1. Attachments are working again! Check out this thread for more details and to report any other bugs.

04 Prius always trigger VSC, even for mild stop

Discussion in 'Gen 2 Prius Technical Discussion' started by AllenZ, Oct 20, 2011.

  1. AllenZ

    AllenZ Active Member

    Joined:
    Jul 9, 2010
    640
    63
    0
    Location:
    Chicago
    Vehicle:
    2010 Prius
    Model:
    Four
    today I found when approach a stop sign, VSC always engaged except when I extremely careful.
    It appears nothing is wrong. Temp at 50, very little water on ground. When I just about to completely stop, VSC engages 3 times, and I feel like car suddenly accelerated, then stops.
    Anyone has similar experience?
    Thx
     
    #1 AllenZ, Oct 20, 2011
  2. firepa63

    firepa63 Former Prius Owner

    Joined:
    Jul 23, 2005
    1,761
    208
    0
    Vehicle:
    Other Hybrid
    Model:
    N/A
    How is your tire tread? Worn tires can cause this.
     
    #2 firepa63, Oct 20, 2011
  3. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,081
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Buy new tires with better traction ratings. The 2004-2005 models have a very aggressive traction control system. The only way to reduce the VSC or traction control system engagement is to use better tires. I don't have any issues at all unless I hit ice. I used to experience the traction control power cut frequently when I had to original OEM Integrity tires on the car.
     
    #3 F8L, Oct 20, 2011
  4. seilerts

    seilerts Battery Curmudgeon

    Joined:
    Mar 7, 2010
    3,326
    1,512
    38
    Location:
    Santa Fe, NM
    Vehicle:
    2005 Prius
    How many miles? Ever have a brake job?
     
    #4 seilerts, Oct 20, 2011
  5. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,074
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    It's not VSC. VSC works to keep your Prius going straight and under control, as in losing control around a corner. Generally it's hard to notice VSC, unless you exceed its ability to correct the problem. Perhaps you are thinking of ABS?

    Tom
     
    #5 qbee42, Oct 20, 2011
  6. wjh308

    wjh308 Junior Member

    Joined:
    Sep 25, 2011
    22
    2
    0
    Location:
    San Francisco
    Vehicle:
    2007 Prius
    Model:
    N/A
    Can't say for the Prius, but we took my friends Subaru outback offroad and drove it like a rally car(Very BAD idea).

    Short of the story, having defective or bent backwards ABS sensors on the subaru would trigger the ABS engaging every time the brake pedal was pressed.
    Check your ABS sensors.
     
    #6 wjh308, Oct 23, 2011
  7. jdenenberg

    jdenenberg EE Professor

    Joined:
    Nov 21, 2005
    3,852
    1,847
    1
    Location:
    Trumbull, CT
    Vehicle:
    2020 Prius
    Model:
    LE AWD-e
    The last time someone posted symptoms like this it was due to mismatched tires.

    Are all of your tires the same size? Are some of the worn and the others relatively new?

    Any difference in tire circumference can cause the ABS to have a hair trigger.

    JeffD
     
    #7 jdenenberg, Oct 23, 2011
  8. AllenZ

    AllenZ Active Member

    Joined:
    Jul 9, 2010
    640
    63
    0
    Location:
    Chicago
    Vehicle:
    2010 Prius
    Model:
    Four
    Thank everyone! You guys hit the nails on all accounts. But what still puzzles me is that it never happened before!

    Yes I have mismatched tires on front, a Goodyear viva 2 with 4/32 and a Cooper with 8/32 roughly. The rear tires are viva with 5/32 left.

    I will replace 3 viva and put the Cooper to rear.

    Just bought 3 almost new tires at price of one (10-11/32), two of them are also viva 2, and the other is Goodyear Integrity. The seller is a Toyota technician. He said those tires come from trade in cars. In order to certify those trade ins, the dealer replaced those mismatched almost new tires before put the car on sale. He said that I will not feel any difference if I mismatch the Cooper and Integrity in rear.
     
    #8 AllenZ, Oct 25, 2011
  9. seilerts

    seilerts Battery Curmudgeon

    Joined:
    Mar 7, 2010
    3,326
    1,512
    38
    Location:
    Santa Fe, NM
    Vehicle:
    2005 Prius
    Since the front wheels do almost all of the stopping work, having a matched pair up front will definitely confirm or rule out tires as the cause. You have mentioned treadwear, but what about the size of the Cooper vs. the Goodyear?
     
    #9 seilerts, Oct 25, 2011
  10. wjh308

    wjh308 Junior Member

    Joined:
    Sep 25, 2011
    22
    2
    0
    Location:
    San Francisco
    Vehicle:
    2007 Prius
    Model:
    N/A
    If mismatched tires are the cause, then I would expect the included donut spare tire to cause the same problem. Somehow though, I don't think Toyota would let that one slip by..
     
    #10 wjh308, Oct 27, 2011
  11. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,074
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    It will. It's not a good idea to do much driving with the spare on the front.

    Tom
     
    #11 qbee42, Oct 27, 2011
  12. AllenZ

    AllenZ Active Member

    Joined:
    Jul 9, 2010
    640
    63
    0
    Location:
    Chicago
    Vehicle:
    2010 Prius
    Model:
    Four
    Size are all same, 185/65/15
    Theoretically, thread wear affects size, but I think it is negligible.
     
    #12 AllenZ, Oct 28, 2011
  13. AllenZ

    AllenZ Active Member

    Joined:
    Jul 9, 2010
    640
    63
    0
    Location:
    Chicago
    Vehicle:
    2010 Prius
    Model:
    Four
    That's a good argument I think.
    Maybe Toyota engineers are smart enough to build their VSC software to handle the spare tire case, since it is a known significantly smaller size.
     
    #13 AllenZ, Oct 28, 2011
  14. AllenZ

    AllenZ Active Member

    Joined:
    Jul 9, 2010
    640
    63
    0
    Location:
    Chicago
    Vehicle:
    2010 Prius
    Model:
    Four
    I read long time ago, that the first 10 minutes of raining period is the most slippery period, because the oil on the road is not washed away.

    In my case, it rained a very little but stopped a while ago. There is no visible water reflection on road, but I can definitely tell it is still wet.
     
    #14 AllenZ, Oct 28, 2011
(You must log in or sign up to post here.)