p3030 after successful rebuild/recondition of HV Battery & new ECU

Discussion in 'Generation 1 Prius Discussion' started by Bruce Berquist, Nov 30, 2021.

  1. Bruce Berquist

    Bruce Berquist Junior Member

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    I am honestly hoping that somebody will take the time to read my trouble description here and give constructive feedback.

    I have reviewed all of the archives I can find on this subject but have found none that actually covers my situation. So I hope this post will be read.

    I just rebuilt and reconditioned and balanced my HV Battery in my 2003 Prius sedan.
    I also replaced all of the terminal rails with new ones.
    And due to burnt corroded pins and a p3001 code I replaced the HV Battery ECU.

    The car runs fantastically and everything operates exactly as it is supposed to including MG1 and MG2 transmission etc..

    At first I had the pleasure of having no trouble lights and no codes. But after a 60 mile run, while I was sitting in my driveway reviewing ODBII live data, the triangle and engine light popped on and my scanner found p3030 and p3006 SOC imbalance. Now p3030 won't go away.

    I did a reset of the ECUs by disconnecting and reconnecting the 12v Battery (which has great voltage and passes the load test).

    Live data shows that Block 19 is reading very low voltage.

    So I got back into the battery assembly and reviewed and tested everything, Cells, Bus Bars, Tightness of fasteners, Terminals, Sensor wire voltage and continuity..

    Everything tests good.

    All 38 cells test individually at 8.2v +/-. Healthy. Including cells 37 and 38 of block 19.

    I rigged up a video recorder to watch my multi-meter voltage reading for block 19 while I drive the car.

    While live ODBII data is reading low 9v to 12v in block 19, my multimeter recording was showing that there is no such low voltage happening. The block is running at 16.1v to 16.5v.

    This has me concerned and a bit confused and frustrated.
    I am trying to pass NH safety inspection but the inspection station techs say that the state won't allow them to sticker a car if any trouble lights come up on the dash, even though they have already passed it for emissions and safety, and these lights are only battery related.

    It seems to me that The HV Battery and Hybrid System is functioning and running just fine. I am just getting false sensor readings.

    I am going to get back in and remove these new terminal/sensor rails, and give them a very in-depth inspection for flaws, breaks, and resistance issues.
    I seriously suspect that I won't find anything, but I hope that I do.

    Does anybody have any ideas as to how I can stop these false readings and trouble lights
     
  2. 2010moneypit?

    2010moneypit? Junior Member

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    I know it’s a lot of work but maybe change the cells to a different block and see if the problem fallows the cells. Is the harness OK? I have seen some problems with the connector in the harness.
     
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  3. TMR-JWAP

    TMR-JWAP Senior Member

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    Ok, so what is a P3006 code on a Gen 1?
    Now what is a P3030 code?

    Now, what makes sense as being the easy answer to the above codes? That's where I would start. Probably in the area of Block 19. Just make certain you're looking at the real block 19, not block 1. Remember, block 1 is where the heavy orange cable connects to the negative terminal of a module. The answer should be somewhere between block 19 modules and the ecu socket.
     
    #3 TMR-JWAP, Dec 1, 2021
    Last edited: Dec 1, 2021
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  4. dolj

    dolj Senior Member

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    What was the state of the mating plug on the harness? You may need to meticulously inspect it using a good magnifier.
    Even so, something screams a problem with the harness, just as TMR has said.
     
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  5. Bruce Berquist

    Bruce Berquist Junior Member

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    I replaced the rails (harnesses) on both sides of the battery with brand new rails, that includes the terminal to the ECU.

    Today is my project day for this, to inspect it for the 4rth time in a week.
    But his time, I am pulling the entire harness and putting it on my workbench for a thoroughly complete inspection and testing.

    Can't rule out that a brand new harness could have a flaw in it, and even though I have inspected and tested it 3 times already.
     
  6. Bruce Berquist

    Bruce Berquist Junior Member

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    Thanks! I forgot to mention that I did swap out blocks, when I was retesting everything, in order to see if the problem follows. Nothing changed.

    Also, though the OBDII readings are showing low voltage in Block 19, multi-tester reading reveal that that is not so. The voltage is consistent with all of the other blocks at 16.4v+.
    Multi-tester readings also show that Block 19 discharges and charges consistent with all the other Blocks, so the issue seems to be a sensor issue with Block 19 providing false readings.
     
  7. dolj

    dolj Senior Member

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    I'm talking about the wiring harness that is bolted to every other module terminal that terminates at the orange plug, not the metal bus bars that connect each pair of modules together, which is what it sounds like you're talking about.
    This confirms a fault somewhere between block 19 and the battery ECU.
     
  8. ammdb

    ammdb Member

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    Assuming you got used parts that are new to your car, and not brand new from Toyota, then there might be an issue with the sensing harness or the ECU. Have you checked the resistance of the sense wire from block19 to the connector pin? You can also reinstall the original ECU back in the pack to see if that makes a difference. As I recall this can be done inside the car.

    PS, I used GC Electronics, Dry Clean contact cleaner, which really did a great job cleaning the ECU connectors from the junk battery I purchased as a core -- made it good as new!
     
    #8 ammdb, Dec 1, 2021
    Last edited: Dec 1, 2021
  9. AlexY

    AlexY Member

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    I think you replaced battery ECU having corroded connector to faulty ECU. There is one voltage measurement chip in ECU and number of optically isolated "switches" that connect particular battery block with voltage measurement chip. Probably one of the "switches" is not fully closing the circuit. I would recommend trying your old ECU if you still have it.
     
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