Unexpected ICE startup?

Discussion in 'Prius Prime' started by Mark Miller, Mar 13, 2019.

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  1. Mark Miller

    Mark Miller New Member

    Half a dozen times this winter (Michigan) my 2017 Prime has started its engine within two miles of leaving home with a full charge. No defrost or climate control on, which will pretty much always start the ICE anyhow. At the next red light, I'll power off, wait a few seconds, and re-start, and I'm back in EV for the rest of my trip.

    This does not happen every time, and while it only started in winter, I can't say it is on the coldest days.

    Has this been discussed before, and any ideas? Not a major life problem, just slightly annoying.
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  3. Mark Miller

    Mark Miller New Member

    OK, so I found the thread "Prime in cold weather" from Jan 18, so this has been known for a while, if not completely understood. Still strange, in that it is intermittent, not recurring even when conditions are practically identical.
  4. nmcotwpv

    nmcotwpv New Member

    I have a long, fairly steep downhill section with a traffic light at the bottom not far from my home. I have found that if it is below about 40 degrees F, and I am forced to slow or stop because of the light, the engine turns on. There is another similar hill a few miles further in my morning commute, but stopping on it has caused the engine to turn on only once. My guess is that at the first hill, the battery is still cold and any strong charge or discharge event causes the computer to think it needs to use the engine, but normal driving will warm the battery so this is a problem only early in the drive.
  5. Same thing - Michigan - My 2018 Prius Prime started up the other day just as I pulled in the garage with 16% battery and 55 degrees out. After 23000 Miles I am at 70% ev.
    Not to worried I think the car just needed to run its engine.

  6. It's a cold weather thing. It took me a few years to get used to when the ice will seemingly randomly fire up, but after some time one starts to see the logic.
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  8. nmcotwpv

    nmcotwpv New Member

    I recently started using the scheduled recharge, with climate prep turned, so that if finishes recharging just before I leave in the morning. So far it seems that doing so prevents the engine on event, at least down to about 30F with an added boost of a slight increase in cold weather battery range. Too bad Toyota does not advertise this option more.

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