Alarm Going Off Random

[Johndcfc]

Hi All,

In the past two days my alarm has gone off by mistake while in car parks (not at home) - anyone else had problems with the corolla alarm?

Thanks

John

[MarcTS]

I haven't had a problem with it going off by accident, but it always goes off when I wash my car, as soon as I put anything but feather touch pressure on the centre of the roof, the alarm goes off. I bought the car second hand from Mr T and it didn't come with an owner's manual, and I asked for one at the time and they said they'd order it for me, but I got busy with work and never hassled them over it again.... that was 10 months ago.

So I don't know if it's possible to lock and immobilise the car but disable the actual alarm.

[Bodgit]

the alarm does seem to be over sensitive. i have noticed this when washing the car. after i have done the was and am on to drying and polishing i open one of the doors to stop the alarm going off.

[chrisio]

On my old T-Sport I never had issues with false alarms but it did occasionaly ignore the remote control when it was parked at work.

I changed batteries and even tried the spare key but eventually found that the Orange cell mast on top of the building was interfering with the remote receiver

Makes you wonder what the signals are doing to our brains ;)

[Panners]

Bonnet catch perhaps?

Mine was forever going off as the temperature rose through the day. Dealer put it down to that and looked at it three or four times, but as ever, didn't cure it...

[Rinko]

This may sound stupid, but was it in supermarket car parks?

I know some supermarkets have magnetic loop systems around them which cause the trolly wheels to lock when you try and take them off site.

I've heard of people having problems with the systems and thier car alarms/remote fobs etc.

[nrgizerbunny]

if you figure out what sensor is triggering it that would be of use. you'll get a series of flashes when you put the key in the ignition.

if its the interior sensors, you can turn the pot down on the microwave. otherwise it is likely to be the bonnet pin switch.

[toyota rally]

had loads of snags with mine in the two years Ive had it, first time it went back to have a check they could not find any snag so they said they changed the sensors . work for a while. and replaced the horn as it had worn out it had gone of that much. not a joke it sound like it had a flat Battery it was that bad it stopped working even when you pressed the horn.

then it started doing it again over the last few months. took it in and they found a fault with the bonnet catch sensor. replaced it and it hasn't gone of since.

[MJG]

Hi All,

In the past two days my alarm has gone off by mistake while in car parks (not at home) - anyone else had problems with the corolla alarm?

Thanks

John

John This is a well known issue., I've just done a forum search to pull up previous posts on this but to no avail.

I had exatly this problem but have cured it. The solution was found in this forum so I can't take any credit for it. but it is linked to the bonnet switch. Apparently the bonnet changes shape as it cools after a run an at the back edge lifts very slightly, thus activating the bonnet alarm switch (in the same way as if someone had 'popped' the bonnet).

The solution is simple, attach a disk of approx 2-3mm thick to the back edge of the bonnet where it makes contact with the alarm switch.

Will this work?????

I got my t-sport nearly 2 years ago, within a week or so I was getting 4-5 false alarm activations per week. I did a search here, found the suggested solution, did what was suggested and I haven't had a problem since.

[ObanScot]

good job

Toyota no fixed yet.....

after 5 years....

[Jock Fran]

Thought I'd bump an old thread to save starting a new one...

My alarm has gone off a few times (3/4 since getting the car) for no apparant reason. Sounds like it could well be the bonnet sensor causing it.

Does anyone know how to tell which sensor triggered the alarm? Something like counting flashes on the security light on the dash?

Cheers!

[corroded]

Yeah, this isn't totally coincidence that the day after i lift my bonnet for the first time i've had my car alarm going off numerous times :(

[750turbo]

Hi All,

In the past two days my alarm has gone off by mistake while in car parks (not at home) - anyone else had problems with the corolla alarm?

Thanks

John

John This is a well known issue., I've just done a forum search to pull up previous posts on this but to no avail.

I had exatly this problem but have cured it. The solution was found in this forum so I can't take any credit for it. but it is linked to the bonnet switch. Apparently the bonnet changes shape as it cools after a run an at the back edge lifts very slightly, thus activating the bonnet alarm switch (in the same way as if someone had 'popped' the bonnet).

The solution is simple, attach a disk of approx 2-3mm thick to the back edge of the bonnet where it makes contact with the alarm switch.

Will this work?????

I got my t-sport nearly 2 years ago, within a week or so I was getting 4-5 false alarm activations per week. I did a search here, found the suggested solution, did what was suggested and I haven't had a problem since.

Me too, but Dealer cured it by adjusting Bonnet Switch some way, hasn't went off again, then again it has been !Removed! raining every day for the last two months

[Ed_Shek]

I've had a couple of false alarms recently but I think that was due the next door neighbour brushing against the car on the drive. Does the problem mainly affect pre-facelift or facelift Corollas?

[chrisio]

I had my first false alarm on my Compressor this Sunday

The sun was really hot on it outside my garage so I wonder if the earlier posts about the bonnet deforming in the heat is relevant.

I'll try the 'packing the bonnet sensor' trick to see if it works

[Jock Fran]

Mine has gone off a couple of times recently under similar conditions.

Getting home, leaving the car for about half an hour (once to swap wheels over, once because the drive was blocked), then moving the car onto the drive.

I've just put a screw in the underside of the bonnet where it touches the sensor, so it will be interesting to see if it cures it.

I can't see why it would only happen after leaving the car for a bit and then moving it again.

I've had it happen previously under similar conditions but just going back to the car to get stuff out after about half an hour, rather than moving it again.

Does the alarm reset where it thinks the bonnet switch is at some point or something? Seems odd!

[chrisio]

I stuck a foam pad under the bonnet where it touches the alarm switch and it seems to have cured it

[Shamus12]

Recently bought my Toyota carrolla tsport had it over a month this last couple of weeks the alarm has randomly been going off ,🤔🤷‍♂️ I'm trying to eliminate the causes so if anyone can help?? I know the car was stood for some months before I bought it and the guy said it may not start but it did.. obviously with the cold wheather iv been using heater system and charging my phone., I have been told it could be a faulty or low Battery causing the alarm to go off