Issue w/ Transaxle Needing to Replace Tranny?

Hi Michael,

"M62" is MG2, which is the motor generator in the transaxle that turns the axleshafts via the differential.

DTC P3009 means that your car has a high voltage leak. Normally the high voltage is isolated from ground. When this DTC comes up, this means that a component is allowing high voltage to leak to ground, which can cause a serious safety issue.

DTC P3000 means that the traction battery or traction battery ECU is having a problem.

I suggest that you inquire into how the tech determined that MG2 is causing the leak. Did the tech use a megger (which is a high voltage ohmmeter) to isolate the failed component?

Other potential trouble areas include the traction battery, the traction battery ECU, and the inverter. Those parts would have been covered by the 100K mile hybrid system warranty which apparently recently expired.

One place where you can obtain a good list of Classic DTC is at www.ecrostech.com where you can find the Prius miniscanner owner's manual. That manual contains a list of DTC at the end.

 

I have nothing specific on this but will be watching from the sidelines as usual. Hoping very much that Toyota agrees to replace the transaxle under warranty, as this appears to be indicated.

I have no negative thoughts about your shop in Van Nuys, but want to mention that yonder east in Claremont (near Pomona), Claremont Toyota has my favorite Prius techs in the area.

Please keep us posted, and good luck.

 

Thats not making alot of sense. Are they saying there was a coolant leak inside the trans and that shorted out the windings? Or there was a coolant leak of the inverter/trans cooler and the trans over heated destroying MG2.The latter would require you driving for quite a while with the check engine light on. Yes? Unlike most cars thats a very bad thing for a Prius.
Yes first thing I'd do if I was the Toy tech is the ohmmeter test too. It's quick & easy. Disconnect the 3 phase inverter drives to the MG's and test each to ground. All 3 Should be meg ohm open to ground. But any high impedance to ground trot out the megger but if its a low impedance to ground short its a dc short and you a done deal to the tune of maybe $5000. Replace MG2..hey I'm here..might as well replace MG1 too. It will get expensive.
Sounds to me like you have one of the very rare trans axle motor winding failures. Unless you were driving with an empty inverter coolant tank (throws a DTC nag=Check engine light)) or driving with no WS fluid in the trans axle Toyota may weigh in with some participation.But here's what I don't get.I know they didn't pull MG2 apart so how do they know its contaminated by coolant? Thats a big job and there not going to do it on a diagnostic fee spec mission so there talking out there a@@. Unless they opened the trans fluid dump hex bolt and coolant poured out. Which may be a first. Give us some follow up please. More numbers. History of car. State of tune. Last transaxle fluid change etc. Thanks and good luck!

 

Hi Michael,

It sounds plausible that the transaxle has failed; however I had not previously heard about a coolant leak as being the cause for such failure. The dealer will probably quote a ~$6K repair bill. This is a big amount to spend on a 2002 considering its market value.

An alternate solution is to install a salvage transaxle; however you have no assurance as to the remaining life of a used part.

If you decide to have the dealer replace the transaxle, you may want to ask the mechanic to verify that the transaxle is the failed part by doing as Ed suggested - disconnecting the AC cables to MG1 and MG2, and measuring the resistance from each of the three MG terminals to ground. I suggest that you be present to observe.

It would be interesting to see if Toyota helps you with the repair cost. I doubt that you will receive help since the powertrain warranty expired at 60K miles. I have noticed that Toyota seems to be less generous than in the past with regard to helping with unwarranted repairs - perhaps this is due to the financial strain that all of the auto mfrs currently face with weak auto sales, exacerbated by the decline of the US$ vs. the Japanese yen.

 

It may be too late but getting about a cup of transaxle oil sent to PdMA for analysis could report:

• coolant in the oil
• particle counts
• types of wear materials

So you didn't hear a rumble that was speed related?

Did you possibly clean the engine compartment with a wand sprayer?

Bob Wilson

 

I just had the Transaxle problem myself. Driving along and the lights all go on. I pull over turn off the car and then it won't turn back on. Call Toyota and no one knew what was happening and what the warning lights meant.

My car is a 2005 with a whole 16,000 miles on it. Toyota will replace the transaxle sice car is less then 3 years old. I also got the extended warranty for the next 4 years. It's been over a week now and this Sat will be two weeks they have my car...only my car salesman knew it was an electrical problem.

 

Just two MGs:

1. MG1 - this small, 18 kw, 24 hp is the brilliant part of the transmission that handles 'gear ratios' using a power-split device, a planetary gear set.
2. MG2 - this large, 33 kW 44 hp is the more 'traditional' motor of the pair. It also handles the regenerative braking.

Head over to the technical forum and find a link to John's page and Graham Davies pages. I've also written a minor piece about some of the unique 'overdrive' operations (to borrow Hobbit's term.)

The reason I asked about cleaning the engine compartment is a small vent hole is located near the firewall that is difficult to reach. However, if you cleaned the engine compartment while it was hot, the water could cool the terminal block enough to 'ingest' enough of the soapy water to trigger the fault. This would be a false positive and relatively easy to correct. But this is not in the 'SOP.'

The little vent tube is a rubber part and it is also possible that it might have 'gone missing.' If so, the probability of water ingestion goes way up:


In the past, a transaxle failure has also been associated with windings shorting and 'rumble' develops that is speed related. However, you didn't mention a 'rumble' so that is why I asked about this alternate diagnosis.

Of course, you could have a failed transaxle and the first documented coolant leak into the transaxle. One clue would be loss of fluid from the plastic resevoir next to the inverter. Patrick Wong may have some photos showing what to check.

Bob Wilson

ps. How about updating your profile with City/State and model information. I saw your signature but this would make it a lot easier for folks to understand what you've got.

 

Hi Michael,

I am wondering why the battery DTC code came up. I have not heard of coolant leakage as a reason for a transaxle failure before. Your post #10 indicated you did not feel confident that Keys techs diagnosed the system thoroughly. You might have another problem instead of, or in addition to the transaxle.

For example, another southern CA owner had a similar problem and the first dealer diagnosed a failed transaxle. She took the car to another dealer to obtain a second opinion, and that dealer diagnosed a bad battery ECU. The ECU was replaced, and all was well.

Therefore, I suggest that a second opinion would be worthwhile. Longo Toyota in El Monte might be a good place for a second opinion since they are a high-volume shop.

The amount that you owe on the car is irrelevant to the repair decision (as you are on the hook to repay the loan whether or not the car is repaired.) Having valid carpool stickers is the main reason to repair the car, assuming that you can take advantage of the solo privilege during your daily commute.

 

Hi Michael,

I would suggest that you fully describe the symptoms and warning lights that you have seen, and let them come up with a diagnosis. There's no need to muddy the water with the first dealer's diagnosis.