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Does ECU Upgrade Fix 04/05 Traction Control?

Discussion in 'Gen 2 Prius Main Forum' started by nyprius, Dec 16, 2007.

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  1. Tideland Prius

    Tideland Prius Moderator of the North
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    It's not that the car works better or not.


    I know what I saw (felt?) when that TRAC killed the power. I was there with the windows down and my friends were watching me pull out. I decided to test the TRAC and it killed the power and no amount of prodding would make the car go forward.


    Fast forward to the first snowfall after my ECU was replaced. I was backing into the garage. That was the first time ever that I heard the wheel spin, then catch (i.e. braked) then spin. I was caught by surprised esp. since back then we were all talking about how the TRAC was dangerous, that it cut power etc etc.

    Also then was a bunch of new 2006 owners saying that theirs allowed wheel spin and we thought they didn't know what they were talking about cause their cars was new. I believe there was a debate thread somewhere too (there's only so much of PriusChat I can remember!).

    Using the pieces of information I gathered from all the threads, that's how I came to that conclusion (and probably stopped a bloody battle btwn the pre and post 06 owners). I'm kidding about the stuff in the brackets.


    Mine's an early 2005. It was built in Sept 2004 so I'm one of the first to get a 2005 model. So even if I couldn't find proof, why would mine allow wheelspin and the other early 2005s (like yours) can't? (Someone with a later 2005.. i think was bought in june or july said that theirs allowed wheel spin)
     
    #21 Tideland Prius, Dec 17, 2007
  2. nyprius

    nyprius Member

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    Thanks Tideland Prius. This is good information. But unfortunately, it's not conclusive. I can't take it to my dealer and get them to fix my traction control. I wish there was some way get a service bulletin or dealer receipt showing specifically that traction control was upgraded. This is the type of information we'd need to get a dealer to do the work. In the past, dealers have told me it was not possible to convert the traction control from full stop to limited slip.

    Would the dealer that replaced your ECU give you some written verification that your traction control was improved as a result of the ECU replacement?
     
    #22 nyprius, Dec 17, 2007
  3. Tideland Prius

    Tideland Prius Moderator of the North
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    Yeah I know what you're trying to get. And the dealer won't change the ECU for no reason unless you have written proof, right? I can't help you there :(


    I doubt it. The fried ECU was part of a string of problems (which also include battery degreaser in the interior, poorly fixed A-pillar and MFD plastic surround, scratches on my dashboard.... ya they made a mess of my car >.<).

    Plus when I asked them to change my interior fadeout time from 15sec (default) to 30 secs, they were like "you can do that?!"
    :rolleyes:
     
    #23 Tideland Prius, Dec 17, 2007
  4. galaxee

    galaxee mostly benevolent

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    no ecu update that DH knows of that would "fix" the tc issue. he thinks that's all in the skid control ecu. but we don't have tis anymore to verify and his head's aching pretty bad.
     
    #24 galaxee, Dec 17, 2007
  5. Tideland Prius

    Tideland Prius Moderator of the North
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    wha??

    so how many ECUs did I have replaced then?!? How many did my "Prius Tech" fry?
     
    #25 Tideland Prius, Dec 17, 2007
  6. nyprius

    nyprius Member

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    Galaxee, apparently you asked DH (whoever that is) about fixing traction control. Did he say the skid control ECU was changed in 06 to fix traction control? Can you please provide more information about this or tell me where I can get it so that I can get the dealer to fix the problem on my car. Thanks!
     
    #26 nyprius, Dec 18, 2007
  7. galaxee

    galaxee mostly benevolent

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    no evidence in new car features that the skid control ecu was changed in 06.
     
    #27 galaxee, Dec 18, 2007
  8. nyprius

    nyprius Member

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    Thanks Galaxee. It sounds like you have access to some information. Can you get more information from DH or elsewhere about improvements to the traction control through skid control ECU upgrade/replacement or other means?
     
    #28 nyprius, Dec 18, 2007
  9. Tideland Prius

    Tideland Prius Moderator of the North
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    DH is dear husband. He's a well-respected Prius technician here on PC (through Galaxee). He's taken apart the fuel tank and shown us the bladder, he's shown us a HiHy inverter and goodness knows what else we wouldn't dare do on our own.
     
    #29 Tideland Prius, Dec 18, 2007
  10. galaxee

    galaxee mostly benevolent

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    unfortuantely, nyprius, it looks like there aren't any.
    DH said last night: no, the recall flash that Tideland had shouldn't affect the trac, that should be regulated through the skid control ecu.
    we actually got ourselves a connection to tis again, so i checked out the improvements listed for the 06 MY and found nothing related to the skid control ecu. i'll check again tonight if you'd like.

    DH is a former prius tech who's out of the car repair biz.
     
    #30 galaxee, Dec 18, 2007
  11. nyprius

    nyprius Member

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    Thanks Galaxee! I'd appreciate any information you or DH could provide on this (and I assume others with 04/05 Prius's would as well).

    Concern about lawsuits may be causing Toyota to remain silent on this issue. I know they have gotten many complaints about the flawed Prius traction control from consumers and consumer advocate organizations.

    In addition to sometimes causing the car to slide backwards uncontrollably on slippery hills, the flawed traction control can cause the Prius to stop dead with traffic bearing down on you as you pull onto a busy road or highway (as pointed out above). This is clearly a major problem, probably more worthy of a recall than the steering upgrade done a couple of years age. Yet it hasn't happened. I don't understand why.

    It seems that PC members are a large and dialed in group. We should be able to figure something out on this.
     
    #31 nyprius, Dec 18, 2007
  12. galaxee

    galaxee mostly benevolent

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    oh, i know about it. i've got an 05 too, and on those pos integrities i found myself in a couple sticky situations. but you have to remember that spinning the tires can cause major issues with the HSD system. i don't think they've released parts that will allow for any kind of wheel spinning, and of course down here there's no chance to drive in the snow like you guys up north have so DH isn't aware of any differences in snow between the 05 and 06.

    there was no published change in the skid control ecu anyway.
     
    #32 galaxee, Dec 18, 2007
  13. daniel

    daniel Cat Lovers Against the Bomb

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    This has never happened to me in my early 2004. If the road surface is slippery (snow, ice, or even sand) it will accelerate much more slowly than I expected, and that has given me a couple of scares. But it's never stopped dead. (Again, I'm talking here about flat ground.)
     
    #33 daniel, Dec 18, 2007
  14. nyprius

    nyprius Member

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    Thanks Galaxee, There's plenty of anecdotal evidence on this and other threads to indicate that there probably is a difference between the 04/05 and 06+ traction controls. Hopefully we'll be able to dig up some documentation that allows 04/05 Prius owners to get safe traction control.

    Re protecting the HSD, that's an engineering issue that smart Toyota engineers can figure out (or perhaps already have). It doesn't seem like a big problem because we're not talking about freely spinning the wheels at high speed. Limited slip traction control would only allow slower spinning (I think).
     
    #34 nyprius, Dec 18, 2007
  15. Tideland Prius

    Tideland Prius Moderator of the North
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    Note that I never got a flash cause my ECU died remember? I got a replacement one.

    But then something changed because the 04s and some 05s react differently than the 06+ models. So that means the VSC ECU was changed?

    But yet there has been no documented changes in the VSC ECU software?

    hmm.... the computer can't just magically decide whether to spin or to completely cut the power.
     
    #35 Tideland Prius, Dec 18, 2007
  16. galaxee

    galaxee mostly benevolent

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    ok, DH is in far better shape tonight. he was able to confirm that the trac is run through the hv ecu (oops). toyota's limited slip trac is not software-driven. it is implemented by different hardware (differential). so there's no way it could have been converted to limited slip through a software upgrade.

    the ecu reflash updated older software to the current version- so if you have an 05 that was made late enough to not be affected by the recall, you've already got the same software they were upgraded to.
     
    #36 galaxee, Dec 18, 2007
  17. F8L

    F8L Protecting Habitat & AG Lands

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    I want my tires to spin. :(

    The car just drops power for a second then slowly picks back up. I have a late 2005 (October).
     
    #37 F8L, Dec 18, 2007
  18. nyprius

    nyprius Member

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    Thanks Galaxee and Tideland Prius, I picked up my 05 Prius in late 04. So I have an early one. But I had a software upgrade done by the dealer a couple of years ago. I assume that's the one you're talking about.

    Also, thanks to DH for info on the traction control. I'm not a mechanic, so I'm not completely clear on a mechanical system could sense slippage, cut power, then parcel it back out in a strobe like manner, without some kind of electronic control. That of course is not to say it's not possible!

    I wish there was some way to get a definitive answer to questions like, is there a difference between 04/05 and 06+ traction control? Can the 04/05 TC be fixed so it doesn't come to a full stop?

    It would be nice if Toyota provided a definitive answer on these issues.
     
    #38 nyprius, Dec 18, 2007
  19. Tideland Prius

    Tideland Prius Moderator of the North
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    ok.. but those two were the ones that got flashed - engine and HV (I know cause he forgot to flash the HV cause he was so concentrated on getting my replacement engine ECU :rolleyes:).


    Just wondering how Toyota did it then.

    F8L, it's not quite spinning. I mean, it slips then grips when the ABS/TRAC applies the brakes then slip then grip and so on.

    However, my brother did manage to get them to spin (and hopefully he didn't destroy anything cause there was a burning smell afterwards lol). I won't post what I did here. Don't want to leave any incriminating evidence :p.

    But it's definitely different.

    The only way is if someone with an 04 can test in the deep loose snow that theirs also slip and grip rather than just have a power kill.


    nyprius, yeah it is frustrating especially since you know what you want and they say there's no difference and back and forth.
     
    #39 Tideland Prius, Dec 19, 2007
  20. jayman

    jayman Senior Member

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    In that case, mine completely kills all power. It feels like the car is straining to move, but the wheels don't turn. All the time the Trac light on the dash is blinking.

    With the studded Goodyear Nordic tires, my Prius is now quite good as a winter driver on *average* winter roads. Ice is no problem at all, I can easily blow the doors off 4WD's on "all season" tires when the light turns green.

    Once the car bogs down, forget about it. I can't even rock the bloody thing
     
    #40 jayman, Dec 19, 2007
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