Prius alarm will NOT stop!

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Alecjoel, Mar 10, 2016.

  1. Alecjoel

    Alecjoel New Member

    Joined:
    Mar 10, 2016
    8
    0
    0
    Location:
    Seattle
    Vehicle:
    2006 Prius
    Model:
    N/A
    Hey all,

    My wife and I own a 2006 Prius (trim level 3) with ~160xxx miles. We had the battery replaced about 3 months ago and have not had any issues.

    2 days ago, the car alarm went off around 1am and wouldn't shut off. Over the next few days the alarm would randomly trip, turning on again as soon as the panic button was pressed on the key fob. Locked, unlocked, battery in/out of the fob, the alarm will just turn itself on. The Toyota dealership was baffled and could not help.

    I have spent the last 6 hours this morning trying to find a solution and coming up with nothing. Has anyone else had an issue with this? Any help would be welcome - my car will be impounded if it keeps this up.

    Thanks
     
  2. kenoarto

    kenoarto Senior Member

    Joined:
    Feb 7, 2006
    1,275
    317
    0
    Location:
    Chicago, IL
    Vehicle:
    2005 Prius
    Model:
    II
    Have you taken batteries out of both fobs and replaced them with new batteries? Rechecked and cleaned the battery connections by brushing them with a wire brush and tightness?
     
    #2 kenoarto, Mar 10, 2016
    Last edited: Mar 10, 2016
  3. Alecjoel

    Alecjoel New Member

    Joined:
    Mar 10, 2016
    8
    0
    0
    Location:
    Seattle
    Vehicle:
    2006 Prius
    Model:
    N/A
    All of the above. The alarm will even go off with the batteries out of the fobs, the only way I could disable the alarm was to keep the car running.
     
  4. The Electric Me

    The Electric Me Go Speed Go!

    Joined:
    May 22, 2009
    8,676
    5,257
    0
    Location:
    Undisclosed Location
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Has the alarm gone off unprovoked in any other location besides being parked at home?
    Or maybe more simply does this happen everywhere?

    Surprised the dealership had no suggestions. Even if that suggestion turned out to be, the whole system is shot.

    Sorry I can't be of more help. Good Luck tracking down and solving the problem
     
  5. kenoarto

    kenoarto Senior Member

    Joined:
    Feb 7, 2006
    1,275
    317
    0
    Location:
    Chicago, IL
    Vehicle:
    2005 Prius
    Model:
    II
    I had a VW Rabbit with annoying electrical problems. Took a year to chase down the random starting problem. Turned out to be a burnt fusible link along the side of the hood. You know, a 99 cent fix. Check and clean all your fuses?
     
  6. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    84,629
    37,224
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    welcome! which battery was replaced, hybrid or 12 volt?
     
  7. 48mpg

    48mpg Member

    Joined:
    Nov 5, 2015
    193
    46
    0
    Location:
    florida
    Vehicle:
    2005 Prius
    Model:
    I
    lock and unlock the drivers door with the metal key a few times, it might reset the system.(worked on an old ford I had)..might try cycling the car on and off a few times with the fob in the dash...
     
  8. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    3,835
    1,994
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2006 Prius
    And have you checked the state of health of the 12 V battery as well as the connections of the negative to the car body? All clean and tight?
     
  9. Alecjoel

    Alecjoel New Member

    Joined:
    Mar 10, 2016
    8
    0
    0
    Location:
    Seattle
    Vehicle:
    2006 Prius
    Model:
    N/A
    Thank you for your responses! Here is what happened so far..

    I checked the fuses, all are clean and functional. Both batteries were replaced in December, and all connections are clean. I pulled the fuse for the horn in hopes of a temporary fix while parked at home, but it started acting up again tonight.

    An interesting thing I noticed is that it does not happen when we are away from home. 4 hours at a hospital, 6 at work, grocery store, etc. and no issues. That would lead me to believe it is a location based event, yet it does not go off 24/7 so I do not know what triggers it. Thoughts? I'm about to just disconnect the battery when it is parked at home so the HOA won't tow it.
     
  10. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    3,835
    1,994
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2006 Prius
    Has a phone company installed a new cell tower, upgraded an existing cell tower to 4G or increased the power output of an existing cell tower nearby where you live three months ago?
     
  11. Alecjoel

    Alecjoel New Member

    Joined:
    Mar 10, 2016
    8
    0
    0
    Location:
    Seattle
    Vehicle:
    2006 Prius
    Model:
    N/A
    No, nothing. My neighboring car in our carport is a Prius V, he has no issues. We are one of about 4 different prius' in the complex and the only one having issues.
     
  12. The Electric Me

    The Electric Me Go Speed Go!

    Joined:
    May 22, 2009
    8,676
    5,257
    0
    Location:
    Undisclosed Location
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A

    Well that's why I asked.
    And that's huge.

    Obviously something in your area is now intermittently triggering your alarm.
    I suppose it could be a cell tower or who knows?
    I wonder if your system could be reprogrammed to accept a different frequency or code?

    Curious however, because I can't really remember reading a thread where somebody had a "rogue" signal triggering their alarm system. BUT that does seem to be what is happening in your case.

    I'd call the dealership and present this specific theory. See if they have any ideas as to how to possibly counter this reality.
     
  13. Alecjoel

    Alecjoel New Member

    Joined:
    Mar 10, 2016
    8
    0
    0
    Location:
    Seattle
    Vehicle:
    2006 Prius
    Model:
    N/A
    I am tempted to pull the theft deterrent fuse, but according to the manual it also controls the smart entry and start, Windows, multi info-display and the power steering. ☹
     
  14. Alecjoel

    Alecjoel New Member

    Joined:
    Mar 10, 2016
    8
    0
    0
    Location:
    Seattle
    Vehicle:
    2006 Prius
    Model:
    N/A
    I have called the dealership and they plugged into the car and tested it every way they know how, nothing. They recommended unplugging the 12v battery when it is not in use but that is not good for the car or battery, and it is not something feel like doing twice a day!
     
  15. The Electric Me

    The Electric Me Go Speed Go!

    Joined:
    May 22, 2009
    8,676
    5,257
    0
    Location:
    Undisclosed Location
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    When you called the dealership did you tell them you thought that perhaps a rogue signal from an outside source was setting off your alarm?

    Because if not, then hooking it up to the dealership diagnostic tools is just going to reveal that the system is actually working. There's nothing wrong with it, it's just picking up a signal from around your home.

    To be honest if that's the case I'm not sure what could be done. But as you say there are other Prius around and they aren't manifesting the same symptoms. Which would lead me to believe perhaps a code or frequency change might fix the problem. I know from threads where people have lost their fobs and replaced with new, that the system can be reprogrammed to accept a new signal. I don't know if the system can be reprogrammed to accept a new signal from an old or original fob.

    Good Luck.
     
  16. 48mpg

    48mpg Member

    Joined:
    Nov 5, 2015
    193
    46
    0
    Location:
    florida
    Vehicle:
    2005 Prius
    Model:
    I
    I found this on disabling the alarm system

    Thank you for your patience and waiting. I think we can do this one of two ways. One is through the Dealer and involves using the Techstream scantool. There are several features that can be customized to prevent the noise aspect. One will deactivate the horn from being sounded to warn that the car is being broken into. The lights will still flash but no horn.



    The second method involves disconnecting the hood pin switch. It is connected to the hood latch and is a 2 pin (wire) connector that when disconnected lets the body computer 'think' that the hood is open thus the alarm will not activate in preparation for security. You will have to remove the plastic cover and access the hood latch and disconnect it.

    if this only happens where you live then its either cats jumping on the car or someone has the other fob pressing the panic button to screw with you.......or you live on radioactive waste..... good luck
     
  17. Ginny K Shulka

    Ginny K Shulka New Member

    Joined:
    Sep 30, 2018
    1
    1
    0
    Location:
    La crosse, wi
    Vehicle:
    2005 Prius
    Model:
    Base
    I had this problem too. What I ended up doing was to replace the micro switches on the key fob circuit board. First it was the alarm button, then the lock button, and finally the unlock button. They just failed over time. I felt comfortable enough to desolder/solder new button switch. That fixed the problem.
     
    bisco likes this.
  18. tomnmeg

    tomnmeg Junior Member

    Joined:
    Sep 28, 2007
    22
    10
    0
    Location:
    Peoria, AZ
    Vehicle:
    2016 Prius
    Model:
    Four Touring
    Yeah, your FOB's may be worn. What's odd though is you said you took the batteries out, and it still went off. Well, hop you got that resolved. Good luck.
     
Loading...