Alarm Trouble! Sensor, or Module? I have VIDA...

[yoda960]

Hi Chaps

I've been doing a bit of work on my 2005 V70, had the battery disconnected whilst doing this as I gave it a bit of a charge as i've not used it much the past few weeks.

Anyway, got everything put back together and re-connected the battery. Locked the car and the alarm went off. This happens every time I lock it, it seems fine for two seconds, then straight after the secondary locks click in, the siren sounds and the lights flash.

The weird thing is that the siren is very very low in volume.

The dash reports a message along the lines of "Alarm triggered, check car"

I have had issues with the Alarm before, going off randomly. I cracked open the module and replaced the battery (about a year ago). The issue then went away.

I have VIDA, it gives the code:

UEM-0004 Siren Communication Fault

Does this mean it's the siren module that's beggared up again? This is confusing given the message in the car reading "Alarm triggered, check car". Surely it's a sensor that's been triggered, not a communication fault?! But if it were a sensor, why is the alarm siren really low in volume? Weird...

Anyone know if VIDA will give any more info on which sensor it is, if it is a sensor that's been triggered?

Whilst I was working on the car, a sudden (unexpected!) gust of wind blew the bonnet shut. I did think maybe it was something related to bonnet sensor, but I couldn't see any sensor info in VIDA.

Any thoughts from you chaps would be dearly appreciated! Bloody new Volvos, they really test the patience!!!



EDIT: Anyone know the fuse/location of the alarm? I might pull it because I don't have time to investigate for a couple of days...

[yoda960]

This was the battery I used when I replaced the knackered one in the siren module a year ago:

https://www.ebay.co.uk/itm/Battery-N...kAAOSwZrhaWvzr

It's a decent battery, so I don't see how it's failed in just one year.

Does anyone know how the battery in the siren module charges? Does it only charge when the alternator is running, or is it always connected to live?

I'm wondering if it's somehow gone flat with lack of use. I did take it for a good hour drive after the work but still same result.

[t4owner]

If you go into cem or rem advanced it will give you alarm causes
Not sure your car has alarm siren fuse at end of dash on a 05 car

[outnumbered]

could be the one above your head in the roof liner the big square
plastic sensor that can trigger this issue
you can get a good second hand one for about a tenner ,plug and play.
mike

[Brendan W]

A car with the siren fuse pulled will have a permanent UEM-0004 but no dodgy activations.
The alarm will trigger if you leave the dog in there and you will get the triggered message.
I'd be inclined to give the bonnet a good slam shut. It's the one that generally causes most issues.

[SwissXC90]

Could be that while the main battery was disconnected the alarm battery discharged to nothing.
Leave the main battery on for a while - a week or so - to give the alarm siren the chance to charge its internal battery

[yoda960]

Thanks for all the suggestions and help chaps, really appreciated.

t4owner - thanks for telling me about going into CEM! I found the alarm cause section and it says alarm siren voltage drop so looks like it was the battery in the module...

The battery was only disconnected for a day or so, so i'd hope the year old battery would have lasted. Maybe you are right though SwissXC90 - I should give it a week or so to see what happens (would need a week anyway to order another battery). I wonder if the alarm battery only charges when the engine is running.... can anyone confirm?

[Montana]

Been having an issue with my V50 with the alarm going off (here)

I pulled FUSE F56 under the passenger footwell which was the siren - fixed the problem but my car wouldnt then lock.

If theres no side affects i am tempted to disconnect it completely

[Simon Jones]

Originally Posted by Montana

If theres no side affects i am tempted to disconnect it completely

Only to your insurance premium