Could faulty 12V battery be causing dash warning lights?

The car in question is a 2007 Prius with 125k miles.

The issue I'm having is that I took the car out today for a drive and about half-way into my drive the red warning triangle came on as well as the VSC light, the tire pressure light and the check engine light.

I continued to drive for about 10 miles and noticed no issues with drivability. The car drives completely fine and goes back-and-forth between electric mode just fine with no issues whatsoever.

According to the display, the HV battery stays fully charged in the green level most of the time and never gets below the blue level.

When I got home I popped the hood and let the ICE run. I could audibly hear the inverter pump running and when opening the inverter coolant reservoir I could also see the coolant moving as well (which means the pump is working I assume).

The last thing I did was to test the 12V battery. It's a little over 14V when the car is running but when it's in ACC mode it was around 11.6-11.8V. So, perhaps the 12V battery is going bad, but I don't think that would trigger all these warning lights, would it?

Either way, I probably need to take it into the dealership (and I will), I guess my real question is could a faulty 12V battery be causing all these warning lights?

 

I followed this procedure to test the 12V battery:
Weird stuff happening? MPGs dropping? Test The Battery | PriusChat

So while I didn't use a multimeter to test it, the car was off (in ACC mode) when I tested it using the MFD.

I don't know the age of the battery since we've only owned the car for a year, but it should probably be replaced. I'm just curious as to whether this could cause all the warning lights I'm getting.

 

I'll likely replace it just to rule it out.

However, I was under the impression that if that red triangle warning light stays on, it means a code is stored in the system which is something a low 12V battery wouldn't cause. Maybe I'm wrong though?

 

Yeah, I need to get a code reader ASAP!

 

Yes, tire pressure is 40psi all around.

I'll away the Mini VCI and see what that tells me. Amazon says it will be here Friday. Hopefully the software is easy to install on my laptop.

Had to install BMW DIS software once and that was a nightmare!

 

That stinks! My laptop is running Windows 10... I don't have anything else on there however, so perhaps I'll just load a copy of Windows XP or Windows 7 on there.

I was under the impression (and correct me if I'm wrong, since I am mostly a Mac user) that Windows 10 had some sort of Windows XP / 7 emulator mode.

The tire pressure warning light is now off, so now I've just got VSC, check engine and the red warning triangle.

 

Good to know! Problem is I only have a 5K iMac, and while I do have BootCamp on it with Windows 10, I'd have to go through too much of a hassle with the desktop.

I have a spare Windows laptop with nothing on it that I bought for the sole purpose of doing things like this, so I'll have to use that.

As much as I dislike Windows, it's obviously necessary for these sorts of things.

 

That's exactly what I bought this laptop for

 

Bummer... I won't know for sure until I get the Mini VCI, but I think at 124k miles my HV battery is toast.

When I start the car after it sitting in the garage for a few hours the battery is down to one bar (purple). When I start the car it only takes a minute and all of a sudden the battery is 100% full (all green bars). Then I turn it off, go back in 2 minutes and the battery is in the 50% range (blue bars). It keeps fluctuating like this non-stop.

Also, now I can hear the battery fan in the rear going on-and-off periodically as well...

I really hope it isn't the HV battery, but all signs point to that being the case... Ugh!!!

Only 124k miles too... I would have thought it would last me until 200k.