ATTENTION! all Hymotion owners!

I have a 2008 Prius (with a Hymotion system). I usually avoid the "screen-flip" issue by avoiding gasoline use altogether.

I don't have any special mods or hacks installed. All I have is a normal Prius with a normal Hymotion system installed.

By carefully timing when I turn on my Hymotion switch, I can prevent the ICE from starting at all. I've noticed that I never get any screen-flip if my ICE has not run since starting the car.

In situations where I've been driving above 34 mph (with the ICE on), I've noticed that the screen-flip sometimes starts when I drop below 34 mph. Sometimes, it doesn't.

The screen-flip is just a symptom of something worse. If your screen is flipping, you probably aren't in EV mode. Unless you do something to stop the screen-flip, it will continue and you will continue to be unable to enter EV mode.

I've found that there are two simple ways to stop the screen-flip and get into EV mode. The simplest way is to speed back up (if traffic and speed limits permit) over 34 mph and then slow back down again. This almost always works. The second time you drop below 34, the car will almost always go into EV mode and do no screen-flip. I've made a habit of slowing down well before I get to the 30-mph speed zone so that I can see what my car is going to do and have room to briefly speed back up again, if necessary.

The other way (if speeding up is not an option) is to simply pull over and restart the car. On the second try, the car usually goes directly into EV mode with no screen-flip (even if you let the engine start up briefly).

If you know someone who has a mod/hack that prevents the screen flip, you might suggest that they offer to sell it to Hymotion/A123.

I've talked to the people at A123 about the screen-flip issue. They don't know why it happens and they don't have a way to fix it.

Arthur

 

It seems that the Hymotion bugs start showing-up after a while.......

 

Hmmm... That's interesting.

I have a 2008 Prius and I have always (from day 1) been able to avoid the screen flip by starting the car with the ICE off and keeping the ICE off (what I call "cold EV mode").

Even in "warm EV mode," I can get rid of the screen-flipping behavior by doing the things described in my previous post.

When I drive up my hill in "screen-flipping mode" (with the ICE running) I get this weird behavior where the ICE kicks off for about a second. This occurs about every 7 seconds.

I asked Hymotion why the engine keeps kicking off while going uphill at high RPM. They sent me a data logger to record what was happening. When I sent it back, they told me that it was normal behavior. They said that the Hymotion system was designed to operate that way. If it doesn't go into EV mode when you first drop below 34 mph, it will keep trying to get into EV mode, even if you're going up a steep hill. The screen-flipping seems to have something to do with those continual attempts to enter EV mode.

I asked them why it sometimes goes into EV mode and sometimes starts screen-flipping instead. They eventually acknowledged that they have observed this same behavior and don't know what the trigger is. They said that it must have something to do with the Prius system not being ready to enter EV mode at that moment, but they didn't know the specific reason that the Prius system is not ready for EV mode.

They said that they had noticed that re-starting the car often gets rid of the screen-flipping and allows them to enter EV mode, but that's all they were able to tell me.

I later discovered that speeding back up above 34 and then slowing down again will usually reset things and get you into EV mode with no screen-flipping.

Have you noticed whether you are actually in EV mode or not (when the screen-flipping occurs)? I know you have mentioned before that you use a manual switch to get into EV mode instead of relying on the Hymotion system to get you into EV mode.

Perhaps that's why you haven't noticed a correlation between screen-flipping and an inability to get into EV mode. Perhaps your manual EV mode switch is actually CAUSING the screen-flipping.

When you say that "it affects all units," what do you mean? I don't think that everybody has this problem all the time. I think most people are like me in that it is a problem that can occur most of the time, depending on how they drive.

Most people probably don't pay too much attention to whether they are in EV mode or not at any given moment. I think a lot of people could get much better mileage if they understood their system's behavior a little better.

For the past 90 days, I've averaged well over 150 MPG. (See my post on the other thread.) I've been very stubborn and have figured out numerous tricks to stay in EV mode more and get higher MPG.

Arthur