C70 alarm triggered by outside vibes
 

'06 C70 frequent false alarm

The alarm can be triggered by vibration from outside: passing (loudish) motorbike or lorry, etc.

Sometimes it just goes off for no apparent reason: I understand from other posts that this can be due to a duff siren battery et., however, I want to concentrate on its being over-sensitive for now...

No dangling wires etc. in the passenger compartment.

If I could find the ultrasonic (I assume) transmitter or receiver, I'd try covering either with some light material to try and mute the sensitivity.

Any bright ideas?

Have you not got the reduced guard function on your alarm? If so have you tried it and does it make any difference?

This is of no help whatsoever, but two doors down from my parents own a v50 similar to mine, and when I operate my central locking it triggers the alarm on that car.

Thanks for the reply.
It would appear not. I've been through the menu and as far as I can see there's no alarm options.

BTW, I've just discovered it's a microwave set-up, not ultrasonic. Supposedly so it works with the roof down... :confused-smiley-013 So I guess it'd be back to the tin-foil (with matching hat).

My v50 does the same, if I do not disable it when I leave the car, the internal movement sensor triggers the alarm. If is too sensitive or defective, I do not know.
I do not mind deactivating/disable it. Every time I disable it, I get info. as "reduced guard, see manual"

There is a button up near the map lights that reduces guard?
I was getting random alarm triggers on mine, replaced the alarm siren internal battery, that lasted about 10 months then I got the same symptoms again, ended up replacing the siren module with a new one, has been fine for the last 18 months.

alarm
 

hi,

could be issue with low battery in side the siren module

Phone
 

My last mobile phone if left in the car used to set the alarm off!

(Belated) Thanks for the comments there, chaps.

On our other Volvo, wires dangling from the rear-view mirror (for dashcam) if wobbled could trigger the alarm. So on the C70 we were leaving them on the centre-console, seat or floor. AFAIK, the C70's sensor is aimed exactly there, below window-height (as I mentioned above: so it can be used with the roof down), so if they wobbled, they'd trigger the alarm. By tucking any wires away, we seem to have dramatically reduced the number of false alarms.

Still gets excited by loud motor bikes and reverberating lorries though.