Alarm going off on its own

[dvlpr Junior Member Find all posts View Profile Close dvlpr]

Hi all,

I wonder if I'm the only experiencing this I had the alarm in the car go off on its own (all doors/windows closed, no animals, etc...) 5 times over the span of 3 days (once at night actually). This is completely random, but so far has happened 5 times during the 2 months I had the car. Once it goes off, it resets the clock and seat/steering wheel memory as well.

I had Toyota do their diagnostics, but they didn't find it and obviously it didn't go off while it was in their workshop.

They told me that there are only 6 sensor in the car - 4 door, boot and bonnet. The only other reason it can go off is if there's a huge drop in battery voltage.

There is nothing after-market in the car so far.

Has anyone experienced this?

[K & M McF Senior Member Find all posts View Profile Close K & M McF]

My non Toyota alarm used to go off all the time. Finally worked out it was caused by taxis using their radio near the car. I turned down the sensitivity of the motion detector and it stopped except when I leave my phone in the centre console.

[dBC Member Find all posts View Profile Close dBC]

The only other reason it can go off is if there's a huge drop in battery voltage.

That sounds like what's happening given your clock etc. are all getting reset. Are the battery connections all secure and clean?

[dvlpr Junior Member Find all posts View Profile Close dvlpr]

My non Toyota alarm used to go off all the time. Finally worked out it was caused by taxis using their radio near the car. I turned down the sensitivity of the motion detector and it stopped except when I leave my phone in the centre console.

I don't have a motion sensor in the car and it's the stock Toyota alarm (or at least they told me I don't have a motion sensor).

That sounds like what's happening given your clock etc. are all getting reset. Are the battery connections all secure and clean?

Well, I haven't checked them myself, frankly. They told me today that they did run diagnostics, which included testing the battery (it's a new car, so hopefully the battery is new too). I'll check the connections tomorrow, but given that the car starts, runs, etc... if they were really loose, I'd expect things to fall apart more often. Perhaps the battery itself is faulty though, but I don't know how to check that.

[yowie Advanced Member Find all posts View Profile Close yowie]

Some alarms over the years in my vehicles have triggered at different times. One was because the window was slightly open and the detection of movement inside the car caused by the wind. Another was due to noisy cars driving past, also thunder during storms. None of these will be likely for you.

Another one was a drop in the battery voltage, as the battery was losing charge and the change in voltage is what triggers the alarm sensors. Possibly yours.

The battery may look good when you drop a voltmeter across the terminals, but when the battery is subject to a stress test, that will detect if one cell is not holding charge.

[dvlpr Junior Member Find all posts View Profile Close dvlpr]

Another one was a drop in the battery voltage, as the battery was losing charge and the change in voltage is what triggers the alarm sensors. Possibly yours.

The battery may look good when you drop a voltmeter across the terminals, but when the battery is subject to a stress test, that will detect if one cell is not holding charge.

I suspect that may be the case. Is there a way for me to stress-test it? Can the dealership stress-test it (I'm thinking maybe I can get them to do it in front of me, just to confirm)?

[yowie Advanced Member Find all posts View Profile Close yowie]

I suspect that may be the case. Is there a way for me to stress-test it? Can the dealership stress-test it (I'm thinking maybe I can get them to do it in front of me, just to confirm)?

Battery shops, such as Battery World, can usually check it.

[dvlpr Junior Member Find all posts View Profile Close dvlpr]

Battery shops, such as Battery World, can usually check it.

Well, the car is sitting in Toyota's workshop and they are waiting for the issue to replicate. Don't know how long it'll take, but I'm obviously not happy I asked them again if they tested the batter and they said that they did test that it holds charge and all the connections to and fro. I'll investigate what battery shops can test and see if I can arrange such a test to be carried out.

[dvlpr Junior Member Find all posts View Profile Close dvlpr]

An update on this - no resolution yet, but at least the service department got a "disrupted communications" error code. Something is not hooked up properly or a component is misbehaving, but at the moment I'm still driving loan cars

[dvlpr Junior Member Find all posts View Profile Close dvlpr]

Ok, got my car back today - hopefully the issue won't happen again. Apparently the reason was the short pin, that wasn't inserted properly. I guess time will tell, but if you experience weird electrical issues, maybe check the short pin and who knows - maybe your pre-delivery guys didn't insert it correctly too.