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Brake electronic issues

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Mendel Leisk, Aug 22, 2015.

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  1. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Time to pull the blink codes, at least.

    Also, how does the inverter coolant reservoir look when the car is READY? Do you see any fluid turbulence?
     
    #21 Patrick Wong, Aug 23, 2015
  2. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Scangauge still keeping mum. I'll get Toyotas top guns on it Wednesday.
     
    #22 Mendel Leisk, Aug 23, 2015
  3. m.wynn

    m.wynn Senior Member

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    D0H!!
     
    #23 m.wynn, Aug 23, 2015
  4. bisco

    bisco cookie crumbler

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    oh, the double whammy!:mad:
     
    #24 bisco, Aug 23, 2015
  5. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Ok, took the plunge, paper clip in hand. jumped these two:

    Capture.JPG

    Parking brake off, start up with foot OFF brake. After boot up, the word "DIAG" appears in middle, and the right side shows a shifting array of warning lights. On left side, the traction control logo appears:

    Capture.JPG

    And blinks in a pattern: first 4 blinks, then 5. So: 45.

    Any ideas?

    See there's "VSC code 45", aka Vehicle Stability Control.
     
    #25 Mendel Leisk, Aug 23, 2015
    Last edited: Aug 23, 2015
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    So the VSC light is blinking 45? That means a "Malfunction in the electronically controlled brake system" which neither will be a big surprise nor a source of great insight.

    The solution if the code repeats after being cleared is to replace the brake booster with master cylinder (which includes the skid control ECU.) My guess is this will take 3-4 labor hours plus the cost of the part.

    So get ready for a $$$$ bill from the dealer if you have a new part installed.
     
    #26 Patrick Wong, Aug 23, 2015
  7. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    One of the two recalls we had was master cylinder related. Wonder if that counts for anything? Oh well, we'll see.

    Thanks a lot Patrick!
     
    #27 Mendel Leisk, Aug 23, 2015
  8. frodoz737

    frodoz737 Top Wrench

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    Ouch! Wish ya luck.
     
    #28 frodoz737, Aug 23, 2015
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  9. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Some history:

    Nov 09, 2010: purchase date, commence of warranty

    Aug 30, 2013, at 39082 km, recall work: REPLACE BRAKE BOOSTER PUMP ASSEMBLY

    Aug 30, 2014*, at 46351 km : CHECK HYBRID LIGHT ON. STORED CODES READ AND CLEARED:
    U0129, C2121, C2122, C2123, C2124, O0073, U0293

    * Not a typo, one year later, to the day
     
    #29 Mendel Leisk, Aug 23, 2015
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    So from August 2014 until you started this string, you did not have further problems with the brake system?

    U0129 and U0293 both point to a comm problem, another PC member was recently posting about a similar comm issue.

    C2121 - C2124 relate to the tire pressure monitoring system - apparently the sensors were having a problem or needed to be registered.
     
    #30 Patrick Wong, Aug 23, 2015
    Last edited: Aug 23, 2015
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  11. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Tire pressure sensors are fine. The Aug 2014 incident began with a momentary loss of braking. Backing out of garage, suddenly brakes weren't working, then they were, and "check hybrid system" came on.
     
    #31 Mendel Leisk, Aug 23, 2015
  12. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Went for a protracted drive. Was trying to avoid it, but had to. And no lights, no weird brake behaviour. Could the OBD jumper somehow rebooted things, dismissed codes?

    I have "spoke too soon" standing by, lol.
     
    #32 Mendel Leisk, Aug 24, 2015
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  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The process to clear the DTC is supposed to be to connect the jumper between pins 4 and 13, then press the brake pedal 8x within 5 seconds.
     
    #33 Patrick Wong, Aug 24, 2015
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  14. m.wynn

    m.wynn Senior Member

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    Perhaps Mendel was so nervous his foot trembled in way that allowed him to do that chicken dance by accident?...

    Really starting to look like the skid control ECU in that thing is possessed and needs to be exorcised. Question is can it somehow be turned into warranty work, ala failed previous D0H? The plot thickens...
     
    #34 m.wynn, Aug 24, 2015
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  15. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    At Open Road Toyota Port Moody since I brought it in, on time, for 7:45 appt. 9:00 am now, car still sitting outside. Situation normal I guess. :confused:

    Oh hey, that did it, just disappeared into the shop. :ROFLMAO:
     
    #35 Mendel Leisk, Aug 26, 2015
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  16. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Ok, they say they got identical to codes to last year, that's per my post #29. They cleared the codes, and their "best guess" is it's a borderline 12 volt battery. The did do a test on the battery, and dubbed it healthy tho.

    So their suggestion: continue to monitor, and if lights keep coming on replace the 12 volt first, see what that does. Considering winters coming and it'll be 5 years old in in November, I might just replace it in any event, in the next month or two.

    It's been behaving since last Sunday's melt down, nothing since. But it's worrisome: lights come on, coupled with a strange shift in braking behaviour. And a single restart doesn't always clear the behaviour anymore.

    Oh, and no charge for diagnosis this time: silver lining. :)
     
    #36 Mendel Leisk, Aug 26, 2015
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  17. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Ouch, ouch, ouch: just phoned up a couple of parts departments: the OEM Yuasa 12 volt now is $273. Last time I checked, maybe a year back, the one near us was something like $225, and the further afield one maybe $215. The Canadian dollar in action?

    Think I better wait and see.
     
    #37 Mendel Leisk, Aug 26, 2015
  18. m.wynn

    m.wynn Senior Member

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    I would definitely wait and see. At 12.6v after a 24-hour sit, I'd tend to believe you've got a good battery with life left in it. Heck, it may have been sitting at 12.8v this time last year when the car threw the same, wingnut codes.

    I'd be frustrated with how this dealer trip played out. My opinion is this isn't an issue where they should send you off to wait for it to happen again, with the assurance they'll sell you a $300 lawn tractor battery as a "let's see" fix if/when it does.

    Anyhoo, best of luck with it.

    Mike..
     
    #38 m.wynn, Aug 26, 2015
  19. bisco

    bisco cookie crumbler

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    you probably damaged it with all the trickle charging.:cool:
     
    #39 bisco, Aug 26, 2015
  20. CR94

    CR94 Senior Member

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    Expensive compared to other suitable batteries, but a cheap "ouch" compared to an actuator, pump, etc. I hope it's not the latter, but just a momentary electronic hiccup.

    Inability of a dealer to diagnose definitively a potentially serious issue would be exasperating. I've concluded that the brake system, not the battery or HSD system, is the most mysterious and therefore scariest part of a Prius.

    Fluid level is normal?
     
    #40 CR94, Aug 26, 2015
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