2006 Prius with P0AA6, 614 HV fault - inverter??

Hi everyone, I’ve been reading many many threads and its all been so helpful so thanks to you all! This particular code seems to be rare and the threads on it have concluded in several different parts being replaced or don't have any resolution at all. I would appreciate any insights or advice on my situation!

history of the car:

2006 model, 126,000 miles. I bought it at 123k about 8 months ago. The previous owner took it to the dealer for everything and regular inspections, got the spark plugs changed, tires rotated etc. One thing I’ve noticed from the service records is that the transmission fluid has never been changed, they only “inspected and adjusted all fluid levels” - so I will be having that done soon regardless. Two years ago the HV battery died and she replaced it with an aftermarket battery (at a dealer) which itself died about a year ago when it was still under warranty and was replaced with a new aftermarket battery.

Two months ago I had a red triangle and all the other lights error upon starting the car (after sitting for a few days) and it wouldn’t go into drive. Towed it to the dealer, they said the 12v battery was low (11.9) and charged it and said nothing else was wrong. It happened again so I changed the 12v myself. I also checked the hybrid battery fan (it was pretty clean) and seam sealed some cracks in the roof that were letting water in.

Problem:

Last week I had a red triangle error while driving, pulled over to park it and when I turned it off and back on again, it wouldn’t go into drive. Towed it to a shop and they pulled code P00A6-526, then test drove it 20 miles and couldn’t replicate the error. They also said they didn’t find anything off with the HV battery but I’m not sure what they did to get that result.

I got a miniVCI from Ebay and Techstream up and running (I am using a Windows XP virtual machine on my Mac). Pulled the codes myself to get P0AA6, 526 and 614. This seems to mean that the fault could be in the battery, the inverter, or a bunch of things in between. But not the transaxle. I have the manual PDF that lists the potential places it could be:
•Frame wire
•System main relay
•System main resistor
•HV battery assembly
•Inverter with converter assembly
•Main battery cable
•No. 2 main battery cable
•Battery plug
•No. 2 frame wire
•Junction block

I also checked the inverter coolant pump and it has turbulence. Tried doing the test from Luscious Garage where you turn the car to IG-ON, then neutral, then drive and wait a minute to try and isolate the fault but the lights didn’t come back on at all so it’s inconclusive.

I went for a quick drive while checking the voltage of the battery blocks in Techstream and did not see any outlying numbers.

Questions:

Does the intermittence of the issue point to the hybrid battery even though it is DTC 614 and not 612?

Should I keep driving the car until the error comes back? If I knew it was the battery, I would feel more comfortable with this. But if it is one of the other parts, will it get more damaged?

Any suggestions to diagnose the problem? I don't have a megohmmeter and don't think I would feel comfortable going inside the engine area with live voltage and finding the right parts to test.

I can take it to the dealer but I don't know if I trust them to diagnose this issue correctly. Does anyone know if they are likely to go through all the steps in the manual checking? I know they are not going to open the hybrid battery to look for leaks. Also, if it turns out to be the inverter or transaxle I can't have the dealer do the replacement because I will be getting a used part.

If I knew it would make it there safely, I would take it to Autoguys in Wisconsin as they seem way more experienced with Priuses. Also if I need to replace the hybrid battery they will do it for $1995 vs $2400 from the dealer.

Any recommendations? Thank you for reading!!

 

Thank you PriusCamper! Is it correct to say that you don't think driving regularly right now is a big deal? I have also realized that if the car detects the HV fault as soon as it occurs, if I don't have an error code that means the leak or whatever is not currently "live". So if I brought it to a shop right now they might not even find the resistance problem that would be necessary to diagnose it, maybe.

Yes, I can actually get an OEM battery locally for $1560 plus tax and core charge. My main concern (besides electrocution) is putting the core back together exactly correctly for them to accept. Also it would only have a 1 year warranty vs 3 if I pay for the install. It has only a small chance of failing but that's worth something, plus the cost of tools I would have to get, plus dealing with the core.

 

Thank you! I will try this tomorrow.

 

Yes! It's listed on the toyota parts website at the Toyota in St. Charles, IL. I can post a link when I've got a couple more comments...

 

I did the Shortwave Highest Value test and it was 4.99 the whole time. I will definitely do it again the next time I get the alert. At this point I've driven 100+ miles and it's still acting fine. I think I'm noticing the battery go into the green more often though, so maybe that's a sign that it's getting weaker. I will keep updating as anything new happens!

I could have a shop rebalance my battery with presumably one or two new modules for $400. I suppose I can do that four times over the rest of the car's life and come out ahead. Or I could get into DIY and come out ahead after the second module fix. I wouldn't mind having a later Gen3 for my next car though. Will consider all these options if it comes to that point!

 

Adding some links that go along with my first post-

this is the manual that covers P0AA6 errors

this is the test from Luscious Garage to try to isolate where the ground fault is

here are the instructions and virtual image I used to set up Techstream on my Mac (very easy!)