Theft-deterrent indicator flashes, nothing else works

Discussion in 'Gen 3 Prius Main Forum' started by Mr. F, Sep 23, 2020.

  1. Mr. F

    Mr. F New Member

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    The vehicle doesn't seem to be responding to the fobs. I can still get inside using the metal key, and this is what I see:
    1. flashing theft-deterrent indicator
    2. doors open indicator when the front door is open
    3. hood release button releases the hood only partially (about 1.5"), preventing access to the 12V battery
    4. pressing down on the brake pedal turns the POWER button LED from red to green
    5. holding up the fob (Toyota logo) to the POWER button doesn't do anything
    I checked and the fob battery is at 3V. The car was purchased from a dealer on Monday, and I haven't had any issues driving around the last two days. What could be going wrong? Is any of the behaviors unexpected?
     
  2. Grit

    Grit Senior Member

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    Check your 12v battery health.
     
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  3. bettergolf

    bettergolf Active Member

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    What Grit said, and, oh yeah, it's not under the hood as indicated in your line #3.
     
  4. Grit

    Grit Senior Member

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    :whistle:
     
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  5. Johnny Cakes

    Johnny Cakes Senior Member

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    What is the "nothing else" that "doesn't work?"

    2. doors open indicator when the front door is open
    If the front door is open, then door open indicator is normal

    3. hood release button releases the hood only partially (about 1.5"),
    That's all the hood release button does. There's a second latch under the hood.

    4. pressing down on the brake pedal turns the POWER button LED from red to green
    That's good.

    5. holding up the fob (Toyota logo) to the POWER button doesn't do anything
    What did you want it to do?

    Do the headlights work and seem bright?
    What happens when you press the POWER button while your foot is pressing the brake?
    Did you leave anything on or doors open for a long time?
    Have you tried jumping it? There is a jump connector under the hood which is the easiest location. The actual battery is in the back.
     
  6. Mr. F

    Mr. F New Member

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    I should have mentioned that it's the hood catch that's giving me trouble—the release lever is fine. I've opened the hood a few times before and it's been okay. I'll try again in the morning when I can see clearly.
    Thank you all for your advice! Everything does point to the 12V being drained, and I was definitely mistaken about its location.
     
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  7. fuzzy1

    fuzzy1 Senior Member

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    1. With foot still on brake, then holding fob to the Power button, then you also have to press the Power button too.
     
  8. Mr. F

    Mr. F New Member

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    I did manage to get the hood up so I cleaned and lubricated the release mechanism while I was at it.
    The 12 V battery is at 3.1 V. I'm going to attempt jump starting it tomorrow.
     
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  9. bisco

    bisco cookie crumbler

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    new battery needed
     
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  10. Mr. F

    Mr. F New Member

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    I can definitely do that. How did you figure out a replacement was needed?
     
  11. Grit

    Grit Senior Member

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    Bisco is the prius whisperer.

     
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  12. jerrymildred

    jerrymildred Senior Member

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    Make quadruple sure you have the polarity right. If you mix it up you might get lucky and only have to replace a few fuses. More likely, you'll destroy some expensive stuff. Lots of sob stories about that here.

    It's not for sure, but running the battery down that low will greatly reduce it's lifespan. If it's already old, that could be the death blow.

    I have a lithium battery pack in case I need a jump. So far I've used it twice; both times on other people's cars. I also have a regular charger and a Battery Tender Jr. that I use very very rarely, but when you need it you need it. Recommended equipment for all car owners.

    On the jumper cables, I no longer own any and will not use them on a Prius unless it's ABSOLUTELY necessary. The boost pack doesn't cost much more and it checks polarity before energizing the clamps.
     
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  13. bisco

    bisco cookie crumbler

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    you can't recharge a battery from 3.1 volts, how old is it?
     
  14. Grit

    Grit Senior Member

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    The other stuff that’s not working?
     
  15. Mr. F

    Mr. F New Member

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    That's exactly what I was planning to use. It should be arriving in the mail today.
    I'll have to check. On a side note, I do remember that the voltage was about 11.9 V when I ran a health check via Techstream just before the trouble started. I probably ran the battery down with the car out in the heat and with the fan and onboard computer running for close to 2 hours.
     
  16. jerrymildred

    jerrymildred Senior Member

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    I think you can charge it with a dumb charger. A smart one will either not try or will assume it's a 6V battery. Either way, it's likely to be toast.
     
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  17. Johnny Cakes

    Johnny Cakes Senior Member

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    Plan B with smart chargers is to add a good battery in parallel until the overall voltage is at a point where the smart charger will recognize it on its own.

    But I agree -- I don't think you recover from 3v or if you do, you have a compromised battery.
     
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  18. Mr. F

    Mr. F New Member

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    I'll try charging it with the NOCO Genius 5, which looks like it will be able to act as a dumb charger if necessary. I should also be able to force it to recognize the target battery as a 12 V AGM.

    I'm going to take everybody's advice and replace it. For future reference though, at what voltage level (or other conditions), if any, would I need a jump start but still be able to keep the same battery?
     
  19. Mr. F

    Mr. F New Member

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    I had initially measured the voltage at the recommended jumper cable locations—the voltage at the battery terminals was 4.77 V. I was able to recharge it using the NOCO (it did take nearly 16 hours to finish).
    I'm still getting 50 mpg if I drive carefully, so I think I may be able to get by with the same battery for now. No corrosion on the terminals, no date cutouts on the sticker.
     
  20. bisco

    bisco cookie crumbler

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    that is deadly low, all the best(y)
     
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