Circled yellow exclamation point in parentheses only

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.

 

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.

 

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!

 

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.

 

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...

 

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.

 

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.

 

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.

 

Just to say it - with your support, I am pretty optimistic Thanks for the offer of interpreting those codes, I appreciate that!