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Vehicle Stability Control,

Discussion in 'Knowledge Base Articles Discussion' started by fuelsipper, Nov 5, 2005.

  1. fuelsipper

    fuelsipper New Member

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    On step driveways (ours) and steep roads, the wheels spin when the pavement is wet and then the power to the wheels stops for a second. Also, forward momentum stops, making is very difficult to progress up our driveway(when wet) Can the VSC be turned off? and I am assuming it is the VSC that is causing the problem.
    Thanks for putting up with my lack of knowledge,
    Eric
     
  2. popoff

    popoff New Member

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    I've encountered the same problem going up a not too steep gravel driveway. I wound up having to back up the driveway to get to the top.

    Unfortunately, I'm pretty sure the VSC can not be turned off.
     
  3. NuShrike

    NuShrike Active Member

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    Brian of BT Tech in his dyno tests thread found a way to permanently disable TRAC. Unfortunately, it also disables ABS, VSC, and probably EBD (electronic brakeforce distribution).

    [edit]
    As what PriusEnvy says, Traction Control is what you're encountering.
     
  4. priusenvy

    priusenvy Senior Member

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    For the thousandth time:

    That's not VSC, that's TRAC!!!
     
  5. tumbleweed

    tumbleweed Senior Member

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    If it were VSC you would hear the beeper, I don't remember hearing it for traction control. Anyway priusenvy is correct it is traction control in the circumstance you describe, and neither trac or VSC can be turned off in the Prius. Some cars yes, but not this one.
     
  6. craigcush

    craigcush Member

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    Only solution is to get better tires. Tons of threads here covering choices and experiences of drivers with alternate treads.

    Your not the first, this comes up with the weather change, especially snow.
     
  7. Tideland Prius

    Tideland Prius Moderator of the North
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    Ditto.


    The only solution is to get better tyres. Unlike other traction control systems, this one is designed to protect the eletric motor. Overrev it and pay the price of an electric motor or two.
     
  8. fuelsipper

    fuelsipper New Member

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    2005 Prius for sale...kidding. Grippy tires it is.
     
  9. Tideland Prius

    Tideland Prius Moderator of the North
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    :)

    TripleTreds should do you good
     
  10. BT Tech

    BT Tech New Member

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    IMO, Toyota really should have provided a switch to turn off the traction control for the reasons mentioned in this thread.

    The ONLY way I was able to disable the traction control (VSC) was to physically disconnect the rear sensors on the hubs. This way the computer has no idea what the rear wheels are doing in relation to the front wheels and sets an error code which disables the traction/abs control.

    The EBD (electronic brakeforce dist) is not affected.


    Thanks!!

    Brian
    BT Tech
    305-652-3115


     
  11. Tideland Prius

    Tideland Prius Moderator of the North
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    Traction control isn't VSC. VSC is Vehicle Stability Control. It's for yaw management. Traction Control (TRAC in Toyota terms) is for limiting wheel spin. Toyota vehicles can disable TRAC but not VSC. (Oddly enough, Honda allows you to disable VSA but not TCS). On the Prius, you can't really do that as its designed to protect the motor.


    However, I have a question for Classic owners. The Classic doesn't have TRAC, so how exactly does it prevent overrevving of the motors?
     
  12. Tideland Prius

    Tideland Prius Moderator of the North
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    Traction control isn't VSC. VSC is Vehicle Stability Control. It's for yaw management. Traction Control (TRAC in Toyota terms) is for limiting wheel spin. Toyota vehicles can disable TRAC but not VSC. (Oddly enough, Honda allows you to disable VSA but not TCS). On the Prius, you can't really do that as its designed to protect the motor.


    However, I have a question for Classic owners. The Classic doesn't have TRAC, so how exactly does it prevent overrevving of the motors?
     
  13. tumbleweed

    tumbleweed Senior Member

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    Does anyone know for sure if the traction control on the Prius is there to protect the motors? I think the computer could, and most likely does, do that by limiting the frequency of the power from the inverter being directed to the motors. Maybe they were just a little over conservative when they designed the traction control? It would be very useable if it didn't try to limit the front wheel speed based on rear wheel speed, or maybe allow the front wheels to go at least a little faster than the back ones. It would seem that all it should do is to keep one front wheel from turning a lot faster than the other. I am not trying to out guess the design staff but I sure am curious why they did what they did.
     
  14. skijapan

    skijapan Junior Member

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    I owned a '99 Prius for about three years and drove it everyday on the snow-covered roads of Hokkaido. I always felt very safe in that car. I can recall a few times when, in driveways after a big snow, my car would be almost stuck. After the tires would spin a little, it seemed like the power would just cut out. A little gas- nothing. Full gas- nothing. When this would happen, I would put the car into reverse and sort of rock the car out of position by repeatedly pushing down and letting up on the gas, but not all the way. This always seemed to work. It actually worked for going forward too, but it had to be done a little bit in reverse first.

    Now, I'm interested to see how my '05 will perform this winter.
     
  15. Tideland Prius

    Tideland Prius Moderator of the North
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    Hmm, what you described was exactly what I experienced with my '05. I was parked at the side and knew I was stuck the moment I pulled in. Yeah, once the wheel spun and TRAC kicked in, no amount of prodding will get power to the wheels. I had to reverse and rock the car out of the curbside.

    In that case, what's TRAC for since your '99 performed similarly to ours?
     
  16. fuelsipper

    fuelsipper New Member

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    Just called Toyota dealer here in Medford,Or. He said"negative" when I asked him about disconecting the TRAC. He said buy a Highlander.....
    oy.
     
  17. DanMan32

    DanMan32 Senior Member

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    You can disable VSC, basically that amounts to jumping 2 pins on the DLC. However as stated, VSC is NOT trac. Trac is your problem. Yes, it is documented in Toyota's technical site that trac is used to prevent damage to the PSD.

    Now as for saying the car is dead, that is hogwash. The tire has to turn in order to detect lack of traction. Most of us can be overly agressive with the accelerator, especially when we are not aware that we are on a slippery surface. Once the car stops the wheels, it will retry turning the wheels again. If you have the accelerator at the same spot, you will get the same results: stopped wheels. If you instead gently accelerate, you might be able to move, if movement is at all possible.
    When you know you are walking on a slippery surface, do you run through it, or take careful steps, almost tiptoeing? So why do we expect to run our cars through slippery surfaces and get suprised when our cars finally tell us NO!

    You can put the car in maintenance mode, which turns off TRAC, but also has the car ICE run at set RPM steps based on accelerator position.
     
  18. fuelsipper

    fuelsipper New Member

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    I understand there is nothing I can do and can live with it..it's my driveway that I can't live with. Just too steep when it's wet.
    Simple solution: we park the Prius at the top of the driveway when it is wet. No matter how slow we go, and yes, tire pressure is lower than I like, no go.


    Eric
     
  19. smasho

    smasho New Member

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    The classic did have a rudimentary form a TRAC. It wasn't really for driving it was just to protect the electric motors. There was some sequence that you could enter on the MFD that overrode it so it could run on a dyno.

    Funny on the classic I hardly ever spun a tire. Now with the '05, which isn't that much more powerful, and the onset of the rainy season I keep triggering the TRAC.

    It's amazing, the POS OEM Goodyears may be worse tires than the POS OEM Bridgestones on the classic :angry:. The Cubs will win the pennant before I go out and buy either of those disreputable brands.
     
  20. Tideland Prius

    Tideland Prius Moderator of the North
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    Michelin Energy MXV4 Plus. Expensive (at least in Canada) but pretty good. HydroEdge is a cheaper alternative