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3 Brake warning lights come on - no codes stored?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Confrad in VA, Feb 25, 2017.

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  1. Confrad in VA

    Confrad in VA Junior Member

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    I’m the original owner of a 2006 Prius with 170K miles. Recently the (!) VCS, ABS lights have been coming on intermittently when starting the car. They stay on the entire time while driving (with no noticeable difference in braking). There is no pattern to when this happens – it might be 3 times in a row, then nothing the next 5 times starting. These 3 amber lights are the only ones on.

    I have a brought it to a Toyota dealer when this first started and they said there were no codes stored and to bring it back while it is happening (the closest one is about 45 minutes away, and not very convenient to get to). I have a Scanguage II connected and when these lights come on it shows no active codes, and no codes stored. It’s always the same 3 lights.

    I changed the original 12V battery with an Optima about 1 year ago so I doubt that is the cause.
    Any thoughts?
     
    #1 Confrad in VA, Feb 25, 2017
  2. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Do you have anything hooked up to the OBD port, say a ScanGuage?
     
    #2 Mendel Leisk, Feb 25, 2017
  3. Confrad in VA

    Confrad in VA Junior Member

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    Yes. I've first tried after the lights came on and had shut off the car - no codes stored.
    Then I've had it connected the whole time to monitor - when I start the car and the lights do come on now there are no active codes
     
    #3 Confrad in VA, Feb 25, 2017
  4. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Our dealership suspects a scangauge being constantly connected caused brake warnings to come on, for our 2010. I disconnected it 18 months back, and so far no repeat. Just one possibility.
     
    #4 Mendel Leisk, Feb 25, 2017
  5. Confrad in VA

    Confrad in VA Junior Member

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    I've tried it without the scanguage connected for weeks, same intermittent lights - doesn't seem to matter if it's connected or not. Today I had it disconnected and on first start, lights, returning from golf, no lights, going to store no lights, going to second store, no lights, coming home - LIGHTS! There seems to be no rhyme or reason to when the come on. Id oesn't seem to matter if it's parked for 20 minutes or for 20 hours - no telling when they will come on
     
    #5 Confrad in VA, Feb 25, 2017
    Mendel Leisk likes this.
  6. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    You could try replacing the ABS also know as the Skid Control Computer. I have seen several cars that act absolutely possessed with bad ABS computers. This is a bit of a WAG.

    Brad
     
    #6 strawbrad, Feb 25, 2017
  7. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Maybe try a different dealership (if practical)? It's strange I think, that you would get warning lights, but no codes.

    And brake behaviour doesn't change? With our 2010 there was "check hybrid system" warning, and various brake lights. More importantly I think: the brakes definitely felt different. At first it felt like they were GONE, then you realize they're still working, but sorta back-to-defaults. Definitely less responsive.

    The dealership did recover codes, and concurred the brakes can and do go into a sort of fail-safe mode.

    The also said bring it in when you have the lights, don't turn it off. I did this, and the mechanic came out with laptop with Techstream, did some checks, saw the usual codes. The one thing he point out: he was getting an intermittent connection, thought it might be due to ScanGuage plug constantly weighing on the port. And that this might be the problem.

    Disconnecting SG has worked for me, for 18 months now. But may not be a factor in your case. Guess I'm out of bright ideas, lol. Hope you get it sorted.
     
    #7 Mendel Leisk, Feb 25, 2017
  8. Confrad in VA

    Confrad in VA Junior Member

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    Was it just these 3 amber lights? Not the Red warning light also?
     
    #8 Confrad in VA, Feb 25, 2017
  9. Confrad in VA

    Confrad in VA Junior Member

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    I just did a search and found this...
    "I am assuming i am not the first one to report this issue.
    but last week my prius 2004, 89000 miles, started with the brake light, ABS and warning light on nd rmained so afterwards.
    I took it in for a diagnostic test with toyota.
    the codes read C1311, C1377. as an internal failure at the skid control ECU.
    they quoted parts and labor for $2625."

    My problem is that no codes ever show up, even when I took it to the dealer.
     
    #9 Confrad in VA, Feb 25, 2017
  10. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Here's one shot I could find:

    upload_2017-2-25_13-32-16.png
    (I believe parking brake was on when I took pic, might account for the rightmost light)

    And my notes from the first incident. Keep in mind, this is third gen, so maybe not that relevant:

    ====
    Saturday, August 30, 2014
    km: 46351
    * Warning "CHECK HYBRID SYSTEM" and yellow triangle with exclamation came on, at start up. I was backing out of garage, with light touch on the brakes. It felt for a moment like there was less braking, then the warnings came on.
    * Took it into OpenRoad Toyota Pomo: They recorded and clear codes and test drove, say appears ok now. They say something about "computer loosing contact with brakes" is one of the codes. They advise to just drive, keep an eye on it.
    * Codes: U0129, C2121, C2122, C2123, C2124, 00073, U0293
    * Looking on internet:

    C2121 thru C2124 mean loss of signal from the TPMS sensors.
    U0129 is Lost Communication With Brake System Control Module
    U0293 LOST COMMUNICATION WITH HV ECU
    ====
     
    #10 Mendel Leisk, Feb 25, 2017
  11. Confrad in VA

    Confrad in VA Junior Member

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    I have the previous generation, so dash is a bit different.
    I'll post a pic
     
    #11 Confrad in VA, Feb 25, 2017
  12. Confrad in VA

    Confrad in VA Junior Member

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    #12 Confrad in VA, Feb 25, 2017
  13. Confrad in VA

    Confrad in VA Junior Member

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    I was concerned about not passing inspection (due in March) so I stopped by my local mechanic to ask if these lights would be a problem. I showed him that there were no codes (the warning lights were on at the time). He said that there would not be a problem passing inspection, it would just mean the ABS would not be working - which would not be a failure in Virginia.
     
    #13 Confrad in VA, Feb 25, 2017
  14. ChapmanF

    ChapmanF Senior Member

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    I'd be curious, when those lights are on, how do they blink if you jumper with a short wire between the TC and CG pins on your diagnostic connector? (Search for images showing just which pins those are.)

    -Chap
     
    #14 ChapmanF, Feb 25, 2017
  15. Confrad in VA

    Confrad in VA Junior Member

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    I'll have to check and let you know. I never can tell when they will be on, but I'll have a jumper ready.
     
    #15 Confrad in VA, Feb 25, 2017
  16. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    Yea,
    That's part of the possessed part. The part is cheap at the junkyards. It's a contortion job to install and you'll need Techstream to calibrate.

    Brad
     
    #16 strawbrad, Feb 25, 2017
  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Here are my thoughts:

    1. Have you checked the inverter coolant reservoir for fluid turbulence when the Prius is READY, which shows the coolant pump is operational?
    2. I noticed that the SRS airbag light is on as well as the TPMS light, based upon your photo in post 12.
    3. Why is the SRS light on - was the car in an accident?
    4. Have you checked air pressure across all four tires?
    5. If the ABS/VSC/((!)) lights are on, then DTC have been logged. Are those lights still on when the dealer attempts to retrieve the DTC?
    6. If you want to retrieve the DTC yourself, get Mini VCI.
     
    #17 Patrick Wong, Feb 26, 2017
  18. Shaun_Collins

    Shaun_Collins Junior Member

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    I see the exact same problem intermittiently never any patterns with zero codes on my '06. We keep a Mini bluetooth OBD2/ ELMS327 reader plugged in on vith our '04 and '06 24/7 365. Sometimes power cycling resets the three amber lights but sometimes overnight sitting does. But sometimes they comes back on the next day. Only occurs about average of 6% of the total trips.

    Sent via my LG V20 on Tapatalk
     
    #18 Shaun_Collins, Feb 26, 2017
  19. ChapmanF

    ChapmanF Senior Member

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    Still interested in the blinkage after jumpering TC to CG....

    -Chap
     
    #19 ChapmanF, Feb 26, 2017
  20. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Dumb as I am about such things, this is bugging me too. OP needs to try a different dealership? Or talk directly with the Service Manager?
     
    #20 Mendel Leisk, Feb 26, 2017
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