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Hybrid and 12v Battery Issues

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Ewen505, Mar 30, 2019.

  1. Ewen505

    Ewen505 New Member

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    Hello all!

    I'm a longtime reader, but this is my first post. This site has been invaluable as our 2007 Gen 2 has climbed in age and I've started doing some of my own repairs - which, thanks to this awesome car, have been really minimal until now. I'm a younger hobbiest, I've worked on cars with my dad since I was little, and in the last couple of years my own cars have started aging and I've done all my own work as they each climbed over 150k miles.

    The 2007 is now almost to 215k, so I'm pretty happy with the life we've gotten. A couple of days ago, my wife went to go to work and got the Christmas tree of warning signals. I had her hop into our other car and I grabbed my OBD II scanner. Pulled P0A80 and (somewhat) oddly a P0130 code.

    I figured the hybrid battery was done, and given the miles, we've begun preparing to move on to a used Gen 3.

    However, I thought since the P0130 was there too, maybe, just maybe the 12 volt was bad and if we're lucky that's the (sole??) cause of our issues. I know not likely with the P0A80, but still... We've had the car since 2014 and never replaced the 12 volt, even with it dying on us once or twice due to left on dome lights, etc. and I know when they're getting toasted they can throw weird codes.

    I did the onboard 12 volt test and the numbers were floating between 9.9-10.1v, and dropped if I turned on the headlights, etc. So, definitely suspect the 12 volt is weak/dying. I decided to get Torque Pro and see if I could verify anything about the HV blocks. (I use an iPhone these days, so had to find and charge an old android, buy the app, customize the PIDs, etc). All of about 45 minutes passed from the onboard 12 volt test to going back out there.

    Took my OBD II reader out to the Prius, plugged it in, opened Torque Pro, turned on the car - and now it won't even boot enough to get the computer started. No screen, and no data running through the OBD II reader. Sometimes I get as far as the warning dash lights all coming back on, but no ICE movement.

    SO! Questions:

    Can I use a non-prius 12 volt just to try and get things started to use Torque Pro and check the hybrid blocks?

    I wouldn't 'install' the other battery, just wondering if I can pull it out of my Subaru, hook up to it, and see if that gives it the juice to at least get the computer up and running again... or is this a terrible idea given the Prius' unique relationship to 12v?

    Otherwise maybe I'll run the 12v to Autozone and have them charge it up and see if that can get me enough life to run Torque?

    Based on the P0A80 code and symptoms, am I for sure looking at a new HV battery situation?

    Just wondering if folks have thoughts about how far down the rabbit hole of worrying about the 12 volt I should go, vs. just saying the P0A80 is almost certainly pointing towards the hybrid battery as the real problem here.

    Other quick notes:
    The only repairs it's needed in the last 30k or so have been:
    1) A replacement 3 way coolant valve. Check Engine popped on, checked the code, did the research, swapped the part, everything was fine.

    2) More recently though, (probably about 2k miles or so ago?) my wife was driving and got red triangle of death and it was the inverter coolant pump. She was on a highway, so had to drive on it for a couple of minutes to get to an exit. I met her, got the part, swapped that and everything went back to normal, pump worked, etc. - but I know the code only trips after the inverter has already overheated. I mention it because I figure this could be something that in turn puts a weak HV battery in further jeopardy?

    Thank you for any insights!
     
  2. bisco

    bisco cookie crumbler

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    welcome!

    1) yes. check the codes after the good 12v is installed and report back.
     
  3. Ewen505

    Ewen505 New Member

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    Thanks! Alright, here's the update:

    The 12v was definitely on its way out - maybe because the Hybrid was too. But between writing the original post and going back to the car I got locked out and had to use the manual key to get in and access the 12v again o_O

    Yanked and trickle charged the 12v overnight at AutoZone, popped it back in and everything worked normally, ICE was back on, codes and dash were clear, etc. (but I know that can be from the battery re-set, so wasn't using that as a reference). I ran Torque Pro while sitting there and the hybrid blocks all looked pretty good - so I was optimistic it was just the 12v all along. I knew I needed to test it under driving loads though, and didn't want to test it with the 12v auxiliary that I knew to be bad.

    So, picked up the Bosch 12v from PepBoys since it's the cheapest option here (and has the best warranty). Installed it, everything looked great - Fired up Torque Pro, took it for a drive and... started noticing Block 4 can't hold the charge. Made it about a mile and the ICE started kicking on and off at stops - a few minutes later, all the warning lights popped back on. In hindsight, kinda wishing I'd saved $150 and just tried driving a bit on the re-charged original auxiliary battery - but I was afraid I would never be confident in any results with that one in there. I'll see if Pep Boys takes mercy and accepts a return for a battery that was used literally once.

    Back to shopping for a new Prius! We're thinking Gen 3 with relatively low miles. (Open to opinions on year, or if we should be looking at others such as a Prius C??).

    At 215k, as second owners who really used the heck out of this car, it's tough to let it go. But given the price of a new HV, I feel like she's done us good and we need to move on.
     
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  4. Stevewoods

    Stevewoods Senior Member

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    Not smart enough to offer any words of wisdom, just my best wishes!
     
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  5. Salvage09

    Salvage09 Junior Member

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    When the 12v battery voltage is low, you can get all sorts of weird error codes AND all sorts of weird malfunctions that eventually go away when you replace it with a new AGM battery. Was the Bosch an AGM specifically for a Prius? I'm not an expert, but if it's a regular 12v battery, it may not act the same, different charging curve, etc. They usually cost $175-++
    The Optimus Yellow top is probably the best mass market replacement.

    10v is definitely low.

    The traction battery is replaceable, and there are guys here in LA who rebuild them for ~$1200 IIRC. Where can you get a 2007 Prius for $1200?

    I also found the OBD interface is the easiest way to get the voltage.
    I have a 2009 bought from salvage, now ~150k, still going strong, probably needs another 12v battery soon.
    BTW, DON'T trust the dealership or mechanics because you're just as likely to find the answers here on PC!

    I had a dead inverter coolant pump, TOLD the dealer, they refused to believe it was anything but the 12v battery, which was a new Optimus yellow top. AVOID Bakersfield Toyota in town-service writer is an idiot. The other branch might be ok but $$$$.

    Best wishes!!


     
  6. Salvage09

    Salvage09 Junior Member

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    Just checked voltage on 6 yo 12 v battery
    Off, at Jump terminal 12.68
    using Scanmaster lite OBD one push 12.2
    using Scanmaster lite OBD two push lights on 11.9
    using Scanmaster lite OBD Ready mode: 14
     
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  7. Ewen505

    Ewen505 New Member

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    Ah! You're pulling at my heartstrings!

    Indeed, the Bosch is a new AGM specifically for the Prius. Read about it here on PC, favorable opinions all around it seems. Looked it up and was pleased to find it was at Pep Boys, way cheaper and had a better warranty than the Optimus or OEM replacement. Good thing too, because Pep Boys (and others) won't accept a return on the battery once it's been hooked to vehicle terminals, so I do have I solid Prius battery even if I don't have a good car to put it in just now (it also works in a Gen III, so...).

    Anyhow, once that 12v was in and I drove a bit, it was super clear it's the HV battery. I could watch the cell blocks in Torque Pro and my Block 4 would literally jump up to 17volts with the ICE on, the ICE would shut off as I slowed or stopped, Block 4 would dip down to like 14 volts while everything else held the same numbers (in the 16-17v range). ICE would kick on for a few seconds, Block 4 would jump back up, ICE would shut off, Block 4 would dip, ICE back on, etc, etc...

    It only took 3-4 cycles of that happening before all the dash lights popped back on and it re-threw the P0A80.

    As for reviving the HV... if the timing wasn't such that it also needs new tires, brakes, and just got a nasty new crack in the windshield I might say getting a new Hybrid Battery would be worth it. But at 215k, with all those needs and some other general maintenance needs just around the corner, I think I would live in fear of justifying the decision with each new need/repair. I've also been reading through the forums and think if I did the HV I would just get it new from Toyota (I found it for about $1800) rather than reconditioned, and really try to take the car the distance. Much as I'd love to just go for it, we're not in a financial place to take it on as a project car which is what I fear it would become.

    That said, we haven't fully decided to give up. We're just shopping for a used Gen III with decently low miles so that we have something we know we can count on. Our 2nd car, a Subaru - is also old and high miles, and being in SoCal, the miles rack up quickly. For now I'm hoping we can park the Gen II while we find a good Gen III, then I'll see what the future holds for it.
     
  8. bisco

    bisco cookie crumbler

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    iirc, 2014 gets new rings, and 2015 gets new pistons. afaik, they still have the egr problem though
     
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