p0420 code can it trigger code p3125

1. Use the Graham scanner to read out the hybrid vehicle ECU codes.
2. Using the codes, follow their fault isolation steps.
3. Inspect the inverter coolant and pump to make sure working.
4. Inspect and reseat connectors.
5. Worse comes to worse, swap inverters using my spare.

Bob Wilson

 

Great, let's say that you've done all that, and with the spare inverter installed, the codes remain.

What would your next steps be?

 

Put the original inverter back in and begin comparing the "failing" inverter signals against the healthy signals of my own NHW11. I would also want to check the connectors and wiring harness. The ambiguity group has moved away from the inverter and towards something on the vehicle.

Bob Wilson

 

At this point, what would lead you to believe the original inverter was failing?

 

I don't which is why I would return the vehicle to its original configuration and begin a more exhaustive, signal-by-signal investigation.

We treat the "failing" inverter as potentially OK until one or more specific signals between the inverter, transaxle and control computers are found to be abnormal. We then fault-isolate the source of the failing signal. Essentially the ambiguity group expands including the HV ECU, wire harness and connectors, and transaxle.

Bob Wilson

 

Its fair to say that Bob's troubleshooting approach would be an improvement over a typical dealer tech, who would start swapping parts until the customer's budget or patience was exhausted.

 

With all due respect, I disagree.

To begin with, the prejudicial "typical dealer tech, who would start swapping parts" statement can be set aside. Bob himself raised the possibility of swapping parts. You didn't seem to mind.

And as with any profession, technicians of varying levels of professionalism can be found at Toyota dealerships. There is no "typical" dealer tech, just as there probably isn't a "typical" profile for your own profession, whatever it may be.

Many dealerships will give the tech one hour to diagnose the vehicle prior to removing any parts. No diagnosis? No pay; you're paid by the job. Car goes to someone else.

And many dealerships have a policy of not letting the part out of the parts department unless it's attached to a repair order. Want to send a part back? Sorry, dealer tech, you may have to buy that part yourself. Better luck next time.

If the vehicle is under warranty and Toyota is footing the bill, they may be willing to put up with a bit of swaptronix to get the vehicle out the door quickly, if the technician is struggling.

Keep in mind that I'm not criticizing Bob's methods. He's working with what he has. For someone who has time on their hands and little diagnostic experience with this fault, his methods may be worthwhile. But they wouldn't fly in a professional shop. That's reality.

 

Let's say the signals are not failing. What then?

What tools and methods would you use to check those components?

 

Then it is not broke.

Inspection, remote end jumper, and ohm them out.

Bob Wilson

 

Bob listed swapping out the inverter as step #5, not step #1, on his list in post #21. The intent behind steps #1 - #4 was to obtain sufficient information to make the effort to perform step #5 worthwhile. Bob was generous enough to offer the use of his spare inverter. I'm wondering what you would suggest as a troubleshooting method, given the information provided by the OP.

I've seen posts from owners in similar situations where they are told that the Toyota tech wants to replace the inverter, transaxle, and hybrid vehicle ECU, all at the owner's expense. Or, if the traction battery has failed, the owner is told that the tech wants to replace the battery, the battery ECU, and the three system main relays, again at the owner's expense.

I would question whether all of those components really require replacing, or if this laundry list was provided in hopes that the owner will give up, tow the car away and thus relieve the tech of the responsibility of identifying the sole failed part.

 

I disagree. I have seen faulty inverters which would exhibit normal signals during such testing.

That sounds awfully time-consuming. Can you think of a better way?

 

Yes, I'm aware of that. It's still parts swapping. Yet you have characterized the strategy as "an improvement over a typical dealer tech, who would start swapping parts until the customer's budget or patience was exhausted."

How did you come to believe that your characterization is an accurate representation of the typical dealer experience?

I'm aware of that, as well. However, in many cases, such a strategy would not yield sufficient information.

That was very nice of him. However, his generosity does not have anything to do with your assertions.

LOL! You really want the silver bullet, don't you?

Hey, I have no problem with that, but let's wait a bit. I have some more questions to ask about this diagnostic process.

Hint: do not be afraid to question your own assumptions.

I've read such stories, as well. Such an approach is no more efficient than the one cited in this thread. But again, the stories you have read do not establish that the "typical dealer tech", as you say, is bound to do that. For example, I doubt many people think to post on this forum when a diagnosis goes smoothly, unless the vehicle is out of warranty and they are looking for free repairs.

But if you have personal experience across a range of incidents sufficient to support your assertion, I'd love to hear them. After all, we're all interested in accurate information, aren't we?

Most likely, they did not. But again, they do no render your assertions to be true.

My guess is that the average person would have no problem with this kind of diagnosis if Toyota was footing the bill. And believe me, that can happen. However, it would be a poor example of diagnostics and a needless waste of resources.

But hey, my car's fixed, right?

 

I've come to believe my characterization is accurate based upon the number of posts that you can find on PriusChat with similar stories.

Yes, I am really looking forward to learning how you would address this particular issue. You've posed many questions in this thread. The underlying message seems to be that you know better.

Hence, I'd like to see your silver bullet answer. These forums are intended to be a way for owners to learn from each other.

(BTW, do you even own a Prius? This is unclear since you haven't bothered to post any identifying information although you've been a member for almost five years. If you don't own a Prius, what is your source of knowledge?)

 

Great! Would you have one for sale?

It works and I like to know which wire(s) are broken or shorted to frame. If it is just one, try to locate the failure point, prevent further damage, and consider running a new one. If more than one, send a sympathy card.

Bob Wilson

 

If you're looking for inverters that have been diagnosed as failed, you may want to ask around at dealerships in your area.

I'm just trying to follow you here. So after installing a replacement inverter and finding that it does not resolve the issue, you would focus on looking for a wire that is broken or shorted to the frame?

 

I'm aware of that. However, I think your logic is flawed. I doubt people think to log in to PriusChat to report a successful diagnosis.

I know. I'm still asking questions, thanks.

Feel free to ignore them if they make you uncomfortable.

I didn't say that. I have seen a few odd statements, but again, I'm just asking questions at this point.

I'm sure you would. But if I said "I checked pin 37 and found five volts; the new inverter shows twelve volts at that pin", it would be tempting for someone to re-post that and recommend it as a procedure, even though they have no idea if there is a relationship between the measurements and the failure. That's not learning, that's guessing.

I'm aware of that. However, one can't force folks to be open to learning.

Why do you think that is relevant? Is it necessary to own a Prius to understand it or to comment on the discussion?

With all due respect, owning a Prius is not a "source of knowledge."

 

It is highly relevant to understand the background of the poster to help evaluate the usefulness of an answer being given to a particular question.

In the above string, we've been discussing an expedient way to troubleshoot the hybrid system to determine whether the inverter is the failed part or not. I'm interested in understanding the basis of your knowledge in this area.

Is your knowledge based upon Prius hands-on experience where you've had success repairing similar problems, or is it theoretical? If based upon practical experience, was this gained as an owner working on his own vehicle or are you a professional mechanic?

Should you eventually offer a solution we'll be able to guess answers to the above questions, and that will help us assess the value of your contribution.

You offered a recommendation in the following string. The OP had requested information about where to have a Prius transaxle replaced.
http://priuschat.com/forums/generat...ternatives-dealer-repairs-in-los-angeles.html

Your status as Prius owner or not is quite relevant as we consider the value of your recommendation. Here are a few possibilities:

1. You had a similar transaxle failure on your Prius, and were satisfied with the results.

2. You took your Prius to that location for other service, and were pleased with the outcome.

3. You took your non-hybrid vehicle to that location for transaxle/transmission service, and are a happy customer.

4. You are the friend or relative of Bill, the repair shop owner.

5. You are Bill, the repair shop owner.

Would you agree that if your recommendation is based upon your experience as #1, that would have the highest credibility, while #4 and #5 would offer the lowest credibility?

 

I usually use Ebay since it is nation wide. As much as I like the local service centers, I try to avoid using them for anything other their parts department. ... Which reminds me, I need to head over to Decatur and pick up the camber alignment bolt for our 2010.

Hummm, it is a difficult problem, trying to follow a thread with multiple postings. I was trying to answer your specific questions across multiple postings. Rather than compound the confusion, it is probably time to let my part of this exchange come to a quiet close.

The original poster reported an inverter problem. Since then, I'm pretty sure they've taken another approach and I'm happy they did.

Since I prefer to spend my time getting 'dirty knuckles', chatting about fixing a mythical inverter problem is not a good use of time. If you need more details about diagnosis and repair of NHW11 inverters, I'll be happy to post the relevant page numbers from:

• Volume 1 - 2003 Prius Maintenance Manual
• Volume 2 - 2003 Prius Maintenance Manual
• Electrical Diagram pages

Bob Wilson