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How to turn off alarm after changing 12V battery?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Katya S, Feb 15, 2018.

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  1. Katya S

    Katya S Junior Member

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    I looked everywhere but couldn't find my exact problem maybe anyone here can help out.

    A few days ago I woke up to my Prius nonresponsive, so we assumed the issue is the Aux Battery, so my uncle bought one and replaced it (he's not a mechanic but he has done it successfully on a gen 3 Prius before and this problem didn't arise).

    To open the back in had to squeeze in from the front and use the trunk latch, and we have pretty much finished the replacement sans a few decorative screws.

    But when he connected it to the -, the lights and alarms went OFF which was not good in a subdivision at night.

    How do I stop it? I tried inserting the plastic key thing in and out and click the buttons on it(it is charged because the little light on it goes off), but that didn't really contribute much.

    Any help? Thank you.
     
    #1 Katya S, Feb 15, 2018
  2. Stevewoods

    Stevewoods Senior Member

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    So, to try to take this logically, what has changed?

    You put in a new battery.

    I know you have a new battery, but I might suspect it has some issue that might be causing a voltage fluctuation.

    Just cause something is new, doesn't mean it might not be good.

    Number two, just a quick google on this forum shows that someone suggested pulling the dome light fuse for a few minutes, apparently it has something to do with the alarm power.

    It is in post #6 in this thread:

    Reset alarm after battery boost? | PriusChat
     
    #2 Stevewoods, Feb 15, 2018
  3. Katya S

    Katya S Junior Member

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    Not really an update since I haven't tried anything yet, but I just realized that the week before that the car would flash the door open signal light whenever I started driving from a streetlight, I didn't even realize it at first since the light would light up for a fraction of a second. Could this be related somehow???
     
    #3 Katya S, Feb 15, 2018
  4. bisco

    bisco cookie crumbler

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    perhaps a door switch is not contacting properly, and drained your 12v. usually, it's the hatch.

    is it an aftermarket alarm?
     
    #4 bisco, Feb 15, 2018
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  5. Katya S

    Katya S Junior Member

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    I will look into the origin of the alarm later today. Are all doors and the trunk supposed to be closed after I reconnect the battery? I'm afraid I'll just lock myself out and have to spend a good 2 minutes getting back into the car to open its trunk and disconnect the battery to stop it yelling ;(
     
    #5 Katya S, Feb 16, 2018
  6. Prodigyplace

    Prodigyplace 2025 Camry XLE FWD

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    The instructions should be documented in the manual for the alarm system. I am not aware of any Prius alarm system supplied by Toyota but some dealers install aftermarket ones.
     
    #6 Prodigyplace, Feb 16, 2018
  7. Katya S

    Katya S Junior Member

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    I will try the procedures for deactivating the theft alarm soon (at an earlier hour maybe haha). I hope me forcing the back open with the latch won't be a problem :S

    Thanks to everyone for help and I'll update the thread with what fixed it for me (if it does).
     
    #7 Katya S, Feb 16, 2018
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  8. Prodigyplace

    Prodigyplace 2025 Camry XLE FWD

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    If you know what dealer originally sold the car, they should know the procedure too.
     
    #8 Prodigyplace, Feb 16, 2018
  9. bisco

    bisco cookie crumbler

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    i would first check the 12v health. once you know it's good, you can close and lock everything with confidence.
    fiddle with the hatch closing while someone sits in the drivers seat watching for the light.
     
    #9 bisco, Feb 16, 2018
  10. RobH

    RobH Senior Member

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    Press lock/unlock on the keyfob several times. That worked on a 2008 with the factory alarm.
     
    #10 RobH, Feb 16, 2018
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  11. SFO

    SFO Senior Member

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    Linked, if you can't locate the manual : 2005 Toyota Prius Owners Manual and Warranty - Toyota Owners
     
    #11 SFO, Feb 16, 2018
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  12. Stevewoods

    Stevewoods Senior Member

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    As mentioned by others, sounds to me like a door/hatch contact issue.
     
    #12 Stevewoods, Feb 17, 2018
  13. Prodigyplace

    Prodigyplace 2025 Camry XLE FWD

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    Delete
     
    #13 Prodigyplace, Feb 18, 2018
  14. Katya S

    Katya S Junior Member

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    The lesson of today is read the manual, it was the theft deterrent system and was turned off rather easily by unlocking the car with the key. Thank you so much everyone who helped, you guys are the best :)
     
    #14 Katya S, Feb 18, 2018
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  15. Farsan

    Farsan New Member

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    Hi Katya, I am having the same issue as you. You mentioned previously that inserting the plastic key and clicking the unlock button did not work. Could you please clarify how you managed to fix it?
     
    #15 Farsan, Dec 16, 2020
  16. sub3marathonman

    sub3marathonman Active Member

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    And, even over six years later, your helpful update solved the problem for me. I thought putting the FOB in the ignition would stop it, but no, but the little key unlocking the door did it.
     
    #16 sub3marathonman, Mar 10, 2024
  17. ChapmanF

    ChapmanF Senior Member

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    Yeah, the alarm was unconscious while the battery was dead. The last thing it knew, the car was all locked up and armed, and now it wakes up and sees a door or hatch open, and it never saw you use the key or fob to unlock it.

    When it has happened to me, I've also been able to silence it just by pushing the unlock button on the fob. Not sure why that wasn't working upthread.
     
    #17 ChapmanF, Mar 10, 2024
  18. dolj

    dolj Senior Member

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    #18 dolj, Mar 10, 2024
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