Help! I bricked my wife’s Prius! (HV Battery Swap Gone Bad)

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by PriusToadRVer, May 10, 2019.

  1. PriusToadRVer

    PriusToadRVer Junior Member

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    Warning - long thread. Please wait for multiple posts before replying.

    Background - I’m a retired computer systems engineer. In 2008, we bought my mom a new Prius, and when Mom passed, my wife inherited it. So, a “one” owner, low mile (70K) prius driven gently by two classy mature ladies, 100% dealer maintained, never an electrical or mechanical problem. (We’ve towed it on a dolly behind our RV since 2014, so the back wheels are higher mileage). A few months ago, we noticed declining mpg and occasional, worsening park-green-start-purple events and startup (ICE only) hesitations. I called our respected dealer, and they confidently predicted a relatively near future death triangle event (and no offer of any goodwill or discount on a OEM new battery). I decided on a DIY pre-emptive HV battery replacement before we head for the hinterlands, and to spend a few extra $ on a “Gen 2 Battery Rebuilt From Gen 3 Cells”. I then started driving, testing, and “excercising” the Old battery while waiting for the replacement battery. This is when the confusing and frustrating stuff started....
     
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  2. PriusToadRVer

    PriusToadRVer Junior Member

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    Now, this sounds a bit arrogant, but it’s literally true that I have design, engineering, diy maintenance, rebuild, and/or repair experience on bicycles, cars, trucks, boats, computers, small and large airplanes, and I’m safety trained and certified on electric railways on 3 continents. So a Prius HV battery swap should be a walk in the park (with a little help from my friends at PriusChat), as I glibly explained to my wife and other skeptics.

    The first bit of confusion - the old battery system started behaving noticeably better exactly while I was on the phone placing my order with the battery vendor. Why does Prius HV battery life/performance depend a bit on driving style and test history? First, everybody knows that the closer the mechanic, the more intermittent the problems, right?.

    Next, I downloaded Dr. Prius (iPhone, beautiful application) and plugged in my ELM327 for some in-depth testing. The OBD connection seemed a bit flaky, but a quick email exchange produced “Apple recommends a network reset for reliable WiFi elm operation”. A bit confusing because I use it reliably all the time in non-Prii. It did then produce lots of test results, but no bad module suspects, or other signs of imbalance.

    So, how can I estimate the useful life left in my old battery and the expected gain from my “new” rebuilt battery?

    I ran 3 “life expectancy” tests, improving my technique and the indicated capacity each time (43%, 48%, 51%, the last with no warnings).

    Another quick exchange with Jack at DrPrius produced this - “Exercise NiMH can get it to rearrange the crystal structure and increase capacity temporarily, however don’t forget the actual capacity decline with each full-cycle, in other words, don’t exercise too much”. BTW, Jack is a true hero. PriusChat should strike a medal for him and the Dr Prius iPhone app.

    Notwithstanding the testing, I was still seeing “Park green, start purple” battery events, and conveniently, the nicely crated battery arrived just when I finished stripping the interior. Then the confusion ramped up again...
     
  3. PriusToadRVer

    PriusToadRVer Junior Member

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    While testing, I read that there’s really little or no difference between “gen 2” and “gen 3” battery modules.

    What’s the complete definition of “gen2” and “gen3” as applied to Prius battery modules?

    Apparently Toyota didn’t publish details of any change or upgrade to them associated with the gen 3 model year. (But I do notice that there are multiple battery parts fitment changes during the gen3 model years?) So, (I guessed) the only practical way to define a “gen3” module is to look at the serial number on each one, which has the manufacture date encoded in it. Note that I originally decided on the “whole battery pack” approach to avoid getting into battery disassembly and per-module balancing work, to get my wife back on the road ASAP. Now I had to do the “QA” function to be sure the rebuild actually contained “gen3” cells. It turns out that each has a QR code on it, so I could scan all and copy to a spreadsheet (all on my trusty iPhone), translate the dates, and compute the age in years.

    The average was 2012, in the middle of the gen3 years, and 27 out of 28 were exactly as expected. Unfortunately, one was clearly anomalous. The date code was actually Sept, 2006, 2 years older than our old battery pack!

    How did a battery made in 2006 stay lively enough to stand tall with the gen3 crowd in 2019?

    And a series-connected battery is only as good as its weakest cell!

    So, does age really have any effect on battery life expectancy? I emailed the battery vendor and called my Toyota dealer tech and management to learn the following:

    “Date doesn’t matter, only a full charge/discharge capacity test and IR measurement matters. That was the best battery we had. Go ahead and install the battery, it’ll last a long time”.

    “Toyota has never published details of battery life and test specifications, but if you had the death triangle, brought it in, reminded us that you’re a 3-new-Toyota customer, we’d comp you a new battery.” (damn, I wish I’d asked that way on my first call!)

    “Our current core value is $1300 and all cores go only to Toyota certified hybrid (recycling?) shops.”

    “If you must know, capacity (AH)>=6.5=“gen3“, and <=5.0 is junk. No per-module or whole battery test data is kept. The paper whole-battery charge-discharge curve is all you get. The one lower-voltage module line visible there is because one voltage sense/compute includes the safety disconnect voltage drop. Please install the battery. It will give you long life”.
    ...
     
  4. PriusToadRVer

    PriusToadRVer Junior Member

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    By this time , my lovely wife seems to be tiring of the noisy, 2-seat weak-battery configuration, so time to shoot the engineer and get on with it.

    With a little help from my grandson, a plywood ramp, and some paracord, we got the swap done with no sparks, scratches, or dents. Reconnect +12 and safety connector for first test, and no joy! Death triangle and P080D means we forgot to push down on the safety lock. Click, done. Then the real troubles started...

    After a couple tries, the best achievable status was grim:

    What is the root cause of death triangle, red !, flashing gas gauge (first one bar, then all bars), VSC, no engine start, and codes cc100 and c3000?


    (Did I mention that the hood had never been opened for any battery work to date?).

    Note that the above codes are not listed in any thread here or any other google I tried.

    Almost all functions except the engine worked normally, including forward and reverse on battery. The engine even started up for a few seconds once, then shut off when we closed the rear hatch!?!?!? And then no more engine.

    Checked the ECU connections twice, reset codes via 12v, OBD, and hold start for 45 seconds. No change. Contacted battery vendor, tried a few more things, then put old battery back in and repeated all the above results identically. So, swapped batteries for the THIRD TIME!

    I’m a complete believer that when things go wrong like this, the beginning of complete disaster is when I expand the work list to as yet untouched parts, but I found a 2008 mk2 fuse diagram, and went thru it to identify all fuses that might affect the engine. When I opened passenger compartment fuse panels, the layouts were not as shown.

    How many different fuse panels did Toyota install on gen2 priuses?

    So, we confirmed that at least one function on each suspect fuse was functional.

    I read one post implying that these codes might implicate the CAN bus, so rechecked the connections on the battery ECU visually and electrically multiple times. OBD bus resistance is correct for 2 parallel terminating resistors.

    At this point, both batteries showed only 1 purple bar, so we started preparing to use the last bit of energy to drive onto the tow dolly and tow it and a bag of cash to a dealer. Meanwhile, we’re getting hungry because my wife has no favorite car to go buy groceries


    So, if you’ve had patience this far,

    What’s the magic bullet to avoid letting a dealer or other hybrid mechanic throw some expensive parts at this brick?
     
  5. bisco

    bisco cookie crumbler

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    nice write up, sorry for your troubles. maybe you need tech stream and the service manual for a better diagnosis.
     
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  6. srellim234

    srellim234 Senior Member

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    Sorry for your troubles, but I can't help but ask: With all of your experience, why did you choose to replace the battery when it hadn't thrown any kind of codes yet? Reconditioning and balancing the existing one seems like it would have been a much safer and more sensible option.
     
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  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Get Mini VCI so that you can retrieve the correct DTC.
    2. <deleted>
     
    #7 Patrick Wong, May 10, 2019
    Last edited: May 11, 2019
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  8. TMR-JWAP

    TMR-JWAP Senior Member

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    How do you triple the cost of a project? Get an engineer involved.

    The only people that disagree with this statement are......engineers.

    Now that I've gotten that out of the way. There's no doubt in my mind that I can help you but there's so much to read...jeezzzzz. I'll throw out some guidance a bit at a time as I read through them...

    One...the car controls the HV battery between ~65% and 42%. Exercising the battery between those two percentages will do nill to increase the capacity of the battery.

    "A gen 2 battery built from Gen 3 cells" is code for getting screwed. Any rebuilder calling them cells isn't knowledgeable enough to be building mud pies, much less an HV battery. A gen 3 module can be anywhere from 2010 through 2015. Gen 2 is 2004 - 2009. Many of these rebuilders are slapping a bunch of early 2010/2011 modules into a Gen 2 case and throwing it out there. Anyone who thinks they're going to get a pack of 2015 modules can just keep dreaming.

    Modules are easy to date code. Every module has a serial number, as you stated. The first two digits are the day of the month. The third digit is the month (0-9, x, y, z) the fourth is the year. L = 2010 M=2011 etc. If I paid for "A gen 2 battery built with Gen 3 modules and it had a 2006 module in it? I'd find a way to pack that battery in their buttocks, just on general principle. I have many Gen 2 modules that still have very high capacities. It all depends on how hard of a life they've had. Toyota and Panasonic did a fine job.

    “Date doesn’t matter, only a full charge/discharge capacity test and IR measurement matters. That was the best battery we had. Go ahead and install the battery, it’ll last a long time”.

    While that may be true, it's not what they advertised, not what they charged you for and not what you paid for. That POS was the best they had? What cheesy-a** place did you get this from? I'd have flipped out on them.

    “Toyota has never published details of battery life and test specifications, but if you had the death triangle, brought it in, reminded us that you’re a 3-new-Toyota customer, we’d comp you a new battery.” (damn, I wish I’d asked that way on my first call!)

    They're blowing smoke. No dealer in America is going to "comp" you a new HV battery because you've purchased 3 new cars from them, even if you do have all your maintenance done there. Especially with no failure codes. 20 new cars, maybe, but I doubt it.

    “If you must know, capacity (AH)>=6.5=“gen3“, and <=5.0 is junk. No per-module or whole battery test data is kept. The paper whole-battery charge-discharge curve is all you get. The one lower-voltage module line visible there is because one voltage sense/compute includes the safety disconnect voltage drop. Please install the battery. It will give you long life”.

    This is the biggest pile of BS I've heard in a long time. Capacity has nothing to do with a module's generation. 2004-2009 Prius=Gen 2. 2010-2015 = Gen 3. Early Gen 2 cars will have 2003 date codes on modules, just like early Gen 3 cars will have 2009 codes. remember model year cars come out in Fall before the actual year. I have plenty of Gen 3 modules that aren't worth their weight in dirt and plenty of Gen 2 modules that are hanging tough.

    Whenever you disconnect the 12v battery, upon re-connecting, place foot on brake, press power button once (many lights will still be lit). Wait a couple seconds and press it again (lights will clear if all is good). The fuel level will default to one flashing pip. It will eventually calibrate itself. It may take 5 minutes or 2 hours. You'll lose radio presets and the auto window up/down feature. Reset the window by raising it and continuing to hold the raise button for about 5 more seconds. The ecu will re-learn the window position and will be good to go.

    Disconnecting the 12v will also cause the car ecu's to lose any adaptive settings they've learned for running the engine. They go back to a default value. If the engine is too far different from default (like throttle body dirty or MAF dirty) the engine will not start. If it sounds like the engine tried to start, it may have just been the HV battery spinning the engine, trying to start it. If it failed to start, guess what....codes and triangle.

    You need a better code reader.

    What do you mean the hood had never been opened for battery work? I'm confused about that. No batteries are under the hood.


    You have either depleted the battery because it tried too many times to start the engine (unsuccessfully) or the car does not recognize that the safety disconnect is installed.

    If you're able to move the car using battery power, then it sounds like that current flowpath is ok, just the engine will not start, See above section about disconnecting the 12v battery and what happens sometimes.

    Measure the voltage between the two main relays in the HV battery (on the battery side) if it is less than 201vdc, it is essentially depleted. If it is 210 or better, it should have plenty of power to crank the engine and should be displaying at least 4 blue bars.

    I'll write more later, I'm exhausted now flipping back and forth between posts, lol.
     
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  9. TMR-JWAP

    TMR-JWAP Senior Member

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    Patrick,

    I believe you're thinking of Gen 1 vs Gen 2/3/4.

    The Gen 1 module is identical in thickness to the other modules, but is just not as long on the body portion. The bottom mounting flange is shorter on the Gen 2/3/4, so the overall length at the bottom is nearly identical and all the mounting holes still line up for all generations. All the terminals are at an identical height. The problem you're thinking of is when someone tries to replace a Gen 1 module with a later Gen. The later Gen terminal will stick out about a 1/4 inch further due to the body being longer. This will prevent the busbar from fitting properly. Actually, it shouldn't fit at all, but some people can break an anvil with a rubber mallet.

    This is why updating a Gen 1 with later Gen modules (except Gen 1.5) requires replacing all 38.

    Gen 1.5 modules (more of a nickname I guess) are OEM replacements manufactured in the same exact Gen 1 style, typically with manufacture dates ranging from 2011 through 2015.

    A 2014 gen 3 module, a 2005 Gen 2 module and a 2011 Gen 1.5 module (exactly identical to 2001-03). I aligned the body portion at the back so it's easy to see the difference in body length.

    IMG_3190.JPG


    The next 2 photos show all three after the bottom flanges were aligned. Notice the terminals are all identical. The gen 1 body is slightly shorter, but the bottom mounting flange is almost identical in length.
    IMG_3192.JPG IMG_3193.JPG
     
    #9 TMR-JWAP, May 10, 2019
    Last edited: May 10, 2019
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  10. exstudent

    exstudent Senior Member

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    How much was that "Gen3 rebuild" you purchased?

    100% new OEM, HV Battery could be had for $1599 (Nov 2018); read post #9 & #11.
    Life would have been simplier/easier, going NEW OEM, and possibly cheaper, than your "DIY Pre-emptive HV Battery replacement."
     
  11. PriusToadRVer

    PriusToadRVer Junior Member

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    ...

    Since it took a while to write all this, spoiler alert - we got it running for under a buck!

    I went back thru the fuse diagrams and located a few evasive fuses to check further. The first one I put a multimeter on had a 14 volt drop! Yes, it was the AM2/IGN 15A fuse under the hood, and yes, it came up ready. A short 12V disconnect, and NO CODES!

    So,

    1. How did swapping a battery take out the AM2 fuse, or what caused it to blow?
    2. Why can’t the ECU gurus do better than a couple undefined codes? If I’d have been on the interstate when it blew, it would have been costly and unsafe.
    3. Why doesn’t Toyota provide owners with better tech data?
    We put ducts n vents back in, drove it around for a while, and it was easy to see that the new battery is stronger.

    Cleaned and Reassembled a few dozen interior parts, then did the final test - Dr. Prius life expectancy test ( remember old battery at 40-50%, near end of life). The test took about 30% longer to complete, and I almost froze from keeping the discharge rate in the green with the A/C, and life rating 125%compared to a new battery. So, yes, Virginia, there really is a “gen3” battery improvement available! Thank you Mark at Falcon Hybrids.
    BTW, the posters here and some other threads (some pretty senior members, I notice) are way more hostile to both “gen3” and Falcon than my very diligent experience would support. I thought a moderated forum would produce better information. If I’d read that hostile stuff, I’d probably have chosen (unwisely, in retrospect) to equip and fuss with module level repair and rebalancing.
    We should reserve our hostility for the Ovshinsky/GM/Texaco/Chevron (and yes, in this restricted context Japan/Panasonic/Toyota, and USPTO) conspiracy that deprived us of this valuable technology for decades and left us with a proprietary, secretive, restricted parts market.

    With only a little luck, I’ll probably get much more than the warrantied one year life.

    But, now I have to wrestle with that AM2 fuse mystery, and hopefully respond to some of the above helpful posts...
     
  12. PriusToadRVer

    PriusToadRVer Junior Member

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    1. I had 3 price steps - “gen 2”, “gen 3”, and dealer new. Each about $400 apart, with due attention to core and shipping costs.
    2. There has been some risk expressed that “new” may have some issues (old module dates, balance, and, of course actual capacity.
    3. Age is much less a factor than tested capacity, and average/peak temps during storage or prior use are also a factor.

    So I chose the middle step. In retrospect, new would not have helped me at all, but only the next hopefully 4-5 years will close the case.
     
  13. PriusToadRVer

    PriusToadRVer Junior Member

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    This complexity is one reason I wanted to avoid module-level fun and games.
     
  14. PriusToadRVer

    PriusToadRVer Junior Member

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    Cause I tend to be at large in America all summer, a long ways away from my garage, and potentially a long ways from either HFT or Toyota level civilization.
     
  15. PriusToadRVer

    PriusToadRVer Junior Member

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    Bought one. It seemed so unfriendly to my iPhone that I decided further oldfart diagnosis (voltmeter on fuses) would be more fun. In retrospect, not sure it would have done better, but I would like to read a system analysis on this...
     
  16. TMR-JWAP

    TMR-JWAP Senior Member

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    Very glad to hear you got the car going again. Not sure what you were looking at, but it could not have been the AM2 fuse. When the AM2 fuse opens, you pretty much lose the entire dashboard display. AM2 most often opens when the inverter cooling pump fails (shorted windings or pump seizure)
     
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  17. SFO

    SFO Senior Member

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    The mini-vci cable is generally used with a winblows laptop. Some have used it with a Macbook or similar, and an emulator like Virtualbox.
     
  18. Skibob

    Skibob Senior Member

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    When I read this I was thinking something completely different. The statement that stood out to me was you were having difficulty starting the ICE before the battery change. The engine compensates for changes in the sensors but when you disconnect the battery they go back to default settings. I was thinking you would have to clean the mass airflow sensor, clean the throttle body and change the plugs.
     
  19. PriusToadRVer

    PriusToadRVer Junior Member

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    Sorry if I wrote imprecisely. When I started the “project”, the only solid problem was park-green-start-purple, and occasional hesitant acceleration because low hv battery soc. I did have to charge the 12v for a few hours only once, and thorough testing later indicated battery ok. All the ICE crap came up (apparently purely by coincidence) during the first battery swap. I had a long talk with a senior toyota tech, and he couldn’t offer any better strategy on the am2 fuse than “drive it til it blows again”. I’ll probably add occasional “touch the fuse after a drive” tests, and if I burn my finger, I’ll dig into the inverter pump. It does seem to be running better ( fuel economy) day by day, presumably as it relearns detail parameters after all the resets.
     
  20. PriusToadRVer

    PriusToadRVer Junior Member

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    Here’s the fuse document...
    upload_2019-5-14_9-11-45.png
    Note number 31...
    Here’s the dash...
    upload_2019-5-14_9-17-16.jpeg
     
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