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VSC, (!), ABS, Brake Light - ONLY above 60mph

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by DaveD9664, Sep 9, 2017.

  1. DaveD9664

    DaveD9664 New Member

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    Hi guys n gals.

    2007 prius. 118k miles.

    Got the VSC, (!), ABS, Brake Light combo going on. But here's the catch. It only happens on the freeway above 60mph. After I get off, they go away.

    uhhh, what?

    Replaced inverter coolant pump. Works now. Awesome.

    Gonna check the HV battery fan and vent now.

    Any body have a remedy for this?

    Thanks
    Dave
     
  2. JC91006

    JC91006 Senior Member

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    You probably have a bad sensor. You need to read the codes to figure out which one to replace.

    Just curious, do you have all 4 tires that are the same size?
     
  3. DaveD9664

    DaveD9664 New Member

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    Will the code still be readable even though the lights turn off after I go below 60?

    Any recommendations for a scanner? I have a mac
     
  4. fuzzy1

    fuzzy1 Senior Member

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    That is also my first thought.
     
  5. ChapmanF

    ChapmanF Senior Member

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    Mine too. The difference in rpm, small at low speeds, might be large enough over 60 to trigger a speed sensor code. Reading the codes will help.

    Reading the freeze frame saved at the moment the code was set should reveal information including what the wheel speeds were at that moment.

    -Chap
     
  6. DaveD9664

    DaveD9664 New Member

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    hey thank for your thoughts everyone! I checked the tires. they all seem to be the same model. I seen a difference in a rating called MBH? two said 12 one at 04 and one at 05? The rating was right next to a rating that read "rim"
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Did you check the tire air pressure?
     
  8. DaveD9664

    DaveD9664 New Member

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    Yes I have the tire pressure at about 45. only 1 over the max. Could that be it?
     
  9. DaveD9664

    DaveD9664 New Member

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    If i remember correctly, this was happening on the drive home when i bought it, which was before i put that much air into it.
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    That would not be the cause of the problem if all 4 tires have that air pressure.
     
  11. fuzzy1

    fuzzy1 Senior Member

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    No. Matching pressures won't cause this. Significantly mismatched pressures should not be cause it either, that should cause TPMS alerts first.
    In addition to the same model, are they also the same tire size?
     
  12. DaveD9664

    DaveD9664 New Member

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    all of them say the same exact thing, except that weird mbh rating. same exact models. shall i take a measuring tape to em?

    Also, can someone link me to a mini scanner that comes with software compatible with a mac that is under 50 bucks? Ill get to the bottom of this!
     
  13. DaveD9664

    DaveD9664 New Member

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    previous owner said he changed the rotors... or the brakes. or something to do with that, he didnt speak great english and the vehicle had so low miles for the price he was asking so i just went with it. could this be a cause?
     
  14. ih8spm

    ih8spm Junior Member

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    I'm in a similar situation and without the ability to read the codes. Following this thread.

    SM-G935P ?
     
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

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    You will need BootCamp and Windows 7, 32 bit OS. Then get Mini VCI on amazon.com which is bootleg Toyota Techstream.
     
  16. DaveD9664

    DaveD9664 New Member

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    Pat, Can you point me to the right one?

    When I look on amazon, some of the reviews are saying these bootleg disks have viruses on them!

    Will a regular OBD2 grab this code?
     
  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    #17 Patrick Wong, Sep 10, 2017
    Last edited: Sep 10, 2017
  18. ChapmanF

    ChapmanF Senior Member

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    The deal in that link is for a subscription to TIS Pro (the "Standard" level doesn't include the Techstream software access) for one year ($1095) and a MongoosePro J2534 dongle ($495) to connect your computer's USB port to the car, all discounted to $1345.

    However, the Pro-level subscription also comes in a two-day, $55 flavor (subscription options), and the $495 MongoosePro isn't the only J2534 dongle the software can work with; it's just the one they test with, so if you use a different one and it's flaky you're on your own.

    -Chap
     
  19. suzygoblue

    suzygoblue Junior Member

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    My 08 has similiar problem. The VSC light comes on at speeds over 65. Dealer did not find any code to indicate the problem but did a reset. Light still comes on. As I recall this started after I got two new front tires. Is there any relationship to this?
     
  20. ChapmanF

    ChapmanF Senior Member

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    That's quite possible. Tire diameter decreases with age as the rubber wears off, so the older, smaller ones spin more revolutions to cover the same distance. The ABS/VSC system monitors all four wheel speeds to detect any conditions (like lost traction or an incipient skid) where the wheels aren't turning the same speed.

    The difference in speeds between your old worn-down tires and new full-diameter ones will be strictly proportional to how fast you're moving down the road. The difference at 60 mph is four times the difference at 15 mph. At some point it may be large enough that the skid computer says "Wth?".

    You can retrieve the trouble codes from the skid computer using a paper clip, which may confirm the theory here, or reveal that something else is going on. You can also get a "freeze frame" of just what was going on when the lights came on: all wheel speeds, straight or turning, g forces on the car, etc., but not with a paper clip; that requires Techstream.

    -Chap