Alarm Has Become Very Sensitive (04 Prius)

[Hernibles]

Hello,

Our 04 Prius' alarm has become very sensitive, to the point where a loud vehicle will ALWAYS trigger it when it passes...especially "boomy" vehicles such as Subarus, trucks or Harley Davidson motorcycles.

We have got in the habit of pressing the override button (under the steering column) to prevent this happening.....but really we want a more permanent solution.

Q1. Does the override button disable all the alarm sensors (including bonnet and boot), or just the internal ultrasonic?

Q2. Does anybody have any inside knowledge on how to disable the alarm completely and permanently? It seems there is no one fuse I can pull to achieve this.

David

[Chris Dance]

Suggest you get Toyota dealer to reset the alarm so it works correctly. I wouldn't leave a car anywhere these days without the alarm being armed. Why would you want to disable the alarm permanently? It is your deterrent against thieves. Would you be insured if your car was broken into and you had not set the alarm? I do not think you would be insured especially if you had purposely disarmed your car alarm..

[Jan&tone]

I agree with Chris, I wouldn't leave a car anywhere without the doors locked and the alarm on. Most people don't take any notice of car alarms now, but at least the scroats have to hurry up!

[korat102]

I had to have the head unit changed on my 2005 Prius after the alarm starting going off for no reason at all. I'd completely forgotten about that. They did it at the same time as a service so obviously not a huge job.

[Hernibles]

I had to have the head unit changed on my 2005 Prius after the alarm starting going off for no reason at all. I'd completely forgotten about that. They did it at the same time as a service so obviously not a huge job.

Having done a bunch of research, it would appear that the ultrasound sensor is above the small storage box in the roof, right next to the courtesy lights, and the alarm can be triggered by vibrating "stuff" inside. We had an AA card and some other bits loose in there that I suspect could easily vibrate in the presence of low frequence vibrations. Have taken those out and will see what happens. If there is still some sensitivity the next experiment will be to pack a piece of foam in this storage space, and duct tape over the small alarm vents.

I have no hangup about completely disabling the alarm if necessary...incidentally I also found the relevant part of the service manual here: http://www.hybrids.ru/PriusNHW20/rm/rm1076e/m_05_2224.pdf It looks like this sensor will be easy to electrically test, and either disable or replace as necessary.

David

[Chris Dance]

I had forgotten that if you put anything in the storage box in the roof above the the front windscreen the alarm gets triggered. This problem was discussed before when folk stored sun glasses in that storage box.

[sjrainsford]

Yep, I had the very same problem. It seems to be metal framed sunglasses that set my alarm off. Plastic ones don't seem to affect it. And yes, it's always when vibration is caused such a from a noisy passing car.

[Kasheera]

Have anybody got a solution for this issue of too much sensitive shock sensitivity ?

[MyOpinionIsWorthless]

On 9/8/2011 at 3:26 AM, sjrainsford said:

Yep, I had the very same problem. It seems to be metal framed sunglasses that set my alarm off. Plastic ones don't seem to affect it. And yes, it's always when vibration is caused such a from a noisy passing car.

Metal frames sunglasses. Seriously ?