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TC, Brake and ABS all on (then goes off / back) + abnormal breaking

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by PanzerFreak, Jan 12, 2017.

  1. PanzerFreak

    PanzerFreak Junior Member

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    I was driving home from work today when the traction control, brake light and ABS lights all came on my 2010 Prius. I noticed that when the lights were on my ability to break seemed reduced, suddenly it became more difficult to break. After driving a bit more the lights went off (breaking capacity then restored) but then came back on about 10 minutes later.

    I parked my car, turned it off, turned it back on but the lights were still on. Once again I drove a bit with the lights on, noticed the reduced breaking capacity and then the lights went off (breaking capacity was then restored).

    Could this be a 12v battery issue or something else? My car has 120k on it and still has the original 12v battery.

    Thank you
     
    #1 PanzerFreak, Jan 12, 2017
  2. ChapmanF

    ChapmanF Senior Member

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    There are a lot of possible reasons. When the computer running the brakes decides to turn on those warning lights on the dash, that's because it has detected certain specific problems, and the way to get put on the right track to the problem is to ask the brake computer to give the code(s) for the trouble it detected.

    A Prius-aware code scanner (something like a Mini VCI with Techstream is ideal) is the usual way to read out the codes, but if you don't have one and are in a hurry, the Gen 3 brake computer still has an old feature where you can tell it to blink the codes out to you on the dash warning light. You just count blinks. All you need to do that is a short piece of wire (and to find one of the older PriusChat posts giving the procedure).

    -Chap
     
    #2 ChapmanF, Jan 13, 2017
  3. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    I've had similar, plus Check hybrid system warning. Brakes seem to be operating on some default setting: they work, but not as responsive?

    Dealership has checked and cleared codes about 3 times. Nothing conclusive. Latest time over a year back now, and the mechanic testing noticed intermittent blips when jiggling his connection to obd.

    Accordingly suspected it might be constantly connected scangauge. I disconnected since, with no further occurrences.
     
    #3 Mendel Leisk, Jan 13, 2017
  4. PanzerFreak

    PanzerFreak Junior Member

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    Thanks guys for the tips and information. I started my car this morning and the lights turned off, then came back on 15 minutes later (breaking capacity reduced again) and then turned off again (breaking capacity) restored. Weird.

    I called my local Toyota dealer and got a quote for the 12v battery replacement. $230. The parts guy I talked to was thinking this behavior could possibly be related to the hybrid battery itself going bad? I sure hope that wouldn't go bad already, not at 120k miles. Replacement quote for the hybrid battery was $3k...
     
    #4 PanzerFreak, Jan 13, 2017
  5. bisco

    bisco cookie crumbler

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    i doubt it's either one. i would test the 12v, but if it's original, won't hurt to replace it. how many miles on her?
     
    #5 bisco, Jan 13, 2017
  6. PanzerFreak

    PanzerFreak Junior Member

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    I'm now at 120,000 miles.
     
    #6 PanzerFreak, Jan 13, 2017
  7. bisco

    bisco cookie crumbler

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    could be something in the brake system. you really need the trouble codes. are you in a carb state?
     
    #7 bisco, Jan 13, 2017
  8. PanzerFreak

    PanzerFreak Junior Member

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    Could very well be. When the TC, brake and ABS lights were on I had to break fairly hard at one point and noticed a slight grinding noise coming from I think the back drivers side tire. Looks like Michigan is not a carb state.
     
    #8 PanzerFreak, Jan 13, 2017
  9. PanzerFreak

    PanzerFreak Junior Member

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    Well, I think I may be bringing my car to the dealer to have this checked out. The problem keeps occurring on and off. I'm going to see if I can catch the codes with my OBD2 scanner. I also noticed another grinding noise when the 3 sets of lights were on. The sound seemed to be coming from either one of the wheel wells or directly under the car.
     
    #9 PanzerFreak, Jan 15, 2017
  10. PanzerFreak

    PanzerFreak Junior Member

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    Hi guys,

    Over the past 2 years I've had the issue on and off with the TC, brake and ABS lights coming on and breaking capacity being reduced by around 50%. I've noticed that the issue would only happen in winter months during freezing weather. Last October I finally replaced the 12v battery and to my surprised the issue didn't happen once all winter. It's May now and the last 3 times I've driven the my car the same 3 lights have been on at startup and my breaking capacity is reduced by 50%. Car is a 2010 Prius with 155k miles on. Brake fluid level looks good.

    Has anyone else had this issue?

    Thank you
     
    #10 PanzerFreak, May 11, 2019
  11. Grit

    Grit Senior Member

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    When was the last time brake fliud was flushed and refilled?
     
    #11 Grit, May 11, 2019
  12. PanzerFreak

    PanzerFreak Junior Member

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    Car is still on the original brake fluid. I inquired with a Toyota dealer about doing a break fluid flush and fill last October and they mentioned they didn't think it was needed. However, I've read on here about the Toyota manual recommending it changed at 100k.

    A few minutes ago I disconnected the negative terminal on the 12v, waited 30 seconds, reconnected and then went for short drive. The warning lights were still on but breaking capacity seemed normal again. Weird.
     
    #12 PanzerFreak, May 11, 2019
  13. ChapmanF

    ChapmanF Senior Member

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    Hi ,

    Posting the trouble codes will help identify what issue you've got, which will also help with finding out if anyone else has had it.
     
    #13 ChapmanF, May 11, 2019
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