Alarm sounding for no apparent reason

[Russ77]

It could have just been a one off blip but thought I'd just ask the question to try and prevent 3am wake-ups for me and my neighbours.

 

As usual, I got in from work around 16:30, parked on the drive, locked the car and went indoors.

 

Around 8pm the car alarm went off.  I got out there ASAP (must have been less than 10s), turned the alarm off and checked up & down the street for anyone who may have tampered with the car.

 

No obvious signs of any interference, I unlocked & locked again and it didn't go off overnight.

 

I first thought it might have been voltage drop, my scangauge was showing 11.7v before I started it this morning but it returned to 13.8 on idle and over 14 when running.  It started fine although I know batteries can just fail without warning as soon as the weather gets cooler.

 

The car was registered in December 2014 and AFAIK it's the original battery but it was quite happy to use stop/start mode this morning on the way to work.

 

My next step might be to disable the interior movement sensors to eliminate them as the cause if it happens again.

 

Is there anything else I can check, I'm guessing without the ODB diagnostics software there's no way of knowing what activated it?

 

TIA

 

Russ

 

 

 

 

[keithfh]

Mine goes off regularly when the sat nav falls off the windscreen 

[Adrian55555]

At a guess i would say its the actual alarm siren/unit thats on its way out.  I have had this on my prev vw and it started off like yours justa once off and over time it started to do it more. 

[Russ77]

9 minutes ago, Adrian55555 said:

At a guess i would say its the actual alarm siren/unit thats on its way out.  I have had this on my prev vw and it started off like yours justa once off and over time it started to do it more. 

 

I'd totally expect it on an older car but sure not so soon on a car that's not even 4 years old yet? 

[Adrian55555]

Mine went in around that time. But i have seen many go whilst still in warranty.  But you dont think much of it as u dont pay.  Things can go wrong from day 1.  

 

Get it plugged in to confirm. It may just be a one off. 

[gregoir]

Now that it's autumn, lots of spiders are everywhere.

My Octavias went through spells of non recurring false alarm triggering. Sometimes on camp sites.

No idea why.

[Russ77]

Just now, gregoir said:

Now that it's autumn, lots of spiders are everywhere.

My Octavias went through spells of non recurring false alarm triggering. Sometimes on camp sites.

No idea why.

Now that was another thought I had as there are webs appearing on a daily basis but I thought I might get laughed at for thinking it 

[bouff34]

21 hours ago, Russ77 said:

 

I'd totally expect it on an older car but sure not so soon on a car that's not even 4 years old yet? 

 

 

I have 2014 Octy and printed off various service stuff from Erwin when I first got it. There was a replacement interval of five years for the alarm battery (which entails replacing the whole alarm unit anyway (I believe)...however, when I recently looked at Erwin again this seems to have been extended now to a six year interval...possibly because the whole process for replacement looks like a pain in the backside and you wouldn't want to do it unless really necessary...!

 

So less than 4 yrs would seem a bit early for it to be on its way out...

[KevC_Derby]

On ‎26‎/‎09‎/‎2018 at 12:08, Russ77 said:

Now that was another thought I had as there are webs appearing on a daily basis but I thought I might get laughed at for thinking it 

 

I had a moth in mine last week that set it off! 2018 Mk3FL

[ords]

1 hour ago, KevC_Derby said:

 

I had a moth in mine last week that set it off! 2018 Mk3FL

It's really that sensitive?

[KevC_Derby]

It was a right big ba5tard!

[Skaut]

Yes, some of them can be pretty monstrous, moths, spiders & large flies have all set mine off in the past.  I regularly work in woodlands with the rear hatch open get all kinds of stowaways.