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Cruise Control Quirk ?

Discussion in 'Gen 3 Prius Technical Discussion' started by JOLLIMON, Jun 11, 2019.

  1. JOLLIMON

    JOLLIMON Junior Member

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    Morning All, new to the Prius world, just bought a 2014 Trim 2. I've noticed that when I set the cruise control to 55 and at some point have to hit the brakes, when I use the resume feature it increments my speed by 1Mph. Is this just some odd quirk with the Prius, as I've never observed it in any other vehicle I've owned. Thanx in advance.
     
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  2. ASRDogman

    ASRDogman Senior Member

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    If you'll notice, when you raise or lower the speed one press on the arm, you may not get a full mile.
    It will depend on where the speed is, (55.2 or 55.8). I "think" it may do 3/4 of a mph. I also noticed
    the it is different depending on my speed. I cannot speak for others, but that's how mine works.
     
  3. Pluggo

    Pluggo Senior Member

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    Of course you are just briefly pushing RES/ACC button and not holding it long enough for ACC to kick in, right? Of course. That said, and in addition to the good advice, above, bear in mind that most any cruise control will have the tendency to temporarily go over the setting as you crest a hill, and briefly lose speed at the bottom or when a hill abruptly begins.
     
  4. JOLLIMON

    JOLLIMON Junior Member

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    Yup, just briefly hitting the resume to re-engage cruise and it will kick me up 1 MPH, not a big deal was just curious if this was a quirk particular to the Prius
     
  5. StarCaller

    StarCaller Senior Member

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    it's the other way round here: when I resume cruise control, I usually end up with 1 mph lower than before /
    always /
     
  6. Grit

    Grit Senior Member

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    Here’s a wrench to throw in; if driving against wind, my resume mph is always 1mph higher than it was set. Driving with the wind, resume sets 1mph lower.

    But obd2 apps has the correct mph displayed when resume.
     
  7. JOLLIMON

    JOLLIMON Junior Member

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    Gonna have to check that, I have a tailwind in the morning and headwind in the evening. Not something I considered.
     
  8. AzWxGuy

    AzWxGuy Weather Guy

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    I've always seen that, independent of wind direction (although now I'll pay attention to it), and in fact my finger does a decrement after I resume just to keep things square. Another interesting thing I've noticed about speed. I manage to drive through three radar speed indicators on my daily commute and my speedometer speed is always 1 mph higher than the detected speed. I remember someone else pointing that out in another thread.
     
  9. CR94

    CR94 Senior Member

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    Car speedometers almost always exaggerate, unless someone has installed larger tires than OE. I don't think my cruise control does the unintended increment thing. It has plenty of other annoying habits, though.
     
  10. Maarten28

    Maarten28 Active Member

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    Do you mean the cruisecontrol setpoint is 1 mph higher or does the car go 1 mph faster thant the setpoint?
    I've never seen the first, I've seen my car do the second a lot of times. Keeping speed is not accurate within less than a mph (km/h for me).

    Strange, in my car (in km/h) 10 clicks up in speed is 16 km/h, so I always assumed one click higher is 1.6 km/h (or 1 mph).
     
  11. ASRDogman

    ASRDogman Senior Member

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    mmmm?? Maybe one press of the lever up or down is .6 mph(1kph).
    That's why it doesn't always move 1mph up or down.

    Food for thought! :)
     
  12. CR94

    CR94 Senior Member

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    That's approximately what I see, if my presses are quick. It does not seem consistent.
     
  13. ASRDogman

    ASRDogman Senior Member

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    I've just adjusted to it. I've been in so many cars and used so many cruise controls, it's not worth trying
    to fix something that is not really broken. :)
    Mine is just a bite slow to respond. If it doesn't do it fast enough, I use the pedal, reset to a higher speed and
    start going down until I get where I want. Which tends to increase the MPG. :)
     
  14. JOLLIMON

    JOLLIMON Junior Member

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    Exactly, its as though I've hit resume twice, once to re-engage the cruise and then hit it again to increment up 1 mph, when in actuality only hit it once to re-engage, Not a real problem, just a bit odd.
     
  15. CR94

    CR94 Senior Member

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    Do you "hit" just momentarily, or hold the lever there for a second or so? If you are not quick, perhaps it treats what you are doing as two hits?
     
  16. JOLLIMON

    JOLLIMON Junior Member

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    Just a quick blip
     
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