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Alarm going off randomly

49K views 9 replies 9 participants last post by  bjefrz 
#1 ·
I have a 2008 Prius. About 7months ago the alarm starting going off randomly in the middle of the night mostly occasionally during the day. It was so frazzeling , at first I could hit the panic and it would stop. Then it wouldn't so I would just set the key fob in the car on a seat and that would work and shut it up. Then that didn't work I looked at a few utube videos and put the fob in the fob holder of the car and that worked. It got to be too much and then we took it to the dealer and they said we neeed to replace or keyfobs as one was about corroded inside .... so we did . Things were fine for 6 months and two weeks ago it started going whacky again.
Took it to Toyota and they could not get it to go whacky but noticed the battery was low voltage so we replaced the battery. Things were ok for about 10 days or so and now it's back to its whacky random alarm going off cycle ...... I made an appt for fri 11/4 to ask them to disable the alarm until I have more funds to have them try to now troubleshoot why this is happening. I assume at this point it's something electrical that's draining on the battery and Cassidy the alarm to go off.
Also I do have one rear tire that had a slow leak and I have been adding air and thought I read somewhere where a low tire can cause the alarm to go off in addition to the tire sensor light on the dash but I can't find now where I read that . Going to have the tire repaired today, it may just be conincidental that when ever the tire pressure light is not lit up on the dash the alarm does not seem to go off.
Sorry this is so long but it's my first time and wanted to supply as much info as I have if you got this far THANK YOU for reading
 
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#2 ·
I have finally fixed the problem after putting up with it for 8 months. I tried everything only to find out it was the key fob!! Replaced it with backup fob and haven't happened since. Seriously the alarm went off at least once a day alost 24 hours to the minute. Some days more.
 
#4 ·
I have same problem with a Prius 2008, alarm going off randomly, extremely annoying. Still working in the long term fixing, will try today changing the key fob that is dead and not responding to battery change. To solve the problem temporarily, I kept the car running with everything turn off A/C, lights, etc. Just to pass the night and not bother neighbors. that works, however worried about car deterioration, I kept the car going almost 2 days gas consumption was minimal, not sure if I did any damage to the car though, but I have ridden the car a few times, nothing wrong apparently.
Then, I discover a better solution, keeping the key fob plugged with the car off. For 2 days the alarm haven't gone off at all, before was 3 or more times a day at any time. I know this is not optimal solution, but at least could be a temporary relieve that can make sleep you and your neighbors.
 
#5 ·
My wife just wash the fob with cloth then ran through the dryer till she realized, and we have having same issue now, as follow the temp solution keep the fob in the slot all the time, and use the key to lock the door when needed,,, LOL,,, any updated solution?? We lost the 2nd Fob, so I might need to disconnect the horn before I unplug the fob....
 
#6 ·
I went to Toyota Service, I did not tell them about the alarm problem, I just asked them to get a new FOB which was very expensive by the way. Since then, the alarm has not gone off again for the last 2 months. Curious thing is that they gave me the old FOB working as well. So, I would recommend to tell the service to repair your FOB, it might be a lot cheaper than buying a new one.
Now that you tell the story that happen to your wife, I recall that my FOB went wrong, one day when it was a heavy rain, the FOB got wet and stopped working. Maybe that creates a deconfiguration or something. With this new info, I would give a try expose the FOB to the sun a little bit, and see if that makes any difference. Anyway, wish you good the best luck with that!
 
#7 ·
I had 2005 Prius key fob with this problem - the panic mode going off frequently. Reading Rodrigo's post triggered the thought that reprograming the fob might do something. He described how he bought new key, so dealer had to program new key, and sounds like they may have reprogrammed the old key as well as it starting working again. So, I reprogrammed my bad key with instructions found at link below. Key fixed! Took me three toys at programming before I got the steps right and it completed/accepted sequence. So don't give up after first try if it doesn't work.
 
#8 ·
I have a 2007 Prius and had the problem of the alarm sounding randomly. I eventually found out why. I am not in the habit of having my phone in my pocket all the time, and for the same of comfort I would place it in the centre console. On l parking the car I would occasionally forget that my phone was still in the console. From that moment if my phone received an email or any message it triggered the alarm. I tested this several times and had a friend send me messages by various means and each time the alarm was triggered. DON'T LEAVE YOUR PHONE IN THE CAR !!
 
#10 ·
I had a dead battery in my fob and when I replaced it with what I thought was a fresh battery, the panic alarm went off immediately. And would continue to do so randomly every few minutes. Long story short, the “fresh batteries were new in the package but old. Put an actually fresh battery in and it works like a charm.
 
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