Cruise control out of control

Discussion in 'Prime Technical Discussion' started by mysacramento, May 14, 2022 at 1:22 AM.

  1. mysacramento

    mysacramento New Member

    Joined:
    May 28, 2021
    8
    3
    0
    Location:
    sacramento
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    Hello,
    the cruise control in my Prius Prime 2021 I don’t think it’s programmed correctly.
    When resuming to the set speed causes very abrupt acceleration. Why? Not very efficient and i would say dangerous too
    Very strange behavior , maybe it’s just my car doing that snd I should bring it to the dealer?
     
  2. schja01

    schja01 One of very few in Chicagoland

    Joined:
    Apr 22, 2005
    1,574
    1,059
    0
    Location:
    Chicagoland
    Vehicle:
    2018 Prius
    Model:
    Prime Advanced
    What Drive Mode? Eco, Normal, Pwr?
     
  3. vvillovv

    vvillovv Senior Member

    Joined:
    Mar 19, 2013
    2,464
    886
    1
    Location:
    NY
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    There are two types of Cruise (Dynamic Radar and Regular Cruise) Dynamic has some strange behaviors compared to Regular Cruise. Hold the Cruise Control On - Off switch for 5 seconds to activate the Regular Cruise Control. If the Prime still accelerates to fast for your liking when using resume, you can always use the Go Pedal to accelerate closer to your set speed before hitting the resume lever.
     
    FuelMiser likes this.
  4. mysacramento

    mysacramento New Member

    Joined:
    May 28, 2021
    8
    3
    0
    Location:
    sacramento
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    In eco mode, i didn’t try other modes. Dynamic cc, I didn’t know there is also a regular one.
    Regardless, it’s not working right in my opinion, I used to own a Sienna with dynamic cc and was working fine, on my Prime 10 years later, they made it worse, why accelerate so fast? all the gas saving up to that point is gone.
    Is there an effective way to notify Toyota directly about this?
     
  5. Mendel Leisk

    Mendel Leisk Cloud Watcher

    Joined:
    Oct 17, 2010
    46,995
    33,526
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    That seems to be industry-wide. I suspect if they made it more leisurely someone else would be complaining "what's taking so long".

    It bugs me too; there's something inherently unnerving, when a car accelerates all by itself. My work around, is to rarely if ever use "resume". Instead I'll just accelerate manually, then tap set again. Or hit resume when I've almost got to my previous target speed.
     
    fuzzy1 and Salamander_King like this.
  6. BiomedO1

    BiomedO1 Active Member

    Joined:
    Mar 27, 2021
    321
    177
    0
    Location:
    SacTown, Ca
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    IMHO; that's normal behavior. I use dynamic cruise, and usually set it for 68 mph - if the car in front of you is traveling <55 mph; your dynamic cruise will automatically slow your car to 55 mph, with whatever spacing you've programmed. Once the car in front of you clears; your car will accelerate back to it's set speed. I don't know of any way of trimming the rate of acceleration; other than disengaging the cruse control.. Your problem is probably compounded by not adjusting the trailing distance and using it in heavy traffic.

    It's a dumb computer that's doing what you told it to do; Not what you want it to do...:(

    Hope this helps.
     
  7. dbstoo

    dbstoo Active Member

    Joined:
    Oct 7, 2012
    806
    425
    0
    Location:
    Near Silicon Valley
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    You can't please everyone. I do a lot of driving on dynamic CC (1 or 2 thousand miles) every month and find the acceleration when resuming CC is close to what I would do manually. There is nothing dangerous about it.

    On the other hand, When I go from CC to brake to manual acceleration it is not as smooth as I would like. I'm used to it but my wife freaks. The solution is to disengage CC before hitting the brakes and then gas.
     
  8. mysacramento

    mysacramento New Member

    Joined:
    May 28, 2021
    8
    3
    0
    Location:
    sacramento
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    thank you for all your comments and tips.
    I drove several cars in the past and present with cruise control, they don’t accelerate so fast.. try, like i said i also used to own a toyota sienna with dynamic cc and accelerate smoothly
    and like i said again what’s the point of saving gas if when resuming the set speed the engine goes to red area

    all i am saying is that i think the car should resume the set speed smoothly just like other cars i drove, that’s all

    all solutions you provided sound like work-around, not really a solution

    i think toyota should program the dynamic cc little bit better and i don’t know if there is actually a way to let them know
     
  9. dbstoo

    dbstoo Active Member

    Joined:
    Oct 7, 2012
    806
    425
    0
    Location:
    Near Silicon Valley
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    I think that's your problem right there. You have expectations based on previous experience with a different product. That happens all the time when people move from iPhone to Android or Starbucks to Peets coffee. They expect what they are used to from the previous products. Never mind that the behavior of the previous models might not be part of the design. It might just as easily be a side effect of how much power the car has available.

    My 2017 does not usually rev into the red zone just to catch up with the car ahead of me. When it does, I don't worry about it because it takes only a matter of seconds to get back to my 'max speed' or to get close to the car that I'm following. I use the max following distance, so I almost never take it out of DCC while on the freeway at speed.

    If you are frequently needing to take your car out of DCC and resuming it, maybe you are not driving it in the conditions where it's supposed to be used? Like mountains or city streets?
     
  10. FuelMiser

    FuelMiser Senior Member

    Joined:
    Jun 29, 2008
    1,039
    732
    0
    Location:
    Monument, CO
    Vehicle:
    2016 Prius
    Model:
    Touring
    I doubt there's anything wrong with your car. This is purely conjecture since I do not drive a Prime, but could it be you're experiencing too rapid acceleration for your taste simply because of the instant torque of pure EV acceleration vs. HV acceleration? I understand from the Forum that the Prime accelerates much more briskly than a Prius Hybrid when in EV mode.
     
  11. vvillovv

    vvillovv Senior Member

    Joined:
    Mar 19, 2013
    2,464
    886
    1
    Location:
    NY
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    What other ways can we offer? I'm pretty sure Toyota is not going to change the behavior of the cruise control, especially since there are several ways to use it (or more importantly not use it) that should satisfy most drivers. I have my issues with the way dynamic cruise in certain situations too, mostly just behavior of other drivers though, so I'm much more comfortable using regular cruise when there is the possibility of experiencing the behavior I don't like when using dynamic cruise.
    If you've registered at My Toyota there may be a way to report your issue there.
     
Loading...