Gen 1 with P3100 and P3125

Welcome new poster. The below info comes from Graham Davies' scanner manual. I presume it is accurate and perhaps helpful.

P3100 - HV ECU Malfunction
3100: 310 HV ECU internal error. Generator PWN Line Connection Malfunction

P3125 - Converter & Inverter Assembly Malfunction
3125: 327 Generator Inverter Current Sensor Malfunction. Open in generator inverter current sensor (V phase sub sensor)
3125: 332 Generator Inverter Current Sensor Malfunction. Generator inverter current sensor V phase performance problem

I have no experience fixing any of these things, but have to guess that all is not as it should be inside your inverter. I hope that additional info gets posted here. Good luck.

 

Did you replace the inverter?

Usually DTC P3125 is resolved by inverter replacement. If you've already done that, then perhaps you still have a wiring harness issue?

 

It sounds like the circular, plug and wires to the transaxle might have a problem, the generator power line. Also, there should be a plug on the front that may be the generator position sensor output. I'd take pains to remove everything you can to access the front of the transaxle and check out the wiring.

Bob Wilson

 

Good point.

You've been advised that P3125 is usually resolved by replacing the inverter. This is not necessarily true for the Gen 1 Prius. Even a cursory look at Toyota's service information for this code will confirm that there are multiple failure points.

You've also been advised to "check out the wiring" at the front of the transaxle. However, issues with those circuits are reported by a completely different code, so I doubt your present issue is there. Again, this is clearly laid out in the service information.

And many well-meaning folks who toss out ideas here are working from paper manuals. Toyota updates their service information regularly, and the online version is the most accurate. Since you're a mechanic, you'll know how to access that information.

You said the "orange plug" at the rear of the inverter was replaced. If so, then someone had to have disassembled the inverter; the part is not available separately, and cannot be switched out without taking the inverter apart. You may want to remove the lid from the inverter and take a good look at the components. Anything loose?

Also remove the circular metal plug at the front right corner of the inverter (two Torx bolts). Make sure the three bolts inside are tight. These connect the generator cables to the inverter.

If those bolts are not tight, that will affect current levels, and the inverter will report that to the HV ECU, and set a code.

 

Unfortunately, not all of the information for this code is in one place in the manual.

Regarding that particular information code, you can find the following elsewhere in Toyota's service information:

"If the hybrid vehicle control ECU detects errors in the PWM signal, it will conclude that there is an internal malfunction involving the hybrid vehicle control ECU or line connections." [my italics]

Great, we have some progress. To review, you had an HV ECU code for a generator signal problem as well as an inverter code for a generator signal problem. Might the broken wire, rather than a faulty HV ECU, be the root cause of both codes?

I realize that others have leaned towards inverter replacement, but rather than guess, I think the sensible thing to do would be to record your data, clear the codes, and see what new codes you have.

How long has this vehicle been sitting without running?

 

In your OP you mentioned the inverter had hit the strut tower during the accident impact. Had you previously removed the inverter cover to inspect for damage? If you see damage then you might feel justified in replacing the inverter with a salvage part.

Otherwise I agree it would be worthwhile to have the DTC read again to see whether new codes have appeared.

 

This may take a little searching but I believe our NHW11s will flash out the vehicle and engine error codes if the right pins are jumpered on the OBD socket. It has been awhile since I remember reading someone doing that over in "Prius Technical Stuff" but it may also be in my repair manuals. I'll check.

If I remember correctly, it won't flash the battery codes.

Bob Wilson

 

I recognize you're not eager to spend $150 for towing your car and accessing the codes.

Given this issue of the immobilizer ECU not recognizing the replacement hybrid vehicle ECU, and jk's suggestion that the broken wire may well be the cause of both DTCs, why not reinstall the original HV ECU and see what happens.

 

I found on pp. DI-464:

1. "Using SST, connect terminals Tc and CG of the DLC3." (SST carries the OBD signals to where you can access them. Details below)
2. "Remove the EMPS ECU with connector still connected"
3. "Connect both terminals of the 1kohm resistor and LED circuit to terminals WL and PGND of the EMPS ECU."
4. "Turn the ignition switch ON."
5. "Read the DTC from the PS warning light."

The diagram show Tc as the 4th signal on the short side of the OBD connector. CG is the 5th on the long side of the connector.

Bob Wilson

 

Are you sure P3100 Is the HV ECU malfunction?

What is P3001 ? I thought that was HV ECU malfunction

 

Hi Colonel, I copied this from the miniscanner manual authored by Graham Davies, and I am confident that he did an accurate job transcribing from his sources. However, "sure" is a word with unique connotations.

P3001 is listed there as a battery ECU malfunction.

I have no doubt that others with direct access to Toyota's technical documents would correct these here if necessary.

 

Tochatihu is correct. P3001 indicates a battery ECU issue. P3100 indicates an HV ECU issue.

 

Hi Dirk,

I have the Same codes as you!

P3125
P3100

Only I have NOT had a collision...

(from this post http://priuschat.com/forums/generat...v-battery-rebuild-2g-cells-7.html#post1153222 )

Any advances?

 

02 - gen 1, TP


HELP !!!!! We have the same problem!!

P3125

I replaced my inverter & inverter coolant pump and same problem, starts and runs but no reverse & no drve

Quest::::

1.) wheres the HV ECU exactly ?
would the HV ECU be the same part as the inverter?

2.) can someone tell me the exact diagnostic procedure info on the P3125 ( I believe from TIS) showing which lines from the HV ecu to the inverter to check for continuity


3.) pls also tell me (with the inverter out) HOW to check the front of the transaxle ? what to use what were lookn for?

The ? sounds dumb but when cars front wheels are off ground they should turn for drve and reverse correct?