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Releasing Cruise Control with Brake

Discussion in 'Gen 3 Prius Main Forum' started by jburns, Oct 1, 2009.

  1. tochatihu

    tochatihu Senior Member

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    Suggest that 2010 Prius owners needing to do this hard brake press, confirm that the brake lights indeed show with a light brake pedal press. If not your switch needs to be adjusted. I would be entirely surprised if such an adjustment were not done for free.
     
  2. garygid

    garygid Senior Member - Blizzard Pearl

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    On my P-III, I have to depress the brake pedal about 0.5 inch to turn on the brake lights - tested in "aux" mode. Perhaps that is considered "normal"?
     
  3. jburns

    jburns Senior Senior Member

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    That measurement really has no significance since there can be a varied amount of play in any pedal. What has not been normal in any car I have ever owned is the inability to release the cruise control with the brake pedal without significant braking action occurring.

    A sleeping passengers head should not be rolling around every time you release the cruise control. It is abnormal behavior and it doesn't really matter if you can learn a work around. I can roll down the window and stick my arm out to legally signal a turn but I still want my turn signals to work.
     
  4. garygid

    garygid Senior Member - Blizzard Pearl

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    So, what is the spec. for normal adjustment of this brake switch on the Gen3?
     
  5. Grateful11

    Grateful11 Member

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    I've had like 17 vehicles since '84 and the Prius is by far needs the most brake pedal pressure to turn off the cruise. My son's Scion xD also needs too much pedal pressure to release the cruise.
     
  6. garygid

    garygid Senior Member - Blizzard Pearl

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    The OM says the CC is, "... canceled when the brakes are applied."

    So, does one just need to press the brake pedal enough:
    1. for the brake lights to come on (most likely)
    2. for an increased amount of regen to occur (probably not)
    3. for the mechanical brakes to be applied (very unlikely)

    However, it is difficult to tell when the brake lights go on when "cruising" ... unless one tapes a small piece of paper loosly over a small section of the 3rd (upper, center) brake light so that one could see (through the rear-view mirror) the brake light glow on the paper?

    Is there a separate brake-light switch on the brake pedal (like most cars), or does the computer just read the pedal position and the firmware decides when to turn on the brake lights?
     
  7. archermoo

    archermoo New Member

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    Yeah, well, that's what I get for replying while I'm at work. When I first started my reply yours wasn't there yet. It just took me a while to finish my reply. Work has been busy. :)
     
  8. tochatihu

    tochatihu Senior Member

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    Before 2010 Prius it was a single throw double pole switch (your first option). Some of those switches caused problems in 2004 and Toyota issued a fix. I don't know this detail of the new model.
     
  9. hobbit

    hobbit Senior Member

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    The absolute *last* way I'd disengage CC is with the brakes,
    unless I actually had to stop in a hurry. If I use it at all,
    which is rare, the challenge is then to disengage it *without*
    any lurch at all. In cars with old mechanical cruise-controls
    one could push the go-pedal far enough to feel it come up against
    the throttle mechanism where the CC was holding it, and then
    disengage CC without having the throttle move at all and just
    smoothly take over. That's really *hard* in a Prius as there's
    no mechanical detent in a fly-by-wire pedal; you have to press
    a bit and guess about where the current demand is and try to
    match it. I cheat, looking for a tiny upward blip in the current
    meter that indicates the beginning of increased acceleration,
    and then back off epsilon and pull the stalk. Bing, smooth
    transition with no speed change or the car "falling on its face"
    into regen drag.
    .
    _H*
     
  10. Holmesman

    Holmesman Junior Member

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    I'm glad I saw this post. The first time I used cruise control on my new Prius IV I was surprised how hard I had to press on the brake to disengage it. Now I use the lever on the steering rod to cancel it.

    My brother drove the car for the first time yesterday and he had it in cruise and when he used the brakes to disengage it, everyone in the car lurched forward. Toyota needs to address this.
     
  11. MaggieMay

    MaggieMay Active Member

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    +1 Holmesman - I just returned from an all-interstate trip of over 1000 miles and was puzzled why the CC didn't respond to braking as in previous cars. If I'd seen this thread first - it would have made the drive a little easier!
     
  12. Grateful11

    Grateful11 Member

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    I agree mine is applying the brakes before it turns off, I can feel it.

    Is it switch at the back of the pedal or is it shut off with pressure on the Master Cylinder?
     
  13. IraS

    IraS Member

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    I noticed the same thing and I was wondering if I was imagining it.

    I don't use the brake to disengage the cruise control. I use the brake to slow down (like when someone cuts in front of me and the dynamic radar cruise control can't handle the sudden appearance of a new, slowly moving vehicle), and expected the cruise control to disengage, as it did in all previous vehicles, including the 2004 Prius. I was surprised that the cruise control stayed engaged after pressing the brake pedal.

    Now I know this is "normal" behavior.
     
  14. The Electric Me

    The Electric Me Go Speed Go!

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    The problem with this is that if someone isn't aware of the problem and is tapping on the brakes expecting the CC to cut out and it doesn't, a "normal" situation could become an abnormal situation very quickly.

    Seems like something Toyota needs to address.
     
  15. David Beale

    David Beale Senior Member

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    The CC uses one of the two switches on the brake arm (the brake light switch). In a Prius it's usually adjusted so you actually have to be into hydraulic braking before it actuates. So because regen. braking is so effective you perceive the brakes are on -before- the brake lights are actuated. I -strongly- recommend every owner back close to a wall or mirror type surface at night and actually -watch- how the brake lights work re pedal pressure. With the car running in "D" (apply the parking brake if that worries you).

    Using the brake to shut off CC is "messy". I never liked doing that (probably because a previous Toyota would actually drop the set speed when you pressed on the brake pedal - it is actually an "emergency feature"). That 4Runner wouldn't drop the set speed if you first canceled cruise then applied the brake.

    Just pull up on the CC stick to cancel and you'll be fine. In fact I "drive" using the CC stick. To increase speed gradually just bump the stick up for each MPH more (I have to use math as I'm using km/hr ;) ). You have to hold it down to slow down, and it's probably not a good idea as the Prius doesn't slow very fast (darn efficient car). Pull toward you to cancel. Press down to resume. Or press up to set a new speed once canceled.
     
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  16. Jim05

    Jim05 Occasional Quasi-Hypermiler

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    I'm seeing the same problem with CC myself, but have also noticed that brake lights don't come on until I've pressed the brake about 1-2 inches. It wouldn't be so bad if this was simply free pedal travel, but there is significant enough slowdown that I've nearly been rear-ended on several occasions. I first chalked it up to morning drivers who were still drinking coffee or putting on makeup, but started paying more attention to the reflection in my rearview and noticed the brake light wasn't coming on until I was slowing down pretty significantly. Agree with previous post that it's likely a switch adjustment, so will have to take the car in to see what they can do about it. Hopefully, this isn't chalked up as a 'design feature'.
     
  17. dmvp

    dmvp Member

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    If you notice on the Cruise Control stick it says, "release" and has an arrow. It's much easier to pull the stick towards you to stop the cruise, than it is to hit the brakes. With regen brakes it makes much more sense to do it that way.
     
  18. tumbleweed

    tumbleweed Senior Member

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    Yes there is a big difference between how far you need to push the brake to disengage the CC on the Gen3. On my Gen2 just a normal tap on the brake pedal, such as on most other cars, would disengage; on the Gen3, as noted by others, you have to push until the brakes (regen or friction) start slowing you before the CC disengages.

    I took my car to the dealer to have the switch adjusted, they wouldn't adjust it because they said the brake light and the cruise control use the same switch and if the cruise control is adjusted correctly the brake lights might stay on. I believe that they do use the same switch because he looked it up, the rest of what he told me is just pure BS. I didn't argue the point because that never gets you anywhere with people who are convinced they are always right and the customer is always wrong.

    However I did have them show me where the switch is but I haven't tried to adjust it yet because it's fairly hard to get at.

    I usually disengage the CC with the steering wheel stock but there are times when I would like to do it by taping the brake pedal, and not have the brakes applied. There is nothing wrong with disengaging the cruise control with a tap on the brake pedal if the switch is adjusted correctly, when I see the brake light flash on cars ahead of me and they start slowing I know exactly what they did and I may need to start slowing as well.

    I think Toyota needs to start adjusting these things correctly at the factory, like they did with the Gen2, and instruct the service departments how to do so. It might even be a good idea if they would spend a few extra pennies and put in separate switches for the two functions.
     
  19. Bobsprius

    Bobsprius BobPrius

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    I agree with JIM05, I have been watching my Brake Lights and they appear to come on later than I would like, meaning unless extensive pressure is applied to the pedal the lights don't come on even though you are slowing down. I have noticed this and have corrected by hitting the brakes harder but will also be checking with my dealer on the first service visit, to see if they can adjust the Switch that will allow the brake lights to turn on. I can easily see this at night on the reflecting vehicle from behind. Light pedal pressure will not turn them on, only more agressive pedal pressure does this.
     
  20. adamssta43

    adamssta43 New Member

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    yes this is true. I normally just push the button to turn off the cruse. seems easier that way. it definitely takes more than a normal tap.