's doing.

 

I suspect I won't be able to persuade you otherwise.

 

Did you turn off the heater or AC recently?

 

Typically the car starts the engine to warm it up briefly; this ensures the engine is ready to work instantly when called on. However if the engine is already warm and the hv battery has a good charge, then it may stay off until you accelerate or increase speed enough.

 

Are you using a block heater?

On our third gen, I'll sometimes plug in the block heater on ours for a couple of hours, if I need to move the car from garage to street, without starting up the engine, and don't relish doing it in 10 second "spurts". This reliably spoofs the car into allowing low-speed EV, thinking it's partially warmed.

 

if you have owned the car for a few years and this is completely new behavior, i would say there's probably something wrong.
if you purchased it more recently, and haven't experienced all the seasonal climate changes, i'd say there's probably nothing wrong.

 

a/c will drain the battery fast enough to start the engine fairly quickly. and even so, a completely warmed up engine will start as soon as you begin accelerating, regardless of a/c use.

 

It's a little less "organic" than that. The car's computers likely are programmed to fire up the engine, depending on accessories running, and ambient temp, and coolant temp.

And ultimately, all the electrical energy comes from the gas engine.

 

If it's so DRAMATIC then you need to give us some measurements? How many seconds goes by from pushing power button to before you hear engine starting? How many seconds do you consider normal? How many seconds do you consider abnormal... How do these numbers change based on weather temperature and engine temperature? With the heater on? With the AC on?

As in what you're describing doesn't have any substance without accurate observations and measurements, especially if you don't have any warning lights or MPG issues or other symptoms. I agree with your mechanic that you're trying to fix something that's not broken and you're overthinking this... And we love to overthink here on PriusChat, but if you want us to overthink with you we need way more data.

 

I'm sure we've experienced something like what you're experiencing but your description is lacking in specific details / lost in translation...

 

at least it's better and not worse. maybe your mpg's will go up

 

There is always the possibility Toyota has a slightly different control algorithm for Northern Europe. On the other hand we get guys who owned a car for ten years and never saw the flashing immobilizer light when shutdown.