Car alarm keeps going off randomly usually at night

[Daniellex]

Hi my car alarm keeps going off randomly at night I turn it off and it goes off again I called Toyota and they told me locking it with the physical key will stop this but I have just done that and it still went off after. It’s very frustrating and sometimes when it goes off it turns on things in the car a drains the Battery. Is there any way to get rid of this alarm because I’m completely sick to death of it waking me up in the night writing this now as it has for the hundredth time. No one is tried breaking into it. It does seem to be when it’s parked in uneven ground but surely it isn’t that sensitive that would be ridiculous. Ideally want to remove the alarm or stop it completely if that’s possible sick of it!   IQ 2009 REG

[PCM]

Water getting in?

Maybe locate an auto electrician to check?

Any 'codes' to read?

Alarm? Is it an aftermarket alarm on the IQ horn?

[DAF XF]

4 hours ago, Daniellex said:

Hi my car alarm keeps going off randomly at night I turn it off and it goes off again I called Toyota and they told me locking it with the physical key will stop this but I have just done that and it still went off after. It’s very frustrating and sometimes when it goes off it turns on things in the car a drains the battery. Is there any way to get rid of this alarm because I’m completely sick to death of it waking me up in the night writing this now as it has for the hundredth time. No one is tried breaking into it. It does seem to be when it’s parked in uneven ground but surely it isn’t that sensitive that would be ridiculous. Ideally want to remove the alarm or stop it completely if that’s possible sick of it!   IQ 2009 REG

I had this on an older auris a few years back and feel your pain. Totally random and always at night for some reason for a couple off weeks. Then one day I happened to spy a small spider that had appeared up near the head cloth/sensor section. Having cleared it from the car the alarm never sounded again. Long shot but just keep n eye out for something that simple. 

[Bper]

Hi Danielle, Given that the alarm seems to be triggered when the car is parked on uneven ground, the most likely cause could be a sensor or switch within the alarm system that is overly sensitive to motion or changes in the vehicle's position. This sensitivity could be exacerbated by the uneven ground, causing false alarms. It's also possible that there could be a wiring issue or a malfunctioning component within the alarm system itself.

Have you checked the Battery as it may be low and this can lead to Voltage issues with a number of electrical systems within the car. How long ago was the Battery changed or checked, unfortunately with this type of problem it can be a number of issues that can cause this. It may not be your first choice but you are probably better taking it to a dealer or a auto electrician who will be able to pinpoint the exact cause of the problem. Hope this helps.

[Moleman]

Check for insects, particularly those that fly at night.

[Mooly]

Is there a bonnet switch to detect forcing the bonnet open?

This was a common issue on the older Corolla and the alarm going off randomly was actually caused by minute movement of the bonnet as it cooled and contracted. The switch on the Corolla was at the back edge of the bonnet. The fix was super simple... quickest and easiest way was to stick a small piece of plastic to the underside of the bonnet where the switch plunger made contact with bonnet to ensure the plunger was pressed in a little more. Even 0.5mm would have been enough. You could also quickly unbolt the switch and elongate the fixing hole to allow it to be repositioned a fraction higher.

[Pete.Z]

Was there a standard factory alarm on the IQ, or is it aftermarket?

[Ice Quartz]

Aha, I had the exact same problem which drove me and all the neighbours mad and yes it was worse when I parked on uneven ground or a slope!  After quite a bit of trial and error it turned out to be connected to the boot opening mechanism.  I bought a second hand one on eBay, changed it and have had no problems since 😃

[flash22]

If it is the toyota upgrade or aftermarket alarm, is usually a sign that the Battery backup in the sounder is dead/dying

if it is the bog standard alarm that honks the horn make sure your interior light works correctly from both doors and if you have a light in the boot check that is working too

 

apart from that go get your 12v Battery tested - if the voltage drops off, especially on a colder nights it could trigger the alarm and do other weird things like turn the headlights on (auto lights)

[PCM]

On 4/12/2024 at 3:23 AM, Daniellex said:

Hi my car alarm keeps going off randomly at night I turn it off and it goes off again I called Toyota and they told me locking it with the physical key will stop this but I have just done that and it still went off after. It’s very frustrating and sometimes when it goes off it turns on things in the car a drains the battery. Is there any way to get rid of this alarm because I’m completely sick to death of it waking me up in the night writing this now as it has for the hundredth time. No one is tried breaking into it. It does seem to be when it’s parked in uneven ground but surely it isn’t that sensitive that would be ridiculous. Ideally want to remove the alarm or stop it completely if that’s possible sick of it!   IQ 2009 REG

Any more thoughts on what you might do? Has the issue occurred again? 

[We-go]

Just a suggestion. I had this problem some years ago. It turned out to be the bonnet flexing with change of temperature and the alarm switch activating. I stuck a coin to the underside of the bonnet where the switch made contact and the problem vanished.

[PCM]

Sadly, I think the OP has 'left us'.... 

[We-go]

Ah, yes!