Just the opposite of a runaway Prius, my 2002 no longer starts!

Small world. We live about 4 miles from each other, both have gen 1 with similar problems, both drive Dodge trucks, are about the same age, and pretty smart guys ;-)

Now if we can get his friend to divulge how he made the 280 volt charger out of a PC power supply ( I saw pictures ) we would have quite a catch for the forums.

 

No the Toyota procedure is probably not in error for a typical mechanical person with no knowledge of electrical - this is typical of the mechanics I've ran across at service. Now after 30 years of working with high voltage, I only stated how "I" would approach it.
Voltage is voltage and current is current whether it's in a TV set, a ham radio, or a hybrid vehicle, did you know it's the current that can kill you not voltage? It All depends on the path of least resistance at the instant of contact, and that could be the person working on it. You could touch only the + lead and nothing else and nothing will happen (voltage is there) you become that potential, it's when you get across it from + to - somehow through you when there's a problem, you now create a path for the current to flow.

Now lets do some ohms law, the average internal resistance of a person from hand to hand is typically 800K to 1Mohms. Now with 275V present and you mistakingly get across it, the current (which kills you) would be equal to 275/800,000 = .0003A, not enough to kill, but how about with wet hands? How about with a wrist watch on? Resistance now down to say 10K or so, then it would be 275/10,000 = .0275A or 27.5ma. Still not enough to kill. Thay say at least 100ma needs to flow from arm to arm (across the chest) to stop a persons heart.

Now I have not yet performed this procedure but I would still approach it in this way if the need arises. Been zapped a few times in the past and hind sight is 20/20. Don't care if the toyota procedure says not to first disconnect the hv batt lines from the inverter or not, that's just what I would do. I guess everyone has different experiences when it comes down to this kind of stuff. I always say "If you don't know about electricity then don't mess with it". And most mechanical types I've run into know absolutely nothing about electricity! Maybe that's why AAMCO won't work on a prius transaxle, They already know they can't handle it.

 

I'm not ready to give up on the product but AE support leaves a lot to be desired.

Bob Wilson

 

As P3125 is a DTC, I will assume that you are referring to the information code and freeze frame data.

It's par for the course for AE. When the tool is able to connect, it may display codes that don't exist and/or fail to display legitimate data. Some scan tools will do this from time to time, but AE has a reputation for doing it regularly, regardless of vehicle make.

The product is advertised as being on par with scan tools costing about ten times as much. Not surprisingly, there's usually a catch when such promises are made.

 

You need to get the information code or codes for P3125.

 

This is out of Volume 1, pp. DI-271:

We have history of this problem with TomFreed (check messages late last year.) The Auto Enginuity can not read the information codes. In Tom's case, he eliminated the problem(s) that prevented starting and then ran into a shutdown after a few minutes. This was traced to a temperature signal not being detected by the HV ECU. However, he was able to detect the absence of MG temperature and fix the problem.

So we could list "all the steps" in a table and first work the ones that are likely to cause "immediate" or "delayed" problems:

	Column 1	Column 2	Column 3	Column 4	Column 5	Column 6	Column 7	Column 8
0	vehicle	HV ECU	color	description
1	C4 Converter	NODD 4	H12 4	NODD	L-O	12 V battery voltage will drop and this provides a warning	Di-271
2	Inverter	VB I10 5	H11 20 VB	Y	inverter voltage error	DI-273
3	Inverter	M-GINV I9 6	H11 26 M-GINV	B	"
4	Inverter	M-WU I9 3	H11 6	MWU	G	power PWM	three lines	DI-275
5	Inverter	M-UU I9 1	H11 4	MUU	R	"
6	Inverter	M-VU I9 2	H11 5	MVU	W	"

Do you have pages DI-271 through DI-306, "Toyota Repair Manual", RM957U1?

I've got the run the dogs but this is where to find the road-map. I'll be happy to review these pages later but it may work faster if you have the manual. Then work the problems one-by-one.

Bob Wilson

 

I strongly recommend that this type of diagnosis be avoided. P3125 has dozens of information codes. Many of the diagnostic charts for those codes conclude with "replace XX ECU or expensive component" if no faults can be found.

Those charts also assume that the technician already understands of the system, and is not using the diagnostic charts to learn about the system. Logical steps are often missing from these charts, as it is assumed that the technician will already have thought to perform them when and where appropriate.

 

But many of us are vehicle owners and have time to figure it out. Better still, we can bring 'lessons learned' to the community. Like most things in life, pick two from:

• Good
• Fast
• Cheap

Seriously, if you have information to share, trot it out. But I'm reminded of the good ole boy down in Arab who had the disagreeable barber. It didn't matter what anyone said, the barber was going to run it down. So one day, the boy mentioned he needed a good haircut as he'd saved enough and was going to Rome to see the Pope.

The barber said,"That'll be a waste of money because you'll never get to see the Pope except through a telescope."

The boy came back a couple of weeks later and the next day was in the same chair. The barber crowed, "So what happened? Nothing! Right?"

The good ole boy said,

"Well we were in the square and the holy father came out to bless us. As he turned towards my part of the square, he said something to one of his helpers. About five minutes later, a priest came up and quietly asked me to come with him."

"We ducked in a small door and after walking down a lot of hallways, I came into a beautiful room, the private quarters of the Pope. He motioned for me to come up and I knelt down and kissed his ring."

The barber asked, "Then what happened?"

"Well," the good ole boy said,"he asked with eyes of disappointment, 'Who did your hair?'"

Bob Wilson

 

Although there are dozens of info codes associated with DTC P3125, the suggested trouble areas are either the inverter, the hybrid vehicle ECU, or the wiring harness.

If you towed the car to the dealer to obtain the info code, that would further pin down the nature of the problem. That might help you to focus on certain wires whose continuity should be checked (i.e., a wiring harness problem).

Otherwise, if you believe that the installed inverter is in good condition, I would suggest buying a salvage HV ECU, installing it, and seeing if that helps.

 

It sounds like a ECU problem the only way to know for sure is with a complete diagnosis. Now it could also be the fuel pump it could be a lot of things. But based on your current situation and the fact that you can enter ready mode sometimes I would say its not that likely that its your inverter, i could be wrong on this. Without a proper diagnosis its hard to tell what exactly is the issue.

I would check the engine to see if theres anything wrong, throttle plate, MAF, fuel pressure etc.

 

I already have. Unless he wants to start throwing parts at the car, he will need to get the info codes. Sometimes there are no shortcuts.

I'm sure you are, but I think the guy just wants to get his car fixed.