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Prius won’t start: 12v battery or something else?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by SuperGLS, Jul 10, 2020.

  1. SuperGLS

    SuperGLS Member

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    Tried to start my car today and this kind of thing happened. At first I thought everything was ok and tried to shift from P and it wouldn’t let me. Then I noticed the dash going crazy. First most of the dash lights up and flickers, then only part of it flickers, then at the end only the triangle with exclamation point of the left side flashes.

    I looked through some other threads and thought maybe it’s the 12v battery (hasn’t been replaced, just shy of 90K miles). But would the key fob still open the doors and would the dash act like this if the 12v was dead?

    Should I try to jump it and see what happens?

    Sorry for the poor quality video, it’s sunny outside.



    Any ideas? Thanks in advance!
     
  2. ttou68

    ttou68 Active Member

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    It is possible, but you should have the 12V checked..
    Also, did you shut down the vehicle after you tried to start it or dash turned off on it's own?

    Posted via the PriusChat mobile app.
     
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  3. SuperGLS

    SuperGLS Member

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    The triangle icon kept flashing but since nothing else was happening I hit the Power button a few times to get it to change from red to off (no light on).

    Honestly it’s probably less hassle for me to go buy another battery and swap it out rather than get it checked by the dealer. But if there’s a known problem that causes this, besides the battery, then that’s probably the right idea.
     
  4. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    If your 12V battery is below 12V especially by much, it can't power up all the various computers and you'll get a lots of weird effects. Check the battery first. I wouldn't just go buy one without checking. This happened to me on my 2010.

    Too much outside light pollution to see what's happening on your video.
     
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  5. SuperGLS

    SuperGLS Member

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    This is probably a dumb question, but I guess I need a multimeter to check it, right? I visually looked at it and it looks fine, there is no corrosion.

    A neighbor wanted to see if he could help and we tried to start the car again and this time only the triangle with ! icon was flashing. I popped the hood to show him the place we could jump it and near the fuse box there’s a constant humming/buzzing noise.
     
  6. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    Just looking at it will not do. It needs to at least have it's voltage checked with a multi meter or tester.

    Depending on the chart you look at:
    12.6 V = 100%
    12.06V = 50%
    11.9V = 40% (not great but usually works OK)
    Trouble zone here and below.
    Depending on age may be able to recover with charger but replacement is a higher probability at this level and below.
     
    #6 Mark57, Jul 10, 2020
    Last edited: Jul 10, 2020
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  7. SuperGLS

    SuperGLS Member

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    Thanks Mark. I guess I will try to jump it in the morning and if that works take it too Autozone for them to check it.
     
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  8. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    Sounds like a plan. If anyone close has a smart charger it might bring it up enough to get it checked out at Autozone tomorrow . Some smart chargers will tell you the voltage and do a test.

    All your symptoms sound exactly like what my 2010 did when its 12V died.
     
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  9. ttou68

    ttou68 Active Member

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    I wonder if there's a short in inverter pump?

    Find the 15A AM2 fuse (located on Unit B in the main relay/fuse box), and check if it has blown. If that is good, find the INV W/P relay which is in the vicinity of the fuse box located behind the instrument panel, driver's side.

    Also, are you able to pin point location of buzzing sound?



    Posted via the PriusChat mobile app.
     
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  10. SuperGLS

    SuperGLS Member

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    The AM2 fuse is listed as 7.5A in both the manual and fuse box cover. I checked that one and it was ok. Unfortunately the car is parked on a somewhat busy city street and I can’t access the other fuse box without having my feet out in the street...

    The buzzing sound seems to be coming from this piece with the X1 sticker on it (which is directly to the left of the fuse box). It went away shortly after opening the hood (this being an hour or more since I last attempted to turn on the car).
     

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  11. ChapmanF

    ChapmanF Senior Member

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    There's a little pump tucked away near that piece ... probably the sound you were hearing.
     
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  12. SuperGLS

    SuperGLS Member

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    Update: getting a jump worked. Drove to autozone where the unhelpful employee said they don’t check 12v batteries in hybrid vehicles and wouldn’t install a new battery either. I just bought the new battery, drove home, installed it and took the old one back.

    The car seems to be running fine so hopefully that’s it. I’m actually due for my 90K service anyway so I’ll see if the dealer will uncover any other potential problems.

    Thanks for the help everyone!
     
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  13. bisco

    bisco cookie crumbler

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    congrats! get a maintainer if you're not driving much
     
  14. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    What an idiot. It's just a 12V battery. Be sure to leave them a detailed review. Glad it worked out. If you're not driving as much due to Covid-19, be sure to either drive it about an hour a week or get a battery maintainer or charger to put on it every 9-10 days. Hybrids "do" things in the background even when they are not on and it tends to drain the 12V battery over time if it's not being driven much. Good luck.
     
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  15. SuperGLS

    SuperGLS Member

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    I’ve been driving only a little less that normal as I’ve still been going to work at least 3 days a week this whole time. But it was still the original battery so that’s probably what did it. Hopefully the car will start tomorrow when I give it a try.

    The Autozone guy did give me 10% off the entire transaction for no reason (at least no reason that I could tell), so it wasn’t all bad I guess.

    edit: I just realized I posted this in the wrong forum (should have been in the gen 3 forum).
     
    #15 SuperGLS, Jul 11, 2020
    Last edited: Jul 11, 2020
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  16. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    I think you're right. I was able to get 6 years out of my original 2010 Prius battery which was phenomenal.
     
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  17. kenoarto

    kenoarto Senior Member

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    Was this the original 8 year old battery?
    Posted via the PriusChat mobile app.
     
  18. SB6

    SB6 Member

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    I've had auto part stores refuse to check things for me when they realized the car is a hybrid. I guess they just don't know much about hybrids, and therefore get intimidated and are afraid they will damage something. If you ever need to get your battery checked again, try physically taking the battery in
     
    #18 SB6, Jul 14, 2020
    Last edited: Jul 14, 2020
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  19. MikeDee

    MikeDee Senior Member

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    I had the dealer check my battery when I had it in for service. They said it was still good, but weak. I'm not sure how they tested it. I bought a new one from the parts department and installed it myself. They wanted too much to install it. The battery was 7 years old. It was due for replacement anyway.