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2005 Prius runs fine, but has warning lights after sitting

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by PerryThePriapus, Jan 9, 2023.

  1. PerryThePriapus

    PerryThePriapus New Member

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    Hi all,

    I bought a 2005 Prius about two years ago with 124k miles. It now has 142k miles. I have really enjoyed owning it.

    I was away over the holidays longer than anticipated, so it ended up sitting in the garage for roughly 1.5 months. I had not initially planned to be gone so long, and I am now learning it is not good for the batteries to go unused.

    Last week, I returned and started it up and moved it outside. It started fine first try and acted normally. However, when I went on a longer drive the next morning, the yellow triangle ! came on when returning home. I disconnected the 12v battery to reset the ECU, as I figured it was just unhappy from sitting. The light went away and stayed off for several drives. However, today when returning home, the red triangle appeared, as well as the yellow circle !, and the CEL. I tried using an inexpensive OBDII Bluetooth scan tool to check the codes, but it does not find any. There is also a car with an ! symbol on the info display screen.

    I checked the 12v battery voltage via the display screen. It was 13.8v while running, dropping to 11.8v when I shut the car off.

    I would appreciate
    1. Any insight into what this combination of events and warning lights most likely indicates
    2. What type of device I need to read the codes that are causing the warning lights
    3. Any helpful troubleshooting guides that indicate what the different combinations of lights mean, and what else I could check on the vehicle
    TIA!
     
  2. bisco

    bisco cookie crumbler

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    sounds like the 12v needs a charge or replacement, but you'll need tech stream obd software ore a dealer to retrieve the trouble codes.

    there are blink codes obtainable with a paperclip jumper. if you search, you should find some helpful threads
    blink-a-k-a-flash-codes-how-to
     
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  3. Tombukt2

    Tombukt2 Senior Member

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    A shop in town can probably get your codes AutoZone in Menards can probably get most of your codes to get you on track You need to get a code reader that you can kind of sort of depend on there's a whole article in this site to help you as low as 20-30 bucks generally speaking i n n o v a 3120 does pretty good for me and rarely allows me to have to get the tech computer off the shelf these days. 12 volts are very important in this car sitting is one of the worst things for this model even the new ones don't do it If you must I don't know what to tell you you'll be replacing 12 volts often and that's that try to drive the car as much as possible It is not a car to be sitting let your Corolla sit and drive the Prius or the truck or whatever If you're only buying the Prius to drive only when you need good gas mileage and driving your truck and your tractor otherwise the Prius may not be for your family.
     
  4. PerryThePriapus

    PerryThePriapus New Member

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    Thanks for the input guys. I did some more research after making that post, and found out about the Dr. Prius and Hybrid Assistant apps. I ordered a compatible OBDII bluetooth device off amazon (the $13 Veepeak one) as I eventually worked out that the one I already had wasn't able to talk to the Hybrid ECU. I was able to pull codes P3000, P0A80, and P3016. I need to do some more research, but it's looking like I will need to at a minimum replace some cells in my current battery. Any input on how to proceed is appreciated.
     
  5. Tombukt2

    Tombukt2 Senior Member

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    Your picture looks kind of like my '09 in this old of a car just for the sake of not having to reinvent the wheel if you will maybe look at a new battery it's well worth I don't know somewhere around 14,600 price tag to have new cells . There's a lot of playing around in nonsense that can go on with changing individual cells in the battery and the dance that goes along with that can become quite frustrating but if you enjoy that sort of thing have at it just realize while you're having at it the car will be sitting going nowhere generally speaking your batter we will be out apart and you'll be charging individual cells with a hobby charger type device and there's whatever 27 of them to do one by one or maybe 2x2 with the correct charging setup so it can be a lengthy drawn out process note-taking marking tops of batteries blah blah blah If that's your bag by all means have at it there guys that will give away racks of these batteries that they pulled out I'm being one of them I have two racks sitting here anybody can come get anytime they want they've been here for 2 years now I don't expect them to go anywhere people have gotten a lot more wise with their time batteries are made to buy You don't refurbish d cells for your mag light do you No. Ah but these batteries are made for that I don't think so.
     
  6. ChapmanF

    ChapmanF Senior Member

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    In addition to the blink-codes method bisco linked to, which doesn't require any device (but can only get codes from certain ECUs in the car), you can also look in this thread to learn about devices and phone apps that can get you the rest of the codes that you can't get in blink form.

    Gen2 OBD2 app review | PriusChat

    Toyota Techstream on a beater Windows laptop is the go-to solution if you just want to know it can see all the codes, and don't want to do a lot of comparison shopping. But several of the apps listed in that thread can also do the trick.
     
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  7. PerryThePriapus

    PerryThePriapus New Member

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    Thanks for the input @ChapmanF . I was able to read codes P3000, P0A80, and P3016 using Dr. Prius once I found out about that app.

    @bisco - in light of the codes that I was able to pull, could this still be 12v battery related? The codes seem to indicate a HV battery issue.

    Today I pulled out the interior to expose the HV battery. Not too difficult but kind of annoying with all the clips. I also drove the car a short distance while monitoring battery module voltage using Dr. Prius. Screenshot posted below. Both the battery monitor screenshot I posted and P3016 seem to indicate an issue with block 6. Additionally, I noticed when I was driving that block 6 voltage would be higher while charging and lower while discharging than all of the other blocks.

    Questions:
    1. Is there any more information on battery/module health that I should get BEFORE pulling the battery? For example, any tests that must be done in the vehicle as opposed to on the bench. I am inclined to pull the battery just so I can take a look at it to better understand how it is constructed, though I recognize there's probably not much I can do to it without some more equipment.
    2. Is there any way to ascertain overall battery health? If just module 6 is having issues, I would probably attempt to replace just that module. However, if something indicates that overall battery health is poor, I would be more focused on replacement options.
    Thanks everyone

    [​IMG]

    [​IMG]
     
  8. PerryThePriapus

    PerryThePriapus New Member

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    Update: pulled battery. Some corrosion on terminals. Module 6 voltage about 1.25v lower than average. The other modules are much more consistent with one another.

    [​IMG]

    upload_2023-1-13_18-24-36.png
     
  9. ChapmanF

    ChapmanF Senior Member

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    From just what you wrote, I can't tell if you noticed that the voltage monitoring results are for 'blocks' (fourteen of those), while in the battery you see 'modules' (twenty-eight of those, each 'block' is two 'modules'), so a problem with 'block' 6 is going to be 'module' 11 or 12 (or both).

    In your photo, I see X marked on both modules 11 and 12, so if you made those Xs then you already know this, and i'm just laying it out here for others who might come across this thread.
     
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  10. PerryThePriapus

    PerryThePriapus New Member

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    Ah yes, I see. For some reason, up to this point I had thought the two modules composing a block were physically connected to each other, requiring them to be replaced simultaneously. I realize now that was an erroneous assumption.

    Either way, it's one (or possibly both) of the two I marked. Thanks for pointing that out!
     
  11. priusrecon

    priusrecon Member

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    Pull that block and split the individual cells. Load test them separately. Also pull and test several cells around them to get an idea of the general health of the rest of the cell population. Good health is generally in the 6000 - 7500 mA*hrs capacity range, 4200- 5500 is about decent mid range, and much below 4 grand is starting to get into the poor health range. Expect many cells to be in the 40 - 55 hundred range on an older battery. That is not a bad thing.

    Whatever the most prevalent health range of the rest of your battery cells are, replace the defective ones with replacements of similar health capacity.... in other words, if the majority of your cell population is of the 40 - 50 hundred range, don't replace the defective blades with brand new 7500 mA*hr cells, the imbalance isn't the best thing. Use other 40-50s instead.
    Unless you are replacing the entire battery pack with a new one, or all the blades with new ones, you will likely be drawing replacements from a used donor battery, which can be gotten from a salvage yard. Cost me about $200-300 if I remember correctly. It's a good deal cause you can get about 20 to 23 decent cells out of a salvage batt suitable for reconditioning, which is essentially a lifetime supply.

    Once you find your bad cells, first try a reconditioning on them individually, sometimes they can be brought back. Otherwise, pull about half a dozen of the healthy cells from your donor battery and do a reconditioning on those. Then test and pick the best of that lot for your replacements. Just remember, if some test waayy better than your old battery's average, go with the ones best matched to the general state of your battery's health, not with the curve raisers.

    Finally, be prepared to have to go back in and swap more cells after your first repair. Sometimes removing the weakest link exposes the next weakest link once the first punching bag is removed. That link then quickly fails sending you back into the battery compartment again.

    Once your swaps are made, it's important to balance your battery so the computer doesn't reject the transplants. Also, very important is properly torquing the buss bar bolts, which can cause computer to reject an otherwise good battery of healthy cells.
    Lastly, it's advisable to invest in a grid charger/balance reconditioner, and use it every year. A proper conditioning routine never hurts....
     
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  12. PerryThePriapus

    PerryThePriapus New Member

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    While driving my 12mpg land cruiser has been fun, it's time to get the Prius back on the road for the sake of my wallet.

    I already have a small hobby battery charger with an NiMH mode, so I hooked that up to module 11 (the bad module) and am currently charging it at 2 amps. We'll see what the health of that module looks like - I imagine not great since it's the only outlier voltage wise?

    Question: when doing a capacity test, what discharge rate is advisable?

    Question 2: can a grid charger be used to balance the modules (after I revitalize or replace, if necessary, module 11?), or do I have to individually charge each module to capacity? Ideally I know I would load test each cell individually and then charge all to the same SOC individually before pairing, but I would have to buy a lot more battery chargers to be able to do that in a timely manner. Is it possible to just revitalize or replace my bad module and then build a grid charger to balance the whole pack at low current over several days?

    Question 3: when people say load test, what do they mean? Do they mean measure battery capacity (e.g. mAh), or are they talking about instantaneous current delivery ability as a stand in for measuring internal resistance of the battery? I can use the little battery charger I have now to discharge at up to 2 amps to a specified voltage (discharging to 5.4v/module right now), and it will tell me the mAh for that discharge cycle. Is this sufficient to determine capacity or is better to discharge at a higher or lower current?

    Thanks guys.
     
  13. PerryThePriapus

    PerryThePriapus New Member

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    So since I last posted, I got a job on the east coast, "fixed" the Prius the day before I moved across the country, drove it 2000 miles without issue, and have had intermittent POA80/P3000 since.

    To summarize briefly what I (remember) doing in the week before I moved:
    1. Ran every module through 3 discharge/charge profiles using 4 hobby chargers. Used the last charge/discharge to characterize the capacity of each module
    2. Purchased 3 used modules from 2nd life battery and replaced the worst modules from my pack. After looking at the state of the pack as a whole, I decided anything below ~4200mAh capacity (memory is a little fuzzy on this one, but I have it in an excel spreadsheet somewhere) was an outlier and would be beneficial to replace.
    3. Did 2 minute discharge load test on each module to characterize internal resistance.
    4. Reordered the modules to pair high IR module with low IR module in each bank to hopefully normalize voltage drop under load across the pack. Still not sure this was the right move, but this made more sense than pairing based off capacity to me.
    5. Grid charged the whole pack using an LED driver for ~36 hours after reassembling it. This did not go quite how I was expecting - the pack never reached the voltages my research indicated it should, though it did get warm.
    6. Put the pack back in the Prius and drove it to Home Depot to get packing supplies once before it was time to leave.
    As we were pulling out, it did give the RToD / CEL. At that there wasn't really anything I could do, so I just ignored it. I knew that if worst came to worst I could swap it out with the Land Cruiser riding on the uHaul car hauler, but I really didn't want to do that for a number of reasons. In the end, the warning lights went away within a few hours and did not come back until a few weeks (I think??) later.. Averaged over 50MPG on some stretches of the trip following behind the uHaul.

    For various reasons, I wasn't able to drive it regularly for the first few months - just on the weekends mostly - so it sat during the week a lot more than I would have liked. The POA80 / P3000 combo would come on seemingly at random and then go away for awhile, but I was never sure if it was a real problem or if it was just because it wasn't being driven enough, as that's what triggered this whole ordeal in the first place. I just kept hoping it would go away However, the last two months it's been driven nearly everyday, and it's still an issue. A number of times it has come on after getting gas, but I don't think this actually has anything to do with putting gas in the car - more likely the driving conditions that preclude me getting gas.

    I still haven't been able to figure out what can cause a POA80 / P3000 code. Before, it gave me POA80 and also the actual bank that was bad. It's not doing that this time, and the car drives fine. The one noticeable difference is that I've only been getting 39 - 40 MPG, whereas before this whole debacle I was getting 43-45 MPG on average. The other thing I've noticed is that the pack gets quite hot - I don't know if it did this before, as I wasn't monitoring it. I have seem temps up to 127 'F on the center section. If I see this, I will force the fan on with Hybrid Assistant, but I don't monitor it all the time. It's quite possible it's gotten hotter without me knowing.

    At this point, it seems like I have 4 options:
    1. Figure out if there is some way to fix this issue - perhaps reevaluate my modules pairings?
    2. Buy all new modules, or maybe the lithium modules
    3. Keep driving it like it is. It's been working so far.
    4. Buy a new(er) car
    I actually really like this little car. It's pretty old, it's beat up, it's got ugly fading paint, the rear bumper is cracked and the lower grill fell off 3 months into me owning it. I paid $2900 for it 2.5 years ago, and it had already paid for itself in gas savings before the battery gave out. Additionally, it netted me $1000 in mileage reimbursement when I moved across the country. I've driven this thing up sand dunes. I've ripped through arroyos at 50 MPH. I've had a full size couch in the back with the hatch open. This car owes me absolutely nothing. I'd like to fix it if I can. I like that it's dirt cheap, and that it's still pretty efficient after 18 years of use. I like the efficiency of being able to rebuild the battery pack to get the full lifespan out of all modules.

    I'm not sure I really had a point to all this, but I had some time to troubleshoot it tonight (ended up cleaning the battery fan, it was fairly dirty) and I had been wanting to update this thread so as to not leave it without conclusion.
     
    #13 PerryThePriapus, Aug 26, 2023
    Last edited: Aug 26, 2023
  14. Tombukt2

    Tombukt2 Senior Member

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    Basically I have the same situation you have going on here maybe 3 years on the car in $2,000 cost for the car 4 months 90 days something like that after purchasing the car I went ahead and got a new battery because I could get one from Toyota for like $1,400 after the transaction was done online I had very similar problems that you were having or are having now The minute the battery was changed all that nonsense went away I mean like permanently or so far anyway it's been about I don't know now close to 2 years and the '09 is boringly boring nothing ever goes on the only thing this car still does and I know when it's going to do it and I know what to do to stop it is when I first start the car in the morning sometimes my speedometer won't light up but I'm watching when I push the button the minute I push the button I can tell that my display is not going to light so I push the button again shuts everything off I wait two seconds something like that step on the brake push the button again and the whole display lights up just like it's supposed to this has been going on since I've owned the car I've had three different displays in the car from low mileage takeouts to 500,000 mi takeouts from other vehicles they all act the same way so I'm thinking it's my car not the display I didn't even waste time with cookies and INF codes and all that nonsense I just figured at that time I had like a 13-year-old battery 10 is pretty normal so on and so forth it just made sense. Rather than spend weeks and months trying to figure out whatever I just got a new battery that seems to be the weak link when it gets aged.
     
  15. mr_guy_mann

    mr_guy_mann Senior Member

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    You can use Hybrid Assistant to perform a "capacity test". In short you force charge the HV battery up to 8 bars. Then start the test on the app - turn on A/C to full cold - high blower. Turn on all 12V loads - lights, rear window defroster, etc.

    When the state of charge gets down to about 45%, end the test. Then go into Hybrid reporter and have it make you a report (use the default settings). In particular you want to find the graph of module voltages- see if any go "significantly" higher or lower than the others.

    Dr Prius is also useful for monitoring block voltages - it gives you a "voltage difference" data line (anything above 0.3V for more than a few seconds can be problematic). It can also data log.

    Another option is to read this thread that reviews several scantool apps and devices. A couple can retrieve freezeframe data and INF codes - this could help give you more information about what the battery ecu "saw" (block voltages) when it set the P0A80.

    https://priuschat.com/index.php?posts/3290690


    Posted via the PriusChat mobile app.