you will probably find the code relates to no communication with the siren in which case a new siren is needed .

Would it still sound if there was a comms fault?

no because it would not get the message down the single data wire to sound .. and it could go off on it's own if the circuit board was corroded somewhere .

That's what I thought, so as the OP said the "siren works perfectly" (by which I took to mean it makes a noise when triggered) it would reasonable to assume the wiring was in good order.

Get Your codes looked at?
 

So how do I do this without paying volvo dealership hundreds of pounds??

Yes my alarm siren works perfectly. When I lock the door on the fob , but open the door with the key and open the door, the siren sounds and indicators flash. I am satisfied that the siren is fine. It's just the "Alsrm System Service Required " message I need to get rid of!!

Any help appreciated

you need to get the fault codes and the last alarm cause read out .. then if the codes relate to a communication problem with the siren you will need a new siren unit .. about £160 I believe .

Thanks Clan. Is it only Volvo dealers that can "get the fault codes and the last alarm cause read out"? A visit to a Volvo dealer can be a gut wrenchingly expensive experience - although am loath to invest £183 (on ebay) for a new siren unit - when the one I just took out and changed the battery in works perfectly well as an alarm and a siren. I just want the "Alarm system Service Required" message to disappear! I want someone with a code reader within easy reach of Witham Essex that can connect to my 2006 V70 D5 and delete this alarm system Service Required message (or alternatively a recommendation of a low cost reader that I can buy and conmnect to the car to do it myself!). Or is this impossible?

I don't believe you can delete that message as it not one that is stored. It is indicating a live fault (rightly or wrongly) so it does seem like you need to have the codes read which might pinpoint a fault with something like the mass movement sensor or tilt sensor (if fitted).

Thanks
 

Oh I see. It's possible that something else maybe broken? Something that has no obvious to the performance of the car??

I've just ordered a new alarm kit from Skandix.de. It's a genuine Volvo kit (Part No 9499758) all for 183 euros including courier delivery This is around £136 -£137 at current exchange rates which is a good saving over UK prices.
Here is a link.
http://www.skandix.de/en/spare-parts...n-kit/1029734/