Dashboard Lights ON: Red and Yellow Brake, ABS and Slip + Beeping + Noise in Engine Bay

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by andreimontreal, Dec 15, 2019.

  1. andreimontreal

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    My Prius - the car that keeps on giving ...

    Today 27km on highway, driving normal, got off, went under this train bridge, climbed a short steep segment and waited at red light. My dashboard began beeping and four lights came on: red and yellow brake ((!)) signs came on, along with ABS and slip light.

    Weather: cold, freezing, just rained last night and there were icy patches around - not sure if I stepped on anything slippery.

    Went out and heard these noises - kinda like the brakes when they get ready, notice the two tones: one high pitch, the other lower.

    It stopped on its own in a few minutes. Went to my destination since I was so close. I'm not sure, I was so pissed I can hardly remember some details, but pumping the brake pedal might've made it stop - I really don't know. I was moving a bit and pumping the brake to test it a lot. Might have - not sure. After it stopped, I was pumping the pedal and the slip sign came on as I floored it.

    My brake pedal feels softer - although it stops very well. I have this feeling that it's easier to floor it.

    The only "issue" under the hood is that I have a little bit of brake fluid over the max level - I poured to much my self. If that matters at all, I wouldn't think so - ever.

    If you have something else besides check the codes and take it to a dealer or mechanic, let me know. I'm listening :cautious:.

    PS: all you anglos what's the word to describe that noise in the 2nd video?
     
  2. Grit

    Grit Senior Member

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    :ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO:
     
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  3. The Electric Me

    The Electric Me Go Speed Go!

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    Sorry, but brakes are a safety issue.
    So if anyone has a problem with them, my advice is always to have them professionally checked out.
    I'd just feel really, really horrible, if I gave any other advice, and it lead to an accident or worse.

    I'm pretty conservative with advice about Brakes, or Tires.
    So I'm going to say, "Check the Codes, and Take it to a Dealer".
    Stay Safe. Good Luck.
     
  4. andreimontreal

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    Agreed. That's the part I know so that's why I said none of that.

    I was wondering who has been in this situation and what they found out.
     
  5. davecook89t

    davecook89t Active Member

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    I'm not sure I can help, I was curious about the noises, but I can't open the link. Maybe post it to Youtube?
     
  6. andreimontreal

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    It is on youtube, maybe I fudged the link.

    I also noticed - not 100% sure - that maybe my abs is not working. Usually in slippery conditions I would get this rolling, jagged action going under the brake pedal; I thought that was my abs. After these lights came on, I had to run a short errand and we got a bit of fresh snow and in slippery conditions I can actually slide. I have no light on the dash - so not sure what's up yet.

    Honestly, I prefer this to the bull abs crap (that almost got me into an accident when I bought the car, I was on this icy slanted road and the abs kept me creeping towards another car at the bottom although I could have stopped with regular brakes). My foot is usually light enough that I get a sense of where the braking limit is; maybe I should learn to deactivate abs for winter.
     
  7. Tyrese Persad

    Tyrese Persad New Member

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    Good day everyone,
    I’m having the same exact problem but my traction, abs,brakes light and also a yellow exclamation are all remaining on the dash.
    Any advice??
     
  8. andreimontreal

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    It seems that it's the brake actuator failing but my research is not conclusive. I think the guy who wrote that is in the US and Toyota did repair his brakes for free.
     
  9. Grit

    Grit Senior Member

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    If taking it in for reading CEL code is not an option then you can either:

    Drive it without proper brakes til you cant stop and get into an accident

    OR

    Throw random brakes parts at it until the light goes away, which could add up to couple thousands and might not even resolve the issue
     
    #9 Grit, Dec 20, 2019
    Last edited: Dec 20, 2019
  10. andreimontreal

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    Don't assume. I told you it's not the case.
     
  11. davecook89t

    davecook89t Active Member

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    I was able to use the link you provided above to hear the sounds.

    I have not yet experienced an ABS actuator failure, but have been concerned that it may eventually manifest itself on our Gen 2 car, since this has happened to many cars of that generation as they age. In the case of the Gen 2, I know that Toyota had issued a Technical Service Bulletin that authorized local dealers to repair failing ABS actuators and bill TMC, if the car produced a certain set of error codes that were indicative of actuator failure, but the program ended as of Dec 31, 2018.

    The sound in your video that repeats at intervals of 15 to 20 seconds does sound to me as if it could be the ABS actuator trying to pressurize the system. It sounds similar to that our Gen 2 makes, but that is far less frequent, the time interval of that can be measured in minutes. The other sound in the video sounds similar to that our Coolant Heat Storage pump makes after the car has been shut down, but I believe that system does not exist on the Gen 3 car (unless it was still part of the Canadian model, not sure). If your actuator is failing (or in your case it could be the accumulator, as I believe that is a separate unit on the Gen 3), as would be indicated by the frequent attempts the actuator is making to pressurize the system, there may be a separate TSB that would apply in your case. Perhaps @Mendel Leisk or @Tideland Prius would know if such a TSB is in effect in Canada. @ChapmanF would be able to help you understand the nuances of the ABS braking system in the Prius.

    In any event, I'm sure that all of them will tell you that you need the codes in order to get any help from Toyota. If you are unable to acquire a copy of Techstream, it may be worthwhile to pay the dealer's diagnostic fee, if you can get assurance from one of the Canadian members that it could be fixed for free.
     
  12. Grit

    Grit Senior Member

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    All of them, and all of us are just assuming. Best to save your words, see post #10.
     
  13. andreimontreal

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    That's exactly what I'm going through right now. I'm 95% sure it's all about some failing brake/abs actuator. Various people with the same behavior confirmed it. Like the link above - in the USA I've heard of later years being repaired for free; I hope I find out more about Canadian cases - either way - Monday I'll be calling around.

    You can assume and guess anything car related - if you have sound reasoning, it's worthwhile. But don't assume things about me. I said not to bother with mentioning the dealer and codes because I'll end up there granted, it was on my least; I know how to do that. What I don't know is DYI options - if any - at all - ever. You're killing me ...
     
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  14. dig4dirt

    dig4dirt MoonGlow

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    no obdii dongle either? wonder if dr prius or torque can read brake/abs codes, no?
     
  15. ChapmanF

    ChapmanF Senior Member

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    a piece of wire can read the brake/abs codes (in abridged form).

    Frequent running of the pump can reflect pressure not holding well, which could mean an internal leak somewhere, which could be either in the actuator assembly or in the accumulator assembly (as davecook89t hinted, they are distinct assemblies in Gen 3). Codes by themselves may not help you localize a leak into one or the other assembly; a mechanic's stethoscope might, or active tests in Techstream, or a combination of both.

    Like a house's well water pump, frequent running of the pump can also mean some of the gas charge is lost from the pressure vessel.

    But how frequently the pump runs also depends on what use you're making of the brakes; in stop-and-go traffic, hearing the pump frequently is to be expected.
     
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  16. andreimontreal

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    Starting yesterday I hear it every time I depress the brake (5 seconds Buzzing Noise every time I depress brakes)- which is not the usual (I noticed it only when I entered the car).

    Do you have any idea if air bubbles in the master can cause any issues or lead to a failure in the brake actuator? I wouldn't think they're related. I'm thinking that the pump and accumulator are like any other compressor system, and that the braking action uses the air from that compressor system to put pressure on the hydraulic lines.
     
  17. sam spade 2

    sam spade 2 Senior Member

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    What you think is "solid reasoning" might not be at all.
    Computer controlled systems often defy simple logic.

    We see evidence of time and money wasted on here almost every day........by people who think they are making an educated analysis.......when it really is just a wild guess, often based on incomplete information.

    And if you mean Do It Yourself (DIY) options, there really aren't many EASY ones except for routine maintenance.

    People in forums like this will usually give you an honest opinion.
    They aren't always pretty.
    If you can't take the heat.............:whistle:
     
  18. ChapmanF

    ChapmanF Senior Member

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    The pump doesn't compress air (directly); it pumps brake fluid. The brake fluid is pumped into an 'accumulator' that also contains trapped nitrogen. The nitrogen compresses, thus brake fluid stored under pressure. A good analogy is a house's well water pump and pressure tank. The accumulator has a bellows meant to keep the nitrogen on one side and the fluid on the other, so they don't mix. The nitrogen charge is intended to be 'permanent' (= as long as the bellows lasts).

    Like a well pump system, any loss of gas from the pressure vessel will mean the pump runs shorter, more frequent cycles.

    Gas bubbles in the hydraulics can have weird effects. In a simpler brake system, usually you could tell when gas was present, because your brake pedal feel would be mushy, and with big enough bubbles, it would be hard to stop.

    The Prius system doesn't behave that simply, because it has active feedback control. The computer decides what fluid pressure it wants to send to each brake, and it has a sensor telling it the pressure at each brake. If there's a gas bubble in a line and the pressure doesn't get to the target right away, the computer will just hold the valve open longer to let more fluid into the line until the bubble is compressed to the target pressure. That happens too fast to notice. So instead of giving you a kind of progressive mushiness that lets you know there are bubbles in your lines, Prius brakes tend to go on feeling more or less the same until they don't. (That's one reason they're wrapped in so many layers of sensors and warning lights and buzzers, other ways to warn you of trouble since you can't count on how the pedal feels.)

    Out of all the brake problems that get reported on PriusChat, a very rare few of them fall into the "floored-pedal-no-stoppie" category. It's good that those cases are so rare because of course they're highly undesirable.

    My speculation about them is that they would result from progressive growth of gas bubbles in the lines, maybe from a slow bellows leak, producing generally no change in brake feel until finally growing large enough to trigger the ECU's safety mode where it had to let so much fluid into a line it now thinks there's a leak there and gives up.

    But that's my speculation; it would take a lot more evidence gathering that I have no way of doing before it could be anything like a conclusion.
     
    #18 ChapmanF, Dec 21, 2019
    Last edited: Dec 21, 2019
  19. andreimontreal

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    Fair enough - there's always a possibility especially with electronics.

    I can take anything Sam. Even Grit's nagging. Silence, letting someone know that nothing can be done further until scanning or letting the person know that the advice is just an opinion is enough. Like I said before I wish I had been told about Toyota's failing brake actuators and their recalls ... all that nagging did nothing for me.

    EDIT: Oh-ho-ho this is massive: Gen3 brake recall program - I wish I had the mini vci right now.
     
    #19 andreimontreal, Dec 21, 2019
    Last edited: Dec 21, 2019
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  20. Tideland Prius

    Tideland Prius Moderator of the North
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