01 Prius P3120 P3190 Transaxle Problem

Well, I wish I would have spent more time reading this forum, before I abused my beloved NWH11. I bought her a little over a year ago when it had ~89k miles on it. Since it's mostly a commute vehicle, I've managed to get the mileage up to about 163k. It looks like I made the mistaken of taking a vacation from the bay area to Nevada with the car overly weighted (3 bikes on the back + tons of gear in the trunk). I was in a hurry and pushed it a little hard going over donners pass, and suddenly I noticed I didn't have nearly as much power, and the battery was showing as only being about 1/3 full on the display. I stopped at the next rest stop and let the ICE recharge the battery, thinking that MG2 wasn't running due to low battery. I was very careful after that and drove quite slowly. I made it home, but not without worrying the whole time, and thinking "somthing" didn't feel right... No triangles of death, no indication other than it "felt different" and I didn't seem to have as much power. By the time I made it home, it felt mostly ok.

About 2 months later (just the other day), I was again abusing my poor car, driving about 75 mph, trying to beat rush hour, and up comes the exclamation point, and check engine light, and I quickly loose power in the middle of a 6 lane interchange on the 101 (great fun). I was able to get off an exit by luck and made it to a parking it. The gas was showing I only had one bar left, but it wasn't blinking, and I know I have atleast 50+ miles once it starts blinking so I didn't think I was out of gas, as has happened in the past when I've seen the exclamation (I've always refilled within minutes)... So I again turned on the engine thinking maybe the ICE would charge the battery and I could make it to a gas station, or god would get me out of it or something; so I limped to a gas station, filled up, and it seemed to work a little bit better.

I let it sit for another half hour or so and lo and behold no more Christmas lights. Not only that, it was acting quite normal. I've been driving it in fear ever since.... I knew about the possible transaxle problem when I bought the car (I did some research), but I wish I would have read the whole part about "hills and heat and excessive speed", but it is what it is now...

I took it to the local prius guy, and he said the computer told him the following:

Engine codes:
P0440 EVAP
p3190 ENGINE POWER

HV ECU:
P3120 HV Transaxle Assembly Malfunction
1 Info Code 239 (I've googled this has somthing to do with the crank shaft?)
2 Info Code 204

ABS
C1259 HW SYSTEM REGENERATIVE FAULT

Guess the good news is the battery works fine. The guy said the trans-axle is toast, and needs replacement asap. AFAIK he didn't check the trans-axle fluid as he said he would, but simply declared the trans axle dead. I said, "Would changing the fluid put a band aid on it?) he said, "No, I'm currently only running on the ICE".

Well, I don't believe that is true because I am still getting a solid 45 MPG (even after resetting my computer and driving for several miles)... The computer also shows that MG2 is sending power to the wheels and getting power from the wheels...

I've seen people replacing the stators, and I have a non-prius mechanic I think can do it ok, but I'm wondering if it's really necessary... I've not been able to find anything about the 204 info code....

Any help would be appreciated, and please keep the finger pointing to a minimum, I already feel bad enough for abusing this poor little Prius No. 332

Also, I should note: My main rear seal is also leaking oil and needs to be replaced... Is it possible this has somthing to do with the transaxle/crankshaft problem?

 

It does work fine with the EV only (when backing up, etc...) so that's why I'm really questioning this guys diagnosis. Since I've been reading about this whole "whining" noise, I guess I should have stated that it's been making that noise every since I got the car, so I figured this was a normal thing a Prius did, so I guess I should ask... Don't electric motors whine a least a little bit? It's not overly loud, and you really have to listen for it, but I've put about 60k miles on it with that whining noise, and I've never had any other problems with this car.

Luckily, I live in the Bay area and if it does die, I guess I should have it towed straight to luciousgarage, since they really seem to know what they're doing. Unfortunately for that youtube they failed to show the whole procedure for accessing/disassembling the MG2 (although, they did show it being replaced). I signed up for an all data account and now have access to the blow up views so I'm going to check that and see if my mechanic thinks he can handle it. From the way people talk, this is really a tough thing to do, but it looks pretty easy from the looks of that youtube video...

 

Yep, it works just fine. ICE shuts off at stop lights, and I can drive in EV mode at slow speeds. No overt studdering.

No noises, excepted the minor whining I mentioned. I tried backing up well over 500 feet up a hill, with no problem, no noise. The only thing close to a stutter I could feel was in the first half second of taking off in EV only mode, and I could BARELY notice it.

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Yeah, I'm going to drop the pan and check the oil.. I'll post a picture

 

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The place I took it deals only in hybrid repair, and they have the prius scanners. The codes they gave me were from those. I'm sure they never tested the temp of the motors as they never drove the thing at sort of distance, unless they can pull that from the car with the scanner. Either way, I think taking it into the city is a good idea...

 

So my mechanic friend has drained the ATF and it "looks ok" he says (no overt burning, and still pretty redish, i forgot to take a picture of it but I will, I collected some in a glass jar). I have no idea if the previous owner ever had it changed. So the bad news: There was a fair amount of gunk on the magnet and in the pan (it felt like butter, see pictures below)... It was mostly really fine, but there were some larger jagged pieces of metal in there (enough to prick your finger!)




No idea where the metal is coming from.. Any ideas? I assume since the error code I got related to the HVT shaft, that the shaft or bearings are the source of the problems. Maybe the stator is fine? Would changing the shaft, etc, out be prudent or is it too difficult? I have alldata access, and a traditional mechanic to help with this. Also like I said, the rear main seal is leaking.... Could the two be related?

My mechanic friend is insisting we use a gasket sealer on the cork gasket... Is this going to cause a problem? If so, how? I did buy a new gasket. I also read somewhere about replacing the washers on the fill and drain plugs, but they were talking about a gen 2, should I also change the washers?

Thanks for everyone’s replies so far, they are much appreciated

 

If you want to diagnose the problem yourself your going to need a ODB-II code scanner. I've got a ScangaugeII on the way, which I guess can read/diagnose much more than your standard scanner, especially on preii. As you might know, 1 of 2 problems usually happen with these gen1. Your battery or transaxle may eventually fail; It's hard to say without a scanner. How many miles do you have on the car?

I'm guessing since it's so much hotter down there, if you were doing some heavy freeway driving, it may be the transaxle overheated and you burnt the stator, just a guess tho. Have you ever changed the transmission fluid? I'm afraid the transaxle isn't cheap. Not sure if there are any garages doing the "Luscious garage" (in SF) new stator repair in LA, which can greatly extend the life of your transmission. Check out the youtube video..

I'm praying mine keeps running ok... I'm going to be checking the temps of the motors very closely...

 

So I got a scanguageII and I'm trying to setup the xguages but I don't see one listed for the temp of the ICE.. I see the MG1 & MG2 temp, but not the engine directly... Should I use the engine coolant temp to monitor the engine temp so I can make sure nothing is overheating as Bob said above, "In normal operation, ICE temp > MG1 temp > MG2 temp. But if MG2 > MG1 and there be problems here."

Thanks again for everyone help!

 

Alright, I got the gauge programmed and took it for a test drive. It appears that MG2 is averaging about 5 degrees hotter than MG1. The most dramatic difference I saw was MG2 being about 14 degrees more then MG1, but that usually would happen when I would pull over to the side of the road, they both kept fairly even on the highway. There were a few times when MG1 did get hotter than MG2, but that was the exception. The hottest I saw MG2 get was 158 Degrees (usually stayed around 150 or so), the ICE coolant temp was between 181-188...

Is this indicative that the stator might be starting to burn out? Is there a max temp for MG2 where I should stop and let it cool? Could the coolant passages be blocked or pump be bad? Should I start looking at these things? Any insight would be appreciated...

 

Sorry I didn't specify I was speaking in Fahrenheit, but yes that is the case. I should also note the test drive took about 30-45 minutes and involved both city and highway driving. I'll check out the inverter pump next. I'm broke so I need to keep this car running as long as possible without incurring $2,500 bills for transaxles and batteries. I'm very glad I got that scangauge, I can't wait to check out all my HV battery info and some of the other xgauges...

Thank you so much Bob, you have been incredibly helpful. If you ever find yourself in northern CA, I'd love to buy you a beer