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Brake/ABS Light & Buzzer Question

Discussion in 'Generation 1 Prius Discussion' started by Linda L, Aug 25, 2015.

  1. Linda L

    Linda L Junior Member

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    I'm also having an issue with these lights/buzzer on my 2002 since last weekend. Probably about one in every five starts, the brake/ABS warning lights/buzzer come on for around five to ten seconds and then go off. Braking appears to be fine. I'm thinking the brake system is taking too long to pressurize on starting. The car has run fine and brakes have worked fine after this has happened. Brake fluid level is fine. Do these warning lights/buzzer usually stay on, with an issue, or is this intermittent lights upon starting how it normally shows a problem? And yes, I am going to see about finally ordering a mini VCI and also read the blink codes. Dealer is 50 miles from home so I'm trying to figure out what is going on prior to heading that way, as I don't want to have an issue on the drive there.
     
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  2. ChapmanF

    ChapmanF Senior Member

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    Hi Linda,

    Good for you on ordering the Mini VCI, and yes, you can read blink codes before it even gets here. (The blink codes are kind of a reader's-digest version of the actual trouble codes you'll get with the Mini VCI, in other words, they don't tell you anything the VCI won't, and the VCI will give you more detail, but the blink codes can tell you now, and even the reader's-digest version is better than knowing nothing about your problem.)

    There's a chart in the diagnostics section of your service manual (volume 1, on techinfo.toyota.com) that shows how to translate the blink codes to the actual trouble codes. There's also a chart there that shows which of the trouble codes light which dash lights, and which ones sound the buzzer. So you already know you've got at least one of the buzzer-level codes, but it's very much worth counting the blinks so you know which ones.

    Your thinking about pressurization on starting is definitely reasonable. The codes that are treated as important enough to sound the buzzer are generally related to that one way or another. Now to just finish pinning down the root cause of your issue.

    In another post I wrote back in March, I ended up describing this exact system in the car a little. The post wasn't about brakes exactly, it was in a thread where someone had commented on the computers in modern cars making them harder to troubleshoot, and I was giving an example of how they make it easier, and it just happened that I picked this exact system as the example. So it might give you a sense of exactly how closely the computer watches over that pressure pump and accumulator, and how detailed an understanding of the problem you can get by retrieving the codes.

    Cheers,
    -Chap
     
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  3. Linda L

    Linda L Junior Member

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    After a crazy week of back to school, finally following up on this. I have decided to order the scan gauge vs the mini VCI and wanted to check that this is the one to get. It seems, from what I have read, to be much simpler than dealing with the mini VCI and a computer. I also like the real time feedback aspect while driving.

    Amazon.com: ScanGauge SGIIFFP ScanGauge 2: Automotive

    After replacing the hybrid battery in the car a few years back, I am in it for the long haul and think a scan gauge will be of great benefit.
     
  4. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Yes but check the PriusChat store too. I can't vouch for costs but any profits will help Danny justify the unGodly hours he spends keeping the site working. <GRINS>

    By my estimation, Danny is working somewhere between $.25-.35/hr while delivering services in the $25-35/hr range.

    Bob Wilson
     
  5. Linda L

    Linda L Junior Member

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    Scan gauge arrived today! I plugged it in and read codes. Only two stored codes were 0420 and p3190, which I have had sporadically before (I guess I finally need to get oxygen sensors replaced). But no other codes than those two, which don't have anything to do with the brakes. Car just passed 200K mileage, hybrid battery replaced at dealer about 2 years ago at 160K. Alarm buzzer is now going off every time the car is started, and brakes got very squishy and slow last time I drove it home.
    Where do I go from here to figure out what is going on with my car? It's in the driveway until this gets solved.
     
  6. ChapmanF

    ChapmanF Senior Member

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    Hi Linda,

    Unfortunately, the ScanGauge is not a complete replacement for a Mini VCI. The VCI can read codes from all computers in the car. A normal OBD-II reader can get the standard emission-related codes from the powertrain. A ScanGauge can read the same as a normal OBD-II reader out of the box, and with some fiddling programming in "XGAUGEs", it can read from the Hybrid-Vehicle computer and the Battery computer ... and those were very important achievements because those are the two computers in the car that don't have any other way to announce their codes.

    The other computers in the car (brakes, steering, cruise, airbag, etc.) obviously can be read over the diagnostic port (after all, the Mini VCI can do it), but as far as I know, no one has yet succeeded in getting a ScanGauge to do it ... these other computers communicate using a different protocol and bit rate, and the ScanGauge "XGAUGE" programming doesn't offer that level of control.

    The good news is: (1) now you have a ScanGauge, and any time in the future when there are issues in the HV or Battery computer that need attention, you will be able to read those codes*; (2) while it won't help you read your brake codes, that's not the end of the world because the brake computer also has a way to blink codes out to you on the dashboard brake light, if you jumper the proper two terminals together at the diagnostic connector. That would be your best bet now, for getting the codes you need to read without prolonging the suspense (and possible risk).

    Cheers,
    -Chap


    * that is, it will be possible for you to read those codes in future if you need to, but easiest if you prepare in advance by finding the threads on "XGAUGE" programming, and keying in at least the basic XGAUGEs for trouble codes and inf. codes, so you won't have to be doing that at the time you want to read something.
     
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  7. Linda L

    Linda L Junior Member

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    Ugh! Wish I would have been warned that the scan gauge couldn't read brake codes when I posted last week that I was going to order it.
    I know the scan gauge is a valuable tool to have, but I would have never spent the $170 right now when I could be possibly looking at a $1-$2K repair. Very frustrated right now. Not even sure I have electrical wire here. But I did find the instructions on the blink test. Anyone know of a good independent hybrid mechanic near San Angelo, TX?
     
  8. ChapmanF

    ChapmanF Senior Member

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    Sorry about that ... I think I was concentrating on getting on the road for the holiday, I may have read your post quickly and probably just didn't really catch that you had said ScanGauge and not mVCI, and it was a brakes thread .... :contrite:

    But anyway, the blink codes are quick to pull and should be informative.

    -Chap
     
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