Inverter /converter or transaxle failure?

welcome!
is the inverter coolant pump working?
how is the 12v health?
what are you reading the codes with?

 

Gen 2 Prius (2004-2009) Transmission Failure, P0AA6, P0A92, P0A7A - Luscious Garage | Hybrid Specialists

may be helpful. They explain how to know it is the transaxle and some common solutions. (none cheap)

 

High volt ground fault. Usually from damaged battery module in the hybrid battery leaking electrolyte and conducting to ground. Car can measure that current flow and throws a high volt ground fault nag.
You can reset it by unplugging the 12 volt and sometimes go for quite a while before it logs again.
Sometimes if you continue to drive it may catch on fire.

But think about how it’s been acting. Low power poor mileage strange hybrid battery behavior it will show 4 blue bars then all of a sudden go to no bars or one purple and then maybe back to 3 blue bars.
Or your in a drive through fast good and the battery tanks real fast to one purple bar.
If I’m close it’s new battery time.

Hundreds of posts about battery replacement and repair, read on.

 

... or the HV battery.

The INF codes will tell you. If you are using Techstream, access the freeze frame data (click on the snowflake icon next to the DTC. You are looking for fields the say Information Code x or Detail Code x (where x = 1-5).

 

P0AA6 is usually the HV battery as trans failures of the winding have been pretty rare. Car would have seen lots of mountain use
and poor fluid maintenance. Most likely it is the battery as i stated in post #4. Very very rare to have an iso fault in the Inverter as you have discovered.

I would have spent an hour taking the battery cover off and seeing how corroded it is in the battery box before attempting and spending $$ on anything else. At this point your just shot gunning which is foolish and expensive.

 

Just wondering, did you have any sub codes for your P0AA6? How's the battery look? Where abouts on the islands are you?

 

You are correct to suspect the transaxle, as INF code 613 points to that area as detailed in the Prius Repair Manual.

The full 18 page work-up for DTC P0AA6 is attached.

There have been a few posts from people who are not professional mechanics who tackled this job. Not sure what level of competence you would need, but search this site for posts. Use the advanced search feature (click into the search box above and then click the "More..." button on the popup) and limit the search to the Gen 2 forums and their child forums.

 

Hey Kiter,

That's good news about the battery, hopefully you won't have to worry bout it for a good while.

My '06 daily driver had a t/a with the same codes when I got it, if you're already somewhat familiar with working on cars it's not too bad a job, the main difference with the prius for me was the extra weight of the transaxle, it's pretty hard to wrestle it around, the thing must weigh close to 300 lbs.

You can either leave the engine in the car and separate the t/a from it (with difficulty) or lower engine and t/a assembly and then separate the two at your leisure (<evil grin/>) - I'm pretty certain having the engine out of the car would make it much easier to change transmissions, but ultimately decided not to have to unhook everything that attaches to the engine, and avoid doing a drain/refill on the ICE coolant system.

It kinda reminds me of changinging an engine in a VW, except there's a few high torque nuts and bolts to deal with, and a subframe assembly, plus it required a few more jacks to be involved and an engine lift (probably could have used a decent transmission jack instead).

 

It's a major undertaking , for sure, probably be 1000 or 1200 to have it done around here by a non-dealership, which provided me enough incentive to do it myself (I've done majority of all work on my vehicles since a teenager); that, and the fact I'm an old fart on a very limited income.

That lift is pretty cool; alternatively, you can rely on supporting the engine from below with a bottle jack and some blocking in a way that you can still get to any bolts that you need to get from underneath, which is what I did - but using a rig like that lift frees up alot of space under the car, I dont' know if there's space above the engine compartment to do that on the Gen2 .

I almost bought a transmission jack, but I already have 2 floor jacks, 2 scissor jacks, several bottle jacks, and a 450 lb. rated roll-around engine hoist, which is what I used to hold the t/a with while removing and replacing.

I think the transaxle / engine assembly is easier to work on when your not laying on your back; there's one of the 8 engine/tranny-mating bolts that is kind of hard to get a good angle on while still in the car, had to use a special 12mm box-end wrench to loosen it. Then it's a matter of finding somewhere to pry at to get that first bit of separation between engine and t/a.

Later edit: once you have all 8 mating bolts off, start at where the blanking plate for the starter was, go around the whole assy., prying it just a bit apart as you work your way around the circumference, once you have a 1/4 inch gap all the way around it should start get easier to progress.

I hope maybe someone else will step in with a better explanation, or some helpful tips.

I'm pretty impressed that you changed out the inverter with no issues, I was quite intimidated when I read I'd have to remove the windshield wipers first 8^) - that being said, I wouldn't wish the job on anybody (T/A swap, that is), especially not as a first major (to me, anyway) project, but if you do end up doing it, be careful and make sure the vehicle is very well supported; and, remember that it is possible that too vigorous shaking, pushing, pulling, etc., while under the vehicle could be the last thing you ever do.

Additional edit: One thing to look out for is the 2 locating-dowels that help align the ICE and t/a when assembling; on the first t/a I pulled the dowels stayed in the engine block, and on the second one the dowels stayed with the t/a, it's hard to remove them with out scarring them up, but they clean up easy enough with a file or some fine sand paper

Got any pictures yet?

 

Good advice from MGpwr. If you want more info on how to do this, my post here has a link to what I found to be the most useful guide for this along with a few tips I added.

 

Not sure about this: it's putting a lot of load on the fenders, maybe ok but who knows. Also, is this to lift or drop the engine? Seems like not much lift as shown, would need to build it up even higher. And then? Heave ho over the front??

Spend the $250~300 and get the right contraption:

 

I believe it's fabricated in a way so that it's transferring it's load to frame members; I think its purpose is to support the engine while the tranny is removed from beneath the vehicle.

 

Ok, that makes sense. I'd still prefer one of those hoists though: engineered, safer, more convenient, and down the road you might really need it, for an engine lift.