Repost from Reddit; and then a question

Discussion in 'Gen 5 Prius Technical Discussion' started by Paul Gregory, Jul 19, 2025 at 9:43 PM.

  1. Paul Gregory

    Paul Gregory Senior Member

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    Be careful putting your Prius in neutral!
    Well, I got a Prius Prime 2021 a few months ago, and was definitely the idiot driver today trying to put my Prius in neutral at the automatic car wash today.

    First time at one of these car washes, but it seemed pretty obvious I could see the car in front of me go in neutral and get pulled along. So I rolled up hoping I'd feel the tow engage, and all would be good.

    I thought I'd put my car in neutral, but it seemed to be moving too fast. Fortunately I hit the breaks before slamming into the car in front of me.

    Then, per the exasperated employee's instruction, I put the car in reverse to reengage the tow, and once again nearly slammed into the car behind me, twice. The employee at the wash kept telling me what I already knew, put it in neutral, foot off the break, and let it go.

    Finally, we both realized, I was not in neutral. Each time I'd attempted to put the car in neutral, I wasn't holding the shifter in position for long enough for neutral to engage (it takes like 3 seconds).

    Just a warning to all you Prius owners out there. I was able to narrowly avoid several accidents, but it was a very embarrassing experience all around and hope no one else will have this experience.

    I assume this is some sort of safely mechanism to prevent drivers from accidentally putting the vehicle in neutral when shifting to drive or reverse. But for anyone used to a standard transmission this feels like a very unintuitive design, if I pull the shifter straight out and release it should go into neutral no matter what.

    Love everything else about the car so far though, so I suppose there will always be drawbacks with any car.

    Question: If it was truly going into neutral (not just freewheeling the transmission) Why should it do anything but simply disengage all power from the wheels? That 3 second delay and sudden lurch cast doubt on that theory. And here's the curious part: suppose the gas engine is running at 2000 RPM while you shift into neutral, Wouldn't there have to be a similar amount of reverse rotation of the electric drive motor? How could this happen without some active monitoring and control of the drive wheels?

    Perhaps the car in the posting had no active control over the drive wheels when shifting to neutral, but my experience in car washes and elsewhere has been that there is no lurching at all. In either my gen 3 or my gen 5.
     
  2. ChapmanF

    ChapmanF Senior Member

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    This appears to have been the source: archived Reddit post

    You've posted questions about neutral at length in other threads, and repeated some of them here, but conveniently for this thread, no more than the first seven words of your question are needed to answer it.

    As a quick review of the reposted reddit post confirms: the car was not going into neutral. Not 'truly' going into neutral, not falsely going into neutral, not in any other way going into neutral. You move the shifter left and hold it to select neutral, and the driver didn't do that, so neutral wasn't selected.

    Here's that text again.

    The car went forward in the first paragraph, because it had already been in D, and then the driver didn't select N, so the car was in D, and went forward.

    The car went backward in the second paragraph because the driver had shifted to R "to reengage the tow", and then didn't select N, so the car was in R, and went backward.

    Finally, in the third paragraph, they remembered how to select N, and when they did that, the car rolled freely with the tow just like yours or mine does in N.


    For what it's worth, I think the Reddit poster exaggerated the length of time you need to hold the shifter left to select N. I have never put a stopwatch on it, but I think it is much closer to 1 second than 3.

    Amusingly, the exact wording in my 2010 owners' manual is Keep the shift lever in "N" for a while after you shift it to that position.

    So now we know the precise answer: a while.
     
    #2 ChapmanF, Jul 19, 2025 at 10:28 PM
    Last edited: Jul 19, 2025 at 10:45 PM
  3. Paul Gregory

    Paul Gregory Senior Member

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    Of course this brings out the trolls who are here to obfuscate the issue and create conflict.
    Never mind trying to engage the topic, just deny and ignore the important points to prolong the conflict.
    After all, conflict is their only goal.

    But for those who want to engage this topic in good faith, here it is: If "neutral" were just simply freewheeling of the transmission, there would be a rather noticeable "bump" in the drivetrain when the wheels have to bring the idle transmission geartrain up to speed very quickly (and in reverse). I have shifted to neutral many times, and never felt any sort of a lurch or a bump, even when traveling at speed. This would not be possible of the laws of physics are still in effect. There must be an interval where the traction control computer operates the electric motors to achieve a smooth syncing of the two power sources with the wheels. My car has never made any noticeable bumps or lurches. This convinces me that the computer is actively engaged, not just "freewheeling the transmission."
     
  4. ChapmanF

    ChapmanF Senior Member

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    It would be great for a few readers who have come this far to comment on whether post #2 or post #3 seems more on-topic to explain the story the Reddit poster told.
     
  5. Paul Gregory

    Paul Gregory Senior Member

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    If you were earnestly trying to deal with this issue, you'd address the facts of it, instead of constantly trying to dismiss and deny them.