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HV Battery? or Coolant?

Discussion in 'Gen 2 Prius Main Forum' started by schmitty, Feb 9, 2019.

  1. schmitty

    schmitty New Member

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    I could use some help. Thanks in advance.
    2007 Prius. +225K miles

    On a frigid morning during the cold blast last week (I live in western Mass), I started my 07 Prius and various lights went off:
    VSC
    The yellow brake light
    Check Engine Light
    The Master Warning Light
    After some driving that day, a fan adjacent to the rear passenger seat started running nonstop. I believe this is the HV battery fan. I popped in my cheap diagnostic reader and no codes came up. I thought maybe it was the cold and gave it some time. Nothing changed. After some research, I was directed to the 12V battery. Had my local NAPPA parts store check it and it was working perfectly. After some more head scratching, I decided to take it to Toyota and pay their diagnostics fee. They immediately came back with the news I was expecting: the HV Battery is failing.

    One thing that might be worth considering: I recently changed out the coolant pump after getting a check engine light and error messages for that. It was my most advanced auto repair to date. The pump went in easily, however I'm not completely sure I bled out the coolant line properly. This was probably 2-3 months ago. I only mention it because in doing some research, that came up as a troubleshoot. The car has been running fine otherwise with no gurgling noises or anything else noticeable.

    I guess some of my questions are, could the problem be the coolant line? Would it be worth it to try to bled out the system again? Or have a shop do it? If it truly is the HV Battery, is it recommended to change out the whole thing or change out the individual blocks that are failing?

    Many thanks in advance.
     
  2. bisco

    bisco cookie crumbler

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    welcome!
    if you are going to diy, get a copy of toyota tech stream diagnostic software.

    you should be able to find proper coolant bleeding technique videos on line, or threads here.

    if not, subscribe to the service manual at tech info.toyota.com

    i would check the 12v myself with a volt meter, how old is it?

    if it is indeed the hybrid battery, start by pulling it and cleaning all the corrosion. if that doesn't work, use tech stream to find the bad cells. you can learn how to replace and rebalance, but it is still a temporary solution.

    if you want to keep the car long term, you can get a new battery for $1,600.

    it may not be too late to recondition the whole battery as is, in the car, with prolong recondioner. idk
     
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  3. jerrymildred

    jerrymildred Senior Member

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    We've learned the hard way that rebuilding batteries rarely ends happily. Unless you are super meticulous in matching cells and then use the Prolong grid charger, it will fail again in a few months or maybe sooner. Even perfectly done, you still have an old battery.

    New battery prices have really dropped in the past year or so. Toyota should have given you the specific diagnostic codes when they read them. That's what you paid them for. That check engine light is a little curious. I don't think that's typical with a failed traction battery so you might have an additional problem which may or may not be in the engine cooling system.
     
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  4. schmitty

    schmitty New Member

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    Thank you both for your time!

    I'm still researching Toyota Techstream software for Mac. Is there a thread here in Prius Chat? I can't seem to find one. Hopefully some more research will prove beneficial.

    Regarding the coolant: I watched and followed proper techniques both here on PriusChat and YouTube. I rechecked this morning, by putting the car in IG-ON and listening to the pump. A method described by Patrick Wong here: 07 prius check engine light. need to bleed the air in the coolant? | PriusChat After doing this, all seemed fine. So at this point, I'm not convinced it's the coolant lines.

    I'm almost positive the 12V is original to the car. I'll get out the voltmeter and check later today, but I did try checking it through the MFD. With the car in ACC and getting to the Vehicle Signal Check Mode on the MFD, the battery dropped to 11.5V after probably 60seconds. If I left it on longer, it might have dropped lower. Then leaving the Vehicle Signal Check Mode on the MFD I turned the car on and the volts quickly jumped to 14.0V and stayed pretty constant. It seems close to normal, but that might be low...?

    And yeah, I figured rebuilding the HV battery was beyond me, but I thought I had it in me to swap out a new or refurbished one.

    I can't seem to find the print out from Toyota. As soon as I get my hands on it, I'll post them here.

    Thank you.
     
  5. jerrymildred

    jerrymildred Senior Member

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    No such thing, which stinks. I'm a Mac user, too. TS only runs on Windows. And the version of TS you get from Amazon or Ebay with the OBDII adapter is an old, not-quite-legal one. Those drivers are 32-bit drivers, so you need to really jump through some hoops to get them to run on new versions of Windows. There are multiple threads here that can help you install it.

    I have an old Linux laptop. I installed Virtual Box ( Oracle VM VirtualBox ) on it and then put my ancient copy of XP within Virtual Box. I keep the wifi off so hackers can't get in. It works perfectly. Virtual Box is free and open source, and they have a Mac version, so all you'd need is a 32-bit version of XP or Win7.

    11.5 does seem low depending on what stuff is turned on. 14V in ready mode is about right. That just tells you that the charging system is working. I usually see a whisker over 14V, so that could be an indication that your 12V is low. I prefer to check the 12V battery with a multimeter.
     
  6. dolj

    dolj Senior Member

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    You can do the same on a Mac using BootCamp, too which is also free. In addition you can setup a Windows VM in VMWare Fusion or Parallels (not free) but it works well.
     
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  7. jerrymildred

    jerrymildred Senior Member

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    I ran Windows using Parallels on my office Mac for a while until I was able to completely sever ties with M$.
     
  8. ericbecky

    ericbecky Hybrid Battery Hero

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    Get a way to see live data via tech stream or with a cheap $20 Elm327 Bluetooth OBDII adaptor and a $6 phone app. Perhaps one of the modules is bad and you could see it that way just to confirm.

    Too bad the dealer didn't provide a bit more info.
     
  9. schmitty

    schmitty New Member

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    OK!

    Thank you all for the techstream options. I will explore them soon enough.

    Update:
    Batter tested with voltmeter: 11.9V when the car is off. 13.9V with the car running.
    Dealer codes reported: POA80

    At this point, I'm more than likely to swap out the HV battery. Thankfully, there are loads of options out there. And yeah, I was hoping on more from the dealer. That's why I went there.
    The 12V seems a little low. I should probably swap that out too?

    Thanks again for the support. It was very helpful in working things out.
     
  10. bisco

    bisco cookie crumbler

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    you could try charging the 12v, how old is it?
     
  11. schmitty

    schmitty New Member

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    I'm pretty sure it's original to the car. '07.
     
  12. bisco

    bisco cookie crumbler

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    that would be amazing, and well worth a new one.
     
  13. schmitty

    schmitty New Member

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    I don't think I can let it go... might be the linchpin holding the whole car together!
    Much gratitude for this forum and community.