DIY Gen 1 MG2 Replacement P3125 P3000 P3009 P3191

That is one very toasty winding in that stator. It's curious that only one burned up like that, I haven't seen a lot of electric motor failures but those I have seen were completely burned up. To me that suggests failure of the enamel insulation and arcing to the stator core, I hope this is not a time bomb that starts to affect all Gen 1 cars. Looks like a major undertaking to replace it.

 

Hey Markus, I am replacing the MG2 stator in my 2003 Toyota Prius and I have one question and its about the ring or shim on the end of the Armature. When you put it back in did you put it on the Transmission lip or did you put it on the Armature before you installed the armature back into the Stator. I am having a hard time getting the Armature splines to align back up with the transmission side. Where did u

 

Hey Big, when you installed the ring back on of the armature did you put the ring on the transaxle part of the transmission or did you put it on the Armature and then put the armature back into the Stator. I having a hard time to get the splines to line up and tried putting the stator in so far and couldnt get the splines to line up and tried putting the stator all the way in and putting the armature in and still havent got it yet. I noticed the ring I dont know if its a shim or a thrust bearing but if you put it on the Armature it fits loosely and I afraid it might some off when the armature goes in so fast from the magnets. So what best to put the ring on the transmission lip or put it on the armature. I put some transmission fluid on the ring to try to hold it place a little better while putting the armature in.

 

I have a 2002 prius that I replaced the MG2 in. During disassembling everything the resolver bolts were removed(I know!). The wheels moved forward when the transmission was placed in "R" after reassembly. I replaced the entire cover with a salvaged cover after trying for hours to retime the resolver. The problem is that the wheels still spin forward in reverse rather backwards. Any ideas what could cause this?

 

So which way does the car go when in:

• "D" - forward or reverse direction
• "R" - reverse direction, so in "R" is still goes forward

Bob Wilson

 

In "R" it moves forward.
In "D" it moves backwards, but it almost seems like the electric and gas motors are fighting each other. I don't know if that's even possible, that's just how it seems.

 

The resolver controls the timing of electric pulses to the motor windings down to 1/4096 of a revolution, if I remember right, so it isn't just about whether the motor runs forward or backward (which requires a fairly large error), but also how well or poorly it does so. So yes, it should be easy for resolver misadjustment to make a motor that runs badly, as if stuff is fighting stuff. I would expect that to be the usual symptom of a slight misadjustment, where only with a considerably larger error would it outright change the spin direction.

-Chap

 

So then is it possible, or perhaps rather is it probable, to retime the resolver?

 

To the best of my knowledge, Toyota does it at the factory (it would not surprise me if oscilloscopes and Lissajous patterns are involved), and then says "don't touch that". I am not aware of any instructions that even exist for field adjustment. I suppose with enough determination and the right instruments a person could get it sort of close, at least close enough that the motor goes the right way around. Getting the efficiency of the factory setting would be a lot to ask, I'd guess. But there might be some EEs here who would find it less daunting, or an interesting challenge.

-Chap

 

First of all, just to rule out the obvious, are you absolutely positively 101% sure that the U, V, and W phase wires are in the right order on all connections both inside and outside, and on the inverter?

Secondly, if the big notch in the outer edge of the resolver is centered exactly on the plug hole in the casing, then the timing should be close enough for the motor to run normally, but maybe with a slight loss of efficiency. This can be checked and adjusted with the transmission fully assembled, by removing the plug bolt from the casing, and by loosening the resolver mounting bolts if adjustment is necessary.

You can see this at about 1:00:15:

 

I have tried to readjust the original resolver to no avail(always moving in the wrong direction). I also removed the cover again with the sole purpose of checking that the phase wires are connected to the correct places. I was truly hopeful that that would be the issue, better to be an idiot than to have an unusable vehicle.

 

I have not heard of enough cases like this to know the next most likely cause of the problem, so I will just throw some suggestions to you. You've probably already thought of these, but you never know:

- measure impedance through the three stator loops
- check error codes with TechStream, reset, and see which ones first pop up again
- check the output of the inverter with a phase rotation tester and/or an oscilloscope
- check resolver connectors

I hope the faulty motor did not damage the inverter.

 

Resolution. . .
I went ahead and swapped out the new motor with a used motor and now the wheels spin in the right direction. I'll be getting with Dorman to try to get my money back.

 

Thanks for the follow-up T3chtonic. This might help someone with the same problem someday.

Do I understand correctly that this was a "new" Dorman brand stator (without rotor)? Did you test or find any indications for the fault besides it running backwards?

 

That is correct.
And no I didn't have any indication other than that. It wasn't throwing any codes either. Unfortunately I bought this item from rockauto.com and they won't return the money because it's been longer than 30 days. There is a manufacturer's warranty though so I can at least get a new, hopefully functional, part.

 

thanks for the info, you guys are great ☝️

 

Well, it's time for me to tackle this task.

My MIL thru the CEL P3191 and today the car limped home.

OP, by chance do you have the O-ring part number?

 

Success!

CAVEAT

1. GEN1, '01-'03, you must remove all four bolts on sub frame to allow it to drop enough to remove and install the STATOR.

2. Take care, and note the inner Needle Bearing, it will dislodge when old stator is removed, try to make sure it is pretty centered or when you start it will make a horrible noise until it settles in, so do not worry if you missed this step, just be mindful where it is sitting before assembly.

3. To seat the stator, get a big plumbing plier and grab that ridiculously sharp shoulder behind the outer bearing, turn it and it will find it's happy place. I tried removing and turning as suggested above but that darn magnet is too darn strong or I am a pathetic weaklin.

TIS Readings: 5X5, she be happy at Delta SOC 20%, Charging at idle 58% SOC. 12v Battery Happy 13.87v. All banks 16+ volts

Went into D,B Reverse no problems , Found the Chunks of PINK SLIME in inverter coolant, need to flush both coolants in anycase, Oh the Joy. Ended up replacing the the Water Pump.

If you need the o-ring, it is readily available at the Dealer

Inverter, a trick to disconnecting the d-side round connector, there are two sneaky tabs under the cap. just look straight down and you will see it. Small screw driver made short order of releasing that sucka.

OP, Thanks for pointing me in the right direction.

Overall, I say this job was a 9.5 due to trying to figure out how to lower the stator housing low enough. Job itself was a breeze. 5.5 out of 10 in difficulty scale.

 

Hello, new to the forum and helping out my neighbor with this repair. We are still waiting on the part, but I did wanted to check on step 12. Unfortunately I did remove the 3 bolts before seeing this post. What would be the best way to time the speed sensor? Thank you!