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HELP! 2005 Prius warning lights - told 2 ECUs need replaced and possibly battery assembly

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jchum, May 5, 2021.

  1. ChapmanF

    ChapmanF Senior Member

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    Techstream of course, and other than that there also seem to be a good handful of smartphone apps that know those PIDs.
     
  2. jchum

    jchum Junior Member

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    I just borrowed an OBD2 reader from a friend and re-read the codes and this is what I’m getting now. 082EEA95-E639-4D94-8A1A-5B76BB996049.jpeg 9D4C2D6E-DE0F-48C1-8D46-C09E21AC4857.jpeg 273F278F-C28B-449E-AE4C-CC84A40C274D.jpeg 1857A314-9429-4561-8BA6-DC216F1DE903.jpeg 98F71B67-5BFF-43BD-8D86-DA70767BA8C5.jpeg
     

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  3. jchum

    jchum Junior Member

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    So I have a couple questions.
    1. On the OBDII reader there’s 3 options for the DTCs: Current, Historical, or Readiness. What does readiness mean? Or can those codes be ignored? If I only look at the current DTCs then it only gives me P3000 and P0A80.

    2. Is the free version of Dr.Prius (The battery monitor) enough to get a good idea of the health of the modules? Or is there a better app I should be using?

    3. How do I interpret the results of it? Here is a picture of what I got with the car just sitting idle but do I also need to view it while driving? 41E93004-838C-418C-BBF8-197FAA673204.jpeg
     
  4. ChapmanF

    ChapmanF Senior Member

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    I've never been a big fan of the bar graphs in that app, because of the way they exaggerate tiny differences (look at how the blue ones take the difference between 21 and 23 and make it look like it's a factor of 8 or something). So I mostly try to just read the numbers. But in your photo I can't quite make them out.

    I wouldn't mind if the app deep-sixed the bars and just showed the numbers, clearly. (Or they could do something like have the bars, more dimly, and properly scaled, in the background.)

    Or they could consider dropping the bars in favor of something like a box plot, so it would still focus on the variations, but in a way that gave you more help with judging how significant they are.

    There are members here who regularly work on old batteries and may have more specific things to say about your results than I've got.
     
  5. mr_guy_mann

    mr_guy_mann Senior Member

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    You want to drive the car and see what the battery block voltages do when under heavy charge and discharge load.

    Dr Prius is a nice app (and can datalog to a csv file). Hybrid Assitant is another good app (is free) that can view lots of data from the engine and hybrid sytems. It can also generate very good reports.

    One thing you can do with it is to "force charge the battery" to near 80% SOC. Then turn on A/C and every other electrical accessory and wait until the HV pack discharges enough to start the ICE to recharge. The report will generate a graph of all the block voltages over the entire time and graphs the voltage differential as well (this is what the battery ecu looks at to set the P0A80).

    Posted via the PriusChat mobile app.
     
  6. jchum

    jchum Junior Member

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    How can I export the Dr. Prius app data to a .csv? I've tried searching online but couldn't find anything. The record function wasn't even saving anywhere for me that's why I had to just take a picture of the phone. Do I need the paid version of the Dr. Prius app for this? or to get a better look at the battery's health?
     
  7. jchum

    jchum Junior Member

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    Okay so I was finally able to get the data output from the app as a .csv and am now looking at it on my computer but to be honest I'm not sure what I'm really looking at. I drove my car around earlier at different speeds with the Battery Monitor running in the Dr. Prius app. But, how can I tell from looking at the data when the battery is in heavy charge vs discharge? Also, I've read that it the health of the battery is also dependent on the voltage differences in the modules?-Is that just the voltage differences between neighboring modules or the overall voltage difference? And, do I need to look at the differences in resistances too?
    I've attached the excel file of the data in case that helps.
     

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  8. mr_guy_mann

    mr_guy_mann Senior Member

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    So, look at the column marked "Current"- that is amperage flow from discharging the battery (unmarked or positive value) or charging the battery (negative value). The ecu looks at the highest block voltage and compares it to the lowest block - for that particular moment (or frame of data). If that difference is above a programmed value for more than a programmed amount of time, then the ecu "takes note of" the offending block number and starts to increase the Delta SOC value above 0. If that block keeps getting worse (delta SOC increases) then the ecu sets a code for general HV battery condition and the block in particular.

    Dr Prius does the math of block voltage differentials and displays the result. Resistance values are calculated using block voltage and amperage data- personally I don't see much use in displaying those.

    You have to do a lot of number crunching to find a marginally "bad" block use Dr Prius datalog. Some of your blocks do reach 0.5V difference, but it doesn't look like the same block every time.
    Hybrid Assistant does more of that "data analysis" work for you. Plus you can sometimes flush out a weak block by looking at voltages over a long slow discharge down to a low SOC.
     
    #28 mr_guy_mann, Jun 13, 2021
    Last edited: Jun 13, 2021
  9. dolj

    dolj Senior Member

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    And conversely by doing a "forced charge from low SoC to 80% SoC. If the same block that is significantly low voltage in a discharge test is also the highest voltage block in the charge test, that is a good indicator that one (or both) of the module(s) is bad.
     
  10. jchum

    jchum Junior Member

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    I tried doing a forced charge earlier (car in drive, foot on brake, and push the gas) but it wouldn't charge. Also, when I first turn my car on its almost always on just 1 or 2 battery bars. When I first went to take it for a drive today, it charged up relatively quick by just sitting in idle (the had ICE kicked on right away) but then after driving it around for a bit, going to the grocery, and then coming home, I couldn't get it to ever charge past 2 bars (and it mostly stayed at 1 - even when I tried to force charge it). Also, my overall range for SOC was 32 to 59.
    So are these all symptoms that a module is bad?
     
  11. dolj

    dolj Senior Member

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    Yes, more than likely. Your hybrid vehicle (HV) battery needs attention.

    It would be interesting to see what the Delta SoC value is now. Your OP image shows 0.82%.
     
    #31 dolj, Jun 13, 2021
    Last edited by a moderator: Jun 14, 2021
  12. jchum

    jchum Junior Member

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    On the drive back the delta SoC fell to 0.81%.
    So what is the easiest way to identify which module needs replaced? Would the paid portion of the Dr. Prius app show me?
     
  13. TMR-JWAP

    TMR-JWAP Senior Member

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    You are over complicating the hell out of this. The answers you needed have already been provided earlier in the thread. TOYOTA , which probably has the correct diagnostic tools, gave you a list of codes. They're likely to be pretty accurate.
    Didn't the dealer provide you with a list of DTCs? Thought I saw three that indicated "Block x weak". That should be a good starting point.
     
  14. jchum

    jchum Junior Member

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    I'm sorry I am just very new to all of this and trying to make sense of it all. Yes, the Toyota dealer gave me the DTCs P3000, P3012, 3014 and 3019. But they told me that meant I needed 2 ECUs replaced. After talking with you, you said if it was an ECU it was likely the one inside the HV battery and to check for corrosion. I checked it and it looked fine but there was some corrosion on the battery's bus bars so I cleaned all those and the bolts. After that it drove great for about 150 miles (even had improved gas mileage) but then all the lights came back on. And, when I used my friends OBDII reader with the Dr. Prius app, I am only getting the P3000 and P0A80 codes. So I guess what I'm really asking is, are the P3012, 3014 and 3019 codes something only a high end OBDII reader, like the one at Toyota, would be able to get? I know they correspond to blocks 2, 4, and 9 but since I wasn't seeing those codes come up on the Dr. Prius app I wasn't for sure if maybe that issue was fixed with cleaning the bus bars and bolts and this was something different going on now? Or is my best bet still just to look at those 3 blocks?

    Again, sorry if I'm being difficult I'm just trying to understand it all. But I really do appreciate all of your guys' help!!!
     
  15. TMR-JWAP

    TMR-JWAP Senior Member

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    Sorry if that previous post sounded harsh. I had actually deleted the first part but when I left the page and came back, it showed up in the message again and I wasn't aware of it when I posted it.. I only intended for the second part of the post to be posted.

    The good thing about the Dorman batteries is they tend to not have corrosion in the ECU socket or on the wire harness plug. They do a good job of ensuring they're in good condition.

    The P0A80 will almost always be the first to trigger when a HV battery is beginning to fail. It's more of a general warning and will allow the car to continue being driven normally. Once the car determines more specifically which module(s) is weak, it triggers the specific module code. At that time, the car essentially goes to limp mode.
     
  16. jchum

    jchum Junior Member

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    Okay, thank you, I will look at Blocks 2, 4, and 9 then. As far as determining which module within each block is bad, does my following logic make sense?
    I took all the data from the Dr. Prius battery monitor (from both driving and sitting idle) and organized it in an Excel sheet. I found the voltage differences between blocks for each data point. Then found the minimum, maximum, and average voltage for each Block and each voltage block difference. I highlighted blocks 2, 4, and 9 in yellow since those are the ones I had codes for. Then every time there was a maximum voltage difference of more than 0.5V I highlighted them in orange. Then depending on which side of blocks 2, 4, and 9 these occurred on, I chose the module on that "side" of it and highlighted it in red. So I'm assuming the three modules I highlighted in red are the ones I need to replace. battery voltages.png
     
  17. ChapmanF

    ChapmanF Senior Member

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    Since the ECU only physically has wires to measure the voltage every two modules, you're not really going to come up with any scheme where that can tell you which of the two modules in a block is worse than the other.
     
  18. jchum

    jchum Junior Member

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    So I replaced some modules based on the codes I had and it drove fine for about 60 miles and then the lights came back on. The only codes I am getting on my OBDII reader though are the P0A80 and P3000. One thing I've been noticing when driving it is, on the display screen where it shows the engine and the battery charge, when I first turn the car on the battery usually shows that it's charged (either blue or green) but then within a minute or so of when I actually start driving it, it falls to just one or 2 red bars. It pretty much always charges back up after a few minutes but the charging does appear a bit erratic - it will go all the way full green and then still show the engine charging it or it will drop low but the engine doesn't start kicking in to charge it.
    Any thoughts on this??
     
  19. TMR-JWAP

    TMR-JWAP Senior Member

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    Yes, you still have a bad module in there.

    Let's start with Block 1 being the 2 modules furthest from the ecu. Does that match how you're counting blocks?

    So, starting from the module furthest from the ecu:
    block 2 is modules 3 and 4.
    block 4 is modules 7 and 8
    block 9 is modules 17 and 18

    Unfortunately, depending on what modules you're installing, you may be creating a moving target for yourself. If they are extremely strong modules, they're going to make the others appear weak.

    One reason it takes more than a couple hours to properly rebuild a battery. Time is required for good testing to determine every modules individual capacity so modules matched to the remaining modules can be installed as replacements.

    Read this post:

    Inconsistent Hybrid battery readings | PriusChat
     
    #39 TMR-JWAP, Jun 22, 2021
    Last edited: Jun 22, 2021
  20. jchum

    jchum Junior Member

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    No, when I took the battery apart the modules were already numbered from the dealer who rebuilt the battery before I bought it and they had module 1 as the one closest to the ECU so that's what I went with for the counting. Are different years numbered differently because I read conflicting stuff online about how to count them?