Sticky Thread on Gen 2 Prius Alarm Fix?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by JP GEN 2 Prius, Dec 18, 2018.

  1. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    Writing this thread at 2AM due to having the Prius wake me and neighbors up. I have a 2005 Toyota Prius which the alarm tends to go off quite frequently at 2am-3am in the morning has been happening around once a week. This seems to be incredibly common issue when using the search function yet I see know definitive answer on what causes the issue. My goal is to determine what that issue is and have a sticky thread so anyone in my shoes doesn’t make enemies with their neighbors.

    Facts:
    -New 12V Battery
    -I have Techstream software and option to disable horn from alarm seems to be non existent possible pointing to the dealer installed alarm I’ve read about?
    -If is Toyota dealer alarm, I cannot find the sensitivity adjustment under the dash that I have seen in Tacoma threads
    -Car kept outside, which their may potentially be cats however no other vehicle in driveway has ever done this and neighbors cars also do not do this.
    -If I could disable the alarm, I and several other unanswered threads starters would be interested in doing so, however I don’t see any consistent or source on doing so, one says Techstream well I have a Techstream and it’s not an option in the settings. The other says take apart hood cowl and disconnect switch, does that mean I would be riding around with a hood ajar light?
     
  2. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    Also has anyone actually fixed the problem themselves and if so what was the underlying cause of the issue? It seems the majority of these alarm going off threads have speculation but no definitive answer?
     
  3. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    Check/replace the batteries in the FOBs.

    Can also test by turning off SKS at night.
     
  4. bisco

    bisco cookie crumbler

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    test the new 12v and connections. i doubt it is a sticky, seems fairly rare to me. and you're right, no common solution, maybe a wiring issue.
     
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  5. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    12v battery is good oem Toyota battery, I installed it and has a good solid ground can rule that one out. Nothing in the sun glass holder, will replace battery in the fob ASAP and report back.

    For gen 2, I would say it’s common enough to where I even read the dealers had a sticker on a loaner saying don’t put anything in the sunglass holder. There’s even YouTube videos for Tacoma on how to adjust the sensitivity for the same alarm, however for the Prius I cannot find the adjustment control. For this particular generation with this particular alarm, there is more reported false alarm issues than any car I’ve seen.
     
  6. TMR-JWAP

    TMR-JWAP Senior Member

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    My son had similar experiences with our blue 2005, except sometimes it would happen in the middle of a parking lot. Replaced the FOB battery and problem went away for about a month and came back. Battery was weak again. The FOB had holes in the button covers, with some dust/dirt inside, so it looks like maybe a button was sticking. We ended up buying a replacement cover (~$10) and installed a new battery. Problem never came back. If you get a new cover, don't forget to swap the RFID chip also, otherwise the key slot on the dash will not work.
     
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  7. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    I want to say when we got this car a year ago the first thing I did was replace the key fob cover with new one from eBay, something I usually do when buying a used car with worn out fob. I’ll go ahead and order another key Fob cover & buttons if the price is right, to test and inspect the fitment of the buttons.
     
  8. edthefox5

    edthefox5 Senior Member

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    With the fob causing it is the inference the emergency button on the fob is getting stuck? Otherwise can't see how low fob battery is causing it.
    Replaced the fob batteries on my fobs multiple times over 11 years and it never turned the alarm siren on ever. Many a dead fob.

    Most if not all false alarm's going off on a G2 has been a bad 12 volt battery.

    Even though the OP says its a "new" 12 volt battery I would still do a simple load test on it to see how new it really is. May be soft battery.
    Simple quick test will tell.

    With the car off check the 12 volt dc at the Under hood battery jump point. Write that voltage down.
    With car still off turn on the headlights in high beam for 5 mins. .

    After the 5 mins turn the headlights off and wait a minute and then with car still off measure the dc voltage at the front jump point again. If the battery voltage has sagged some its probably bad. My 3 year old optima does not drop 1 volt in this test. My other cars pass this test also.
     
  9. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    Using the Techstream tool I disabled the panic feature from the key fob, then under options enabled security which interestingly wasn’t enabled, not sure why that was the case.

    After that I could access the security menu and turn off the horn for the alarm. Will see if this works, as not sure if it’s the dealer installed alarm I’ve read about or factory alarm and which one of those is and isn’t controlled through ecu.
     
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  10. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    Alarm has yet to go off again, however if it does I will make sure to post back here. So to me seems that you actually can tweak the alarm settings on the Techstream app interestingly enough by enabling security in options(if not already, wasn’t enabled for me) which then allows you to customize the security parameters. Then from the security parameter should have an option for disabling horn on alarm on a gen 2 Prius. Then for safe measure I also disabled the panic feature in the remote menu.
     
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  11. Mendel Leisk

    Mendel Leisk Titanic Social Director

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    Just throw in the towel, turn offf/uninstall/disconnect (whatever it takes) the alarm?
     
  12. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    Well after waking both my wife and I, and neighbors up on several occasions the objective was to stop doing that, so I wouldn’t call this throwing in the towel (as long as what I did fixed it).

    However if I were to drop it off at the dealer and let them diagnose and come up with a costly bill, I would have called that throwing in the towel IMO.
     
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  13. edthefox5

    edthefox5 Senior Member

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    What does the sunglass holder have to do with the alarm?
     
  14. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    #14 JP GEN 2 Prius, Dec 27, 2018
    Last edited: Dec 27, 2018
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  15. edthefox5

    edthefox5 Senior Member

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    Hmmm...What is the windshield security sensor? Is that a glass break sensor?
     
  16. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    Yes I think it is called a Glass Break Sensor, however in the attached PDF the only thing I see if a microphone located under lower dash panel so nothing to do specifically with the windshield. Also in the Prius Alarm Install file I found in a 2006 thread interestingly enough I found the location of the dial to adjust the sensitivity which looks to be located under the "lower dash cover".
     

    Attached Files:

    #16 JP GEN 2 Prius, Dec 28, 2018
    Last edited: Dec 28, 2018
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  17. bisco

    bisco cookie crumbler

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    has anyone taken their car to the dealer for a fix and come away empty?
     
  18. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    Yes three that I could find quickly.
     
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  19. bisco

    bisco cookie crumbler

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    amazing. i wonder if a call to customer service would help get a toyota field rep involved in those situations.

    maybe the alarm itself is bad
     
  20. JP GEN 2 Prius

    JP GEN 2 Prius New Member

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    It’s on the Toyota Tacoma forums too, and I also saw there is a YouTube video showing how to fix the problem on a Toyota Tacoma which involves adjusting the sensitivity. In the Toyota install instructions I see they have step which calls to set the dial to 9, maybe that level of sensitivity was a bad idea for all equipped Vehicles without proper testing.

    https://youtube.com/watch?v=JrD_p5Z--KY
     
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