Circled yellow exclamation point in parentheses only

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by John Dadmun, Apr 13, 2022.

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  1. John Dadmun

    John Dadmun Junior Member

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    2009. No symptoms. Went out to check it again & now I've got a low tire pressure indicator. I have a bad seal on one tire so, that shows up about every 3rd morning whereupon I put air in the tire. So in this instance there is no relationship, at all between the two indicator lights apart from their both being yellow. The two symbols aren't at all similar, it is interesting that in postings they get confused. The indicator I am troubleshooting is the "Circled yellow exclamation point in parentheses" indicator. I have read the previous postings on this indicator. Looks like I need my brakes checked? Dr. Prius finds no codes. Haven't tried OBD Fusion yet. Could it be telling me to change my oil though, or something like that based on time? If anyone might advise, I would appreciate it.

    IMG_5991.JPG
     
    #1 John Dadmun, Apr 13, 2022
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  2. ChapmanF

    ChapmanF Senior Member

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    Yes, that's a brake warning light (specifically, the Electronically Controlled Braking or ECB warning light). That's a 'brake' icon because the 'parentheses' are little bitty brake shoes (even though the same icon is used on cars with exclusively disc brakes too).

    One way to find out why it is on, if your scan tool won't tell you, is to use a short jumper wire between two pins of the car's diagnostic port (Tc and CG, you can search here for other threads about that), turn the car on, and count the blinks of the light. You can count them out into two-digit codes and post them here.

    If more than one light on the dash blinks codes out when you do that, you can count out the codes from all of them. Be sure to keep track of which light blinked which codes.

    Any light going into a steady, unbroken, fast blink just means that particular light doesn't have any interesting codes for you at the moment.
     
    #2 ChapmanF, Apr 13, 2022
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  3. Stevewoods

    Stevewoods Senior Member

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    It's a brake warning light, but what it is warning ???

    The first thing to do is see if their are any trouble codes -- but if you don't have a code reader....

    Easy thing is to check if your parking brake is on,,,,but seriously could be anything from parking brake to TPMS to brake actuator.
     
    #3 Stevewoods, Apr 13, 2022
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  4. ChapmanF

    ChapmanF Senior Member

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    If you don't have a code reader, then you use the jumper wire method and get the codes that way, and then you know why the light is on and what it is warning.

    The parking brake, I think you will find, lights a different light, usually the word BRAKE in red.
     
    #4 ChapmanF, Apr 13, 2022
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  5. John Dadmun

    John Dadmun Junior Member

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    No codes according to Dr. Prius app. I mean going into special features on the app & reading HV battery codes & engine codes, nothing found. Am I using the app right, I don't know, seems like it. I have another app code reader, OBD Fusion, that might find something, haven't tried that one yet.
     
    #5 John Dadmun, Apr 13, 2022
  6. cyberpriusII

    cyberpriusII Prodigyplace says I'm Super Kris

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    Without the codes, if there are any, we could all speculate all day....but...

    Isn't the tire pressure light also on....could it have something to do with a failed TPMS??

    And, to quote Forrest Gump -- That's all I am going to say about this -- unusual for me, huh?
    kris
     
    #6 cyberpriusII, Apr 13, 2022
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  7. ChapmanF

    ChapmanF Senior Member

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    The OP is pretty confident the brake warning isn't related to the TPMS warning, because the latter has been coming independently of the former.

    I'm pretty confident they're not related, for a different reason, because at one time or another I've looked through most or all of the brake system codes listed in the repair manual, and don't recall seeing anything suggesting the brake and TPMS are in cahoots. (Could there be a code in there that's slipped my mind. Sure ... I guess I'd bet lunch, but not a real expensive lunch.)

    With any luck, the OP will be back soon with the codes, and then we'll know what the warning's about.
     
    #7 ChapmanF, Apr 13, 2022
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  8. John Dadmun

    John Dadmun Junior Member

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    I just went out to try the OBD Fusion app via the wireless OBDii reader, only to find - no symbol on the dash, no brake shoes parentheses, only the tire pressure sensor remains since I've not pumped up the tire. Something in the brake system temporarily threw an alert? Well I appreciate the idea of counting lights, if it returns I have that option. Thanks for the ideas I appreciate it! (y)
     

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    #8 John Dadmun, Apr 13, 2022
  9. John Dadmun

    John Dadmun Junior Member

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    So the OBD Fusion app found nothing, looked for codes, it was working just didn't find any. But then I ran the code reader after the indicator had already cleared so, would it have found anything? I don't know. It came on just into my commute home, & for several starts thereafter. Gone now for the past 3 starts. I do get a fairly persistent P1121 or I think P1120 code, pushing it a little on long uphills. I just plug in the code reader wireless plug, open the app & clear the code each time lol. I should probably replace that 3 way coolant valve rig-up that is triggering those codes.
     
    #9 John Dadmun, Apr 13, 2022
  10. xliderider

    xliderider Senior Member

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    I've had the brake warning light, or ABS warning light come on if you hit a patch of gravel or pothole when the brakes are applied.

    The light then goes away after a while when the ECU realizes that the error condition is no longer present.

    Posted via the PriusChat mobile app.
     
    #10 xliderider, Apr 13, 2022
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  11. PriusCamper

    PriusCamper Senior Member

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    Seems like spending $30 on a mini-VCI dongle and installing Toyota Techstream on an old windows computer might be the best way to confirm the lack of error code?
     
    #11 PriusCamper, Apr 13, 2022
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  12. PriusCamper

    PriusCamper Senior Member

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    I think you're referring to the the traction control light, not the ABS light...
     
    #12 PriusCamper, Apr 13, 2022
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  13. John Dadmun

    John Dadmun Junior Member

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    Okay, I will look into that... All of those old computers have been Linux'd, I wonder if I could get it to run on a macbook under Parallels...
     
    #12 John Dadmun, Apr 14, 2022
  14. John Dadmun

    John Dadmun Junior Member

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    Looks like your lights blinking method is the most reasonable path forward in figuring out what is wrong. Hoping to look up the 'jumper wire method' on here later today. This morning the brake indicator light came on again, as before just the yellow circled exclamation point in parentheses. Stayed on for the whole commute. I could detect no issue with the braking, but I don't doubt that something is up. I have hit mud pits putting the Prius in it to the floorboards 3 times recently, had to churn out of one backward for quite awhile. It was weeks ago, but perhaps something was damaged.
     
    #13 John Dadmun, Apr 14, 2022
  15. dolj

    dolj Senior Member

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    You sure can. You can use VMware as well.
     
    #14 dolj, Apr 14, 2022
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  16. John Dadmun

    John Dadmun Junior Member

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    Interesting/scary update - finally getting around to putting air in the tire I opened the hatch looking for an extension cord. Strangely there was a liquid laundry soap bottle in there, with no cap on it. Why would there be an empty bottle of laundry detergent in there. Because it wasn't removed along with all of the other groceries, bounced around and emptied into the back hatch area. Right where the brake control module is. I've cleaned it up but, can't account for most of that soap. I guess that it has all drained out now - but I suspect that the error light i am seeing was caused by the soap. I should pull all of this apart but, hesitant to mess with it.

    IMG_6002.jpg
     
    #15 John Dadmun, Apr 16, 2022
  17. ChapmanF

    ChapmanF Senior Member

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    There's a brake emergency power supply box back there, next to the battery. The brake control module is under the dash.

    Do you still have the ((!)) light? Got the codes yet? Then we'll know.

    There's always the light-blink method, if you don't have a scan tool handy that does the job.
     
    #16 ChapmanF, Apr 16, 2022
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  18. John Dadmun

    John Dadmun Junior Member

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    Wow, I hadn't thought to actually see whether the light had gone out. Just drove down my street & back, it is in fact now out! & incidentally the low tire pressure light, also out since I checked all tires & filled the low one. That is so cool!! Clear instrument panel again! Yes, that brake box that you mention, had soap all around the bottom of it & slightly on it. Amazing that just wiping up that soap, seems to have solved the issue.
     
    #17 John Dadmun, Apr 16, 2022
  19. ChapmanF

    ChapmanF Senior Member

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    We can be cautiously optimistic, anyway. That one thing happened after another won't always mean it happened because. So don't be too shocked if the ((!)) comes back; just read the codes and post an update. On the other hand, the longer it stays away, the more optimistic you can be.
     
    #18 ChapmanF, Apr 16, 2022
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  20. John Dadmun

    John Dadmun Junior Member

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    Just to say it - with your support, I am pretty optimistic :) Thanks for the offer of interpreting those codes, I appreciate that!
     
    #19 John Dadmun, Apr 16, 2022
  21. PaulDM

    PaulDM Active Member

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    Wheel slip indicator? Normal function is it flashes when driving over slippery surfaces and combines with an engine brake.
     
    #20 PaulDM, Apr 16, 2022
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