Prius alarm goes off with no reason

Welcome aboard.

Did you do any recent repairs to the door locks and or do they work properly? Sit in the car and use your remote to see if the locks go into lock position when alarm is activated.

 

Best way to keep from setting off the alarm accidentally...



Bill the Engineer

 

Maybe William should tell us if he has a Prius gen 4, Prius gen 2. If he has a key fob with an alarm button, then Bill's solution should work.

 

Or tell us if it is an aftermarket alarm system...

 

Is this even factory alarm or some aftermarket one? Or is it just panic button on key?

Especially if it’s some aftermarket one test your 12V battery (you can find instructions online how to test gen 2 Prius 12V battery easy without any tools) Aftermarket alarms are sensitive for 12V battery problems and since Prius can work with pretty bad 12V-battery it could be the reason.

 

Aftermarket alarms usually have their own siren. Since you mentioned the horn, I'm inclined to think you are pressing the panic button on the fob by accident or it is faulty. Very easy way to test. Take the battery out of one fob and see if it goes off. Repeat for the other fob.

 

OP, have you or someone else changed the fob battery lately?

The panic button may be stuck, and was caused when reassembling the fob case improperly.

 

Post a picture of your remote

 

Would it be unreasonable for you to disconnect and remove that alarm?

 

I don’t care about the 12v battery or key fob. I just have 1 simple question.

How do I totally disable the factory car alarm and still have normal horn function?

 

I love how nobody answers on this forum, they just keep typing about whatever

I've been trying to fix this same problem for years, and nobody knows, but nobody days, "I don't know"

 

Generally speaking, people who don't know do not post anything. It would serve no purpose for 20 or 30 people to post "I don't know" posts, except to fill the thread with unnecessary clutter.

 

Perhaps you should ask Danny for your money back since the forum does not provide the expected level of service.

 

One thing to do would be to check that the fobs are not at fault. Taking the battery out would be best, but that's a PITA. So instead try rolling them up in several layers of aluminum foil to block the RF when you get home. Do a positive control - press the alarm key through the foil to verify that the signal is really blocked. If the alarm still goes off at night while they are blocked like that then the fobs are not the problem. If you are "lucky" the alarm will not go off. Then you can see which one is at fault, by wrapping them one at a time. Honestly I doubt this is it, but since this is so easy to do, you should at least rule out the possibility. Also if the alarm only goes off once a week, or something like that, you will have to run this experiment for a very long time.