'01 transaxle questions

<div class='quotetop'>QUOTE(ozron @ Oct 22 2007, 10:03 AM) [snapback]528820[/snapback]</div>

How long will the car run in "P"? Can you let it warm-up? Does the throttle plate move? What is the SOC show on the traction battery? Is there any indication, without moving, of a charge going to the traction battery?

Note: be sure to put the parking brake on for any future startup tests. This will keep the daylight running headlamps off.

<div class='quotetop'>QUOTE(ozron @ Oct 22 2007, 10:03 AM) [snapback]528820[/snapback]</div>

We don't have enough information to make a call.

What are your options for getting it to a dealer to have them read out the codes?

What make/model of scanner are you using?

How quickly must this car be returned to service?

Bob Wilson

 

<div class='quotetop'>QUOTE(ozron @ Oct 22 2007, 11:03 AM) [snapback]528820[/snapback]</div>

No diagnosis can be made until, at the very least, the trouble code and sub-code are known. And make sure you get your advice from folks who have actually diagnosed and repaired transaxle and/or inverter issues. There's a lot of guessing on this forum that comes off as reasoned advice.

 

<div class='quotetop'>QUOTE(ozron @ Oct 22 2007, 10:56 AM) [snapback]528860[/snapback]</div>

When you swapped the inverter, did you ohm out the transaxle?

So with the swapped inverter, you still don't see a charge?

Bob Wilson

 

<div class='quotetop'>QUOTE(bwilson4web @ Oct 23 2007, 12:03 AM) [snapback]529152[/snapback]</div>

Why would you ohm out the transaxle? And what would you expect to learn?

 

<div class='quotetop'>QUOTE(jk450 @ Oct 23 2007, 05:11 PM) [snapback]529194[/snapback]</div>

I'd want to see each winding has a similar resistance even if I didn't have the specifications. You would need to know which pins to probe.

 

<div class='quotetop'>QUOTE(jk450 @ Oct 23 2007, 02:41 AM) [snapback]529194[/snapback]</div>

Not only to see if all six legs looked balanced but also to check for a winding-to-case short. Ordinarily all stator coils should be open to the case. The manual indicates the proper testing requires a super sensitive meter. But if you are seeing enough continuity for an ordinary, hand held meter to show, then that would a 'dead on' indication that a transaxle replacement is needed.

Bob Wilson

 

<div class='quotetop'>QUOTE(bwilson4web @ Oct 23 2007, 10:33 AM) [snapback]529262[/snapback]</div>

I would expect a DTC in such situations. Have you seen a transaxle with either problem that didn't set a code?

Toyota is correct about the need for a milliohmmeter when measuring specific winding resistances. It's interesting to do, but I haven't yet found a situation in which it helped with a diagnosis.

 

Hi All,

Ohming out the Transaxle will tell you if you have three equal length pieces of wire between the terminals. Which would might tell you if you have a short or not, and definatly, if one of the three coils has burned through a winding (open circuit) . If the resistance between two of the terminal (there three possible combinations per motor) is lower or higher than the rest, this indicates a problem. How much of a difference is permitted should be given in the Prius technical information.

Leakage is important too, but you need a Megger for this. As the Prius has a ground fault circuit, and leakage to ground from the coils I would expect to either trigger it all the time, or every once and a while on voltage peaks.

The main reason to do it is to avoid smoking, or stressing (burning out some link wires to a transitor die - if that is what they are using - but not all) a perfectly good inverter.

 

<div class='quotetop'>QUOTE(donee @ Oct 23 2007, 06:19 PM) [snapback]529447[/snapback]</div>

You would need a milliohmmeter for that. Very few shops will have one, and it isn't needed for diagnosis.
<div class='quotetop'>QUOTE(donee @ Oct 23 2007, 06:19 PM) [snapback]529447[/snapback]</div>

True, but in the real world, the technician needs to be able to figure out if he or she can diagnose the vehicle without a lot of disassembly. Customers typically do not understand the time and money that must be invested in diagnosis (hence the many Prius "enthusiasts" on this forum who throw mud at Toyota every time a dealership charges for diagnostic labor).

Have you successfully diagnosed and repaired a transaxle using the above procedures, and if so, do you think that is the easiest way to do it? What codes were present?

 

<div class='quotetop'>QUOTE(jk450 @ Oct 25 2007, 11:15 AM) [snapback]529986[/snapback]</div>

Especially when they charge $3500US to remove the cylinder head and sump!

 

<div class='quotetop'>QUOTE(patsparks @ Oct 25 2007, 06:56 AM) [snapback]530154[/snapback]</div>

(sigh) DIAGNOSTIC labor. R & R is not part of diagnostic labor.

And yes, just like every other industry, you will find folks in the auto repair industry who will charge too much. That's why they invented the second opinion

 

<div class='quotetop'>QUOTE(jk450 @ Oct 24 2007, 10:45 PM) [snapback]529986[/snapback]</div>

Hi Jk450,

Nope, have no automotive motor drive experience. Have done electronics technician work professionally off and on since I was 18 years old, however. I am in my 50's now.

A miliohmeter and megger are just not that expensive or uncommon. Cheaper than a new transaxle or inverter. Even a 4 wire resistance measurement might work for the miliohmeter part of it. All miliohmeters are 4 wire resistance measuring devices, just a little more sensitive than others. I use a miliohmeter as small part of my professional work. In a pinch, one could probably come up with their own miliohm measurement with a current limiting power supply and a DMM that can measure down into the sub-volt range, or even a DC scope,. An oscilloscope will commonly have 5 mv or better DC reading capabilities. Pump 1 amp through a winding for a few seconds, and 1 mv is 1 miliohm. Not hard, just be sure to put a big resistor and reverse biased diode across the leads to absorb the power down EMF. And disconnect the scope before powering down.

Disconnecting the Transaxle leads would probably be needed for this, or for using a megger. Otherwise damage to the inverter might occur. But swaping an inverter would expose those leads, so he had the opportunity.

The OP does not have access to the codes either. And the device to get a full reading is limited access at Toyota dealerships, right? When one does not have sophisticated diagnosis options, one falls back to the basics that have been used on 3 phase motors since Tesla et al invented them 100 plus years ago.

This guy has time, not equipment to make it go quickly. He desires to turn time into value, even if that is allot of time. Its a different approach than the professional mechanic with the overhead of a 10 bay garage building, service manager salary, and owner proffit to satisfy. He has a garage on the end of his house to pay for, maybe, which he will have to pay for whether he fixes the Prius or not. The codes are primarily going to be of value IF there is something electronic wrong besides the motors. So, finding a fault in a motor without them, is still finding a fault. A fault that needs to be fixed before anything else.

 

I have a Graham scanner and it can provide the major codes from the ICE, hybrid and battery ECU. The problem is the difficulty in replacing it and I have no interest in selling it. So until I get my USB based, OBD reader to provide the same functions with a laptop, I can't let the Graham scanner wander. I'm using it to monitor temperatures this fall to verify my warm-up cycle.

Ozark MO is close enough to my Mom's place in Coffeyville KS that I could make a detour on the next trip. However, I have no plans to head out to Mom's unless I take some time around Veteran's day.

If I can get the USB based OBD reader to provide similar functionality, I'll probably get a second one and offer it and the software as a package. But for now, I've got to keep my project resources closer to home.

Bob Wilson

 

<div class='quotetop'>QUOTE(bwilson4web @ Oct 26 2007, 04:03 PM) [snapback]530606[/snapback]</div>

I love how SOME people actually want to help people on PC. (while others just want to argue with those who want to help.)

 

<div class='quotetop'>QUOTE(donee @ Oct 25 2007, 09:26 PM) [snapback]530524[/snapback]</div>

Great idea for jerry-rigging a quasi-milliohmmeter.

While it's true that meggers are quite common in well-equipped shops that work on hybrids, and are mandatory to isolate ground faults, I've never seen a transaxle that could not be diagnosed, and I've never seen a shop that has a milliohmmeter. Neither does any hybrid manufacturer recommend the use of one. I have a milliohmeter, and I would be very interested in learning about a situation where only a milliohmeter can diagnose a problem, or can diagnose it faster than another method. Always looking. But so far, I haven't seen that.

This may change when, for example, GM's two-mode hybrids start showing up in the service bay.
<div class='quotetop'>QUOTE(donee @ Oct 25 2007, 09:26 PM) [snapback]530524[/snapback]</div>

With regard to the megger, the issue does not sound like a ground fault problem, given the symptoms. Could be, but it's unlikely.
<div class='quotetop'>QUOTE(donee @ Oct 25 2007, 09:26 PM) [snapback]530524[/snapback]</div>

Yes, but he may not have the expertise or equipment to move in that direction. Most who do mention it. And some faults absolutely cannot be found without knowing the code and sub-code. I work with many technicians and engineers, and I know that as an engineer, you may find that hard to believe, but it's very easy to prove in the field.


<div class='quotetop'>QUOTE(patsparks @ Oct 26 2007, 07:18 AM) [snapback]530639[/snapback]</div>

He's been helped already. He's been asked for his codes.

Some transaxle issues can only be diagnosed after knowing the code and sub-code, regardless of the amount of equipment or expertise that the individual has on hand. You can't always take shortcuts.

 

Re: '01 transaxle questions

not sure if you got your questioned answered or not, but i had the same thing happen on my car...

did you recently have your oil changed?

that's what happened to me... the guys at jiffy lube put my air filter in upside down causing all the alarms to go off, check engine, car shudder.... my dad flipped the filter and car started to run and all the alerts went away in about 3 or 4 starts

 

Re: '01 transaxle questions

Those are the same symptoms that my car had and the diagnosis from the dealership came up with the transaxle...