Transaxle Failure

Yes, I was very hesitant before actually purchasing the transaxle...but I spoke with the mechanic at the dealership and he said that he checked each of the parts individually for the faults since all the different codes came up and the transaxle came up as the part with the failure. Also, it was pretty obvious that the failure was the transaxle because when the warning lights came on the car would vibrate and shutter really bad upon acceleration until the gas engine kicked in and it would also make a really strange noise upon decelleration. With the combination of obvious noises, cars behaviour, warning lights, and diagnoisis of the mechanic I am 99.9% sure that it is the transaxle. I am still going to do more diagnostics myself as I am working on the car. I obtained the toyota factory manuals online which are quite extensive in giving the spefications and steps for testing and repairing each part of the car, so those are helping me out a lot.

I did not get much done this weekend as I was really busy with work. I should have the transaxle this week and Saturday and Sunday I will be working on it all day...so I will have a lot of photos for you after that!

 

Just a quick note...I was browsing through the manuals I bought and found this little tidbit about one of the codes that came up:

"With the power switch's power mode changed to ON (IG),
disconnect the battery. If the key is not in the key slot
during reconnection, DTC B2799 may be output."

I did disconnect the battery and replace it without the key in the slot while I was trying to troubleshoot when the car broke down.

That may be the explanation for that code.

 

The transaxle has been delayed...it will not be here until Tuesday. Looks like its going to be one more weekend before I can get it put in.

Good news is I have a couple more friends who are interested in helping me out with it so I should have plenty of hands to work with.

-Peter

 

I have no done the resistance checks yet. I am planning on doing them tomorrow while I am working on my other car (81' VW Veggie/Diesel Rabbit).

Does anyone know if I need a gasket kit for replacing the transaxle? I guess I could call Art's they would probably know...

 

It is! Well usually. It was nice and warm last week...now it is 29 degrees outside and I am freezing my butt off. I guess it is good for the skiers, keeps the snow around longer.

 

Good to know about the exhaust gaskets...I knew I would need the plug gaskets. I am planning on picking up the coolent and ATF this week.

I am thinking that I am going to remove the transaxle with the engine still in...at least thats my plan for now. The manual I have has pretty clear instructions on how to do it that way, so I am going to try to do that and if it is too hard then I will pull everything.

I have heard it is pretty hard to seperate the transaxle from the engine so that is the only thing I am worried about if I do not pull the whole engine.

 

Yes, I drive up and down the hill every weekend. I take it really easy with the prius though. I am usually coasting the whole way down and there is traffic on the way up anyway.

I took it to the dealer in riverside because I was in that area.

 

Thanks for the advice. I know its going to be a tough job, but I have a lot of help and some good instruction.

I have rebuilt several cars before, so I am not totally green but this is my first hybrid problem.

I am currently training as an aircraft mechanic so I have a couple guys from school who want to help out as well as one of my teachers who is an electrical genius.

I will be sure to keep you guys updated and hopefully I will get this project done without any major problems!

 

I talked to the dealer and they told me that there were no subcodes, just the ones they gave me...

They told me that they checked out each component and came up with the transaxle being the one with the failure.

 

Update!

Lots of news for today:

I started doing some more diagnostics on the transaxle today so I can be 100% sure that I am replacing the correct part.

I did all of the resistance checks and was disappointed to find none of them out of out of limits. My results are in bold:



Speed Sensor
A1 (GCS) - A4 (GCSG) 12.6 to 16.8 Ω 13.3
A2 (GSN) - A5 (GSNG) 12.6 to 16.8 Ω 13.3
A3 (GRF) - A6 (GRFG) 7.65 to 10.2 Ω 8.3
B1 (MRF) - B4 (MRFG) 7.65 to 10.2 Ω 8.4
B2 (MSN) - B5 (MSNG) 12.6 to 16.8 Ω 14.3
B3 (MCS) - B6 (MCSG) 12.6 to 16.8 Ω 13.3

Temperature Sensor
C1 (MMT) - C4 (MMTG) 87.3 to 110.5 kΩ at 10°C (50°F) 156.4k
23.8 to 28.5 kΩ at 40°C (104°F)
C3 (OMT) - C6 (OMTG) 87.3 to 110.5 kΩ at 10°C (50°F) 155.8k
23.8 to 28.5 kΩ at 40°C (104°F)

I then called the dealership again to check with them about any subcodes. When I finally got a hold of someone in the service dept. I was lectured for 15 minutes about how I should not be working on my own car, how I am not allowed to work on the hybrid system, and how I am un-certified and incapable of working on a prius. He then told me how he has been working on hybrids for "38 years" and it took everything in me to not scoff at him. Does he think I am stupid? Hybrids have not been around for 38 years. Wow...

Finally after convincing him that I know what I am doing the guy gave me the subcodes for P0A90 which were 604/605. I know that this hybrid stuff is pretty tricky, but seriously its not like it takes a brain surgeon to understand electricity. Anyway...

After going through my manual I found that the subcodes 604/605 refeer to the transaxle or the battery current sensor. I did not want to pull apart the whole back of the car to get to the current sensor since I was already pretty sure that was not it since there were noises coming from the transaxle after the warning lights came on and if it was only that sensor then it would have just been the warning lights.

Now the interesting part.

I found a seal to be leaking on the back of the transaxle, it had leaked all the way down the back (ATF fluid was leaking). From there I decided to drain the fluids from the transaxle to see what was going on with that. The coolent drained fine, obviously. I then drained the ATF fluid from the transaxle. The drain plug had at least an 1/8 inch of metal shavings stuck to it plus several large 1/6 inch chunks of metal stuck on it. After draining the fluid I filtered part of it and even the fluid from the top of the bucket still had a lot of metal content which leads me to believe that there was a mechanical failure in the transaxle.


I was realived to find the metal in the fluid because it confirmed to me that the problem is absolutly the transaxle. It makes sense now that none of the resistance checks failed since it looks like a mechanical failure not a electrical.



I took photos of everything, but I will be unable to upload them until Monday. I will put them up to show you the fluids and the metal content.


After my conversation with the manager at the Riverside Toyota Dealership I am even more determined to fix this problem. I am looking forward to driving into the dealership when I have completed it and asking him how an "unqualified" and "incompetant" person repaired his hybrid.



I was thinking about sending some of the ATF in for analysis, but since I am replacing the transaxle there is no point. No doubt I will be pulling the transaxle apart one I am done with this project to see what it looks like inside.


Does anyone have any experience with changing the inverter/transaxle coolent? I am wondering how difficult the bleeding process will be when it comes time for that. I have heard that you need to get it right or else it can cause some severe damage.


The transaxle is supposed to be delivered on Tuesday so next weekend is the big event. Hopefully everything goes smoothly!

 

I did take photos of the leak, so I will have those up on Monday. I have only removed the bottom engine covers so far, I was kept pretty busy with the diagnostics today so I did not have enough time to continue pulling the inverter.

I am probably going to go buy the engine hangers, I have a list of things I am going to get from the dealer this week. Although I do have a under hoist which I can prop the engine up with if needed.

Thank you for all of your interest and advice it is good to have support as I am going through this project.