Weird, intermittent indicator lamps (VSC, Battery, Triangle of Doom, "(!)", and Hybrid System) P0A08

I've been struggling with this one for a while and am finally breaking down to ask for help =)

Seemingly randomly, these five indicators/icons will suddenly appear:
Red Triangle of Doom
Yellow (!)
Yellow VCS
MFD Battery
MFD Car divided by an "!"

The MFD will usually say "PROBLEM". Then after some time, the battery light goes away, and after turning the car off and back on, the VSC and (!) lights go off, leaving just the large red triangle of doom and the MFD icon showing the car with the exclamation in it.

Eventually, even those lights will go away as well (sometimes after an hour, other times after a day or two). About a week later, they will pop on again.

First sign of trouble: Lights and icons show up:


After about 20 minutes, the battery light goes away on its own (car hasnt been turned off or on, it just goes away)


after turning the car off and back on (within about 1 hr of the lights coming on), the VSC and (!) have gone away, leaving the triangle and the "!car" icon.



(as I write this, the dash board shows NO lights or icons), but I suspect they will return....
...they always return...



History:
Car was just recently, low-speed rear ended, though I can't recall whether this was happening prior to that or after..

I used an MVCI to look at the codes when it first showed up and pulled the following:


I then did a battery load test and the battery wasn't terrible but I replaced it anyway (with yellow top optima). Seemed like everything was great for 4 days then today -- wham, the lights came back on UGGHHHH

I pulled out my MVCI to see if the lights happen be associated with different codes, but of course tech stream is no longer working (unable to connect to VIM).

I'm not sure what to do at this point. I could take it in, but I'm wondering whether this issue might be related to the accident, and if not/their insurance won't cover it -- how expensive will it be to fix.

Seriously appreciate any help!

 

Thanks Patrick! I can't remember jumping the car anytime recently... a long time ago I jumped a car with it, and may have botched that -- but that was 2-3 years ago. Could it have taken this long to manifest?

The car is a 2005 with 160,000 miles. No major repairs in the past, except I replaced the water pump after it failed and caused overheating.

 

It was the one that is driven by the serpentine belt, held to the block by 3 bolts. I did that one in my driveway, but I think the other one was replaced as part of a recall.

Good idea! I let the car sit overnight then used the "Display Signal"/MFD method to check the battery voltage this morning before I drove the car:

PowerButton pressed once:


PowerButton pressed again, with headlights+highbeams, AC AUTO, front and rear defrost buttons pressed:


PowerButton pressed again, with brake, putting car in ready mode, engine running.


By the way, Patrick and Bisco, I'm searching through threads to learn more about this issue out and I noticed that you both are always jumping in to help other members with their troubleshooting -- just wanted to say thank you so much for everything you do for the members and lurkers of this forum, even when you so often don't get much in return. This forum wouldn't be what it is without members like yourselves =)

UPDATE: Got Techstream working again!
There's a great write up that works for me every time on my 64bit computer (attached to this post)

The only code I see now is good ol' P0A08. I can't seem to find any more information. When I click the little blue icon it takes me to a page called "Freeze Frame Data" with a readout of various parameters.

 

Patrick, I didn't have my voltmeter in the car when it happened today, but will use it to get the readings you requested. However, the light did appear again and I immediately pulled over and used the MFD method. I know it's not ideal but it was all I had at the moment.

The MFD readings were:
ACC --- 12.9v
IG ON --- 11.7v (with Headlights/Defrost)
READY --- 13.8v


When I got home, I hooked up Techstream and did a health check. Same codes as before: P0A08 and C1357.


Here is the FFD for both:

P0A08:
Page 1


Page 2



C1357:
Page 1


Page 2

 

Just wanted to post an update:
I found my DMM, cleared the codes, and will report on the above tomorrow just to make sure I'm not getting biased readings from the MFD signal display method. Once the DTC pops up again, I'll pull over immediately while the car is still in READY mode and report that voltage reading.

Car drives normally, no symptoms whatsoever. MPG is consistency 42mpg, 75% highway driving.
One odd behavior is that when the VSC and (!) indicators appear, I can't use cruise control. Once those go away, I can use cruise control again, even if I still have the red triangle.

 

Well, Patrick - I tried to clear the DTC but it comes back immediately, like I click the erase button and it blinks off for a split second and comes right back on. It used to be more intermittent but now it seems to be sticking around.

Oddly, even though the VSC and (!) lights are on, I only see the single P0A08 code.

Took direct battery measure in the engine bay with DMM this morning after the car sat for the night, before starting the car: 12.61
In ready mode it was 14.08

 

Patrick -- here's an update.
Lights were intermittent (would turn on and off seemingly at random -- sometimes just the large triangle, sometimes all 3 lights) but have now become permanent. Even if I reset the codes, the lights come on immediately when the car enters READY.

Responses to your recommendations:
1.) I basically uninstalled and reinstalled the new 12V battery and cleaned up/tightened everything down. Used battery cleaner on the posts and clamps as well as the ground clamp bolt that goes into the chassis.
2.) Positive battery terminal seems okay. Checked tightness of the bolt and it seems good. Anything specific I should look for to indicate the condition is acceptable?
3.) I am beginning to think there might be some sort of electrical short that was caused (or worsened) when I was rear-ended.

Also -- How do I check the tightness of the inverter cable connections? Is it this:

from: Dredded pa092 error on 2005 prius | Page 2 | PriusChat

 

Oh, I've also been keeping a log of battery voltages taken from engine bay pos terminal to nearest grounded bolt using my DMM:

4-8-16
Light turned off
READY = 14.28

4-11-16
Morning after sitting for a couple days
READY =14.06

4-12-16
After a day on the way home at gas station
OFF= 13.08 off
READY =14.55

4-13-16
cold start lights back on after days being off
READY = 14.1

4-27-16
After battery clean
READY = 14.05

 

I finally gave up and took the car to the Dealership -- after a couple days and a $385 diagnostic charge, they have settled on it being the DC/DC Converter.

They want $1,800 to replace the part.

I called around and got one quote from an independent shop for $5000

I know this is supposedly a project someone like me might be able to do, but I'm concerned about safety risks -- is there a risk of electrocution when swapping the inverter with a used model?

Also, I heard it can be pretty painful to bleed the inverter coolant. I've done spark plugs, oil, and TB cleaning. Is this the kind of repair a person like me could handle?

Any advice is greatly appreciated -- if it's something I should be able to do myself, I'll take photos and make a guide.

 

Looking at some images of the process of unbolting the inverter, I'm wondering at what point the coolant even needs to be changed?

Spring maintenance