False Alarms

[Willow]

I got my V50 in March 05 and from day one I had the problem that the alarm would trigger when I closed or opened my garage door. I worked out that the microwaves from the mass movement sensor (MMS) were leaking out the back window and then bouncing off the door back to the sensor and causing the alarm. I reported the fault to the dealer and Volvo and then forgot about it until now (just got into the habit of arming/disarming with the door closed).

Decided to finally get it fixed, dealer fitted a new MMS but this morning the alarm triggered as I opened the door :hissyfit:

Anyone else have this or a similar problem?

[ptecuk]

Had exactly the same problem with my 2005 S40 2.0D SE Sport. The dealer initially had a go at fixing it by checking connections I believe. This did not cure the problem. In the end the dealer changed the MMS for what they said was a less sensitive unit and it has been ok since. When I originally had the problem I demonstrated it by waving a sheet of kitchen foil over the back window. The alarm would also sometimes be triggered by passing cars when parked in town. It was obviously sensitive to movement of large metalic objects. Before it was cured by the dealer I temporarily got round the problem by unclipping the sensor in the roof and carefully shielding the unit inside with kitchen foil. However, it should be fixed under guarantee.

[Willow]

Thanks PTECUK that's useful. I think I now have the less sensitive MMS as I had to wave my arms around a lot more to trigger it when I tested it :Banane32:

I will ask the dealer to double check.

[Northview]

Very interesting. I've had this problem with my S40 2.0 D SE intermittently ever since I bought it. Every now and then, the alarm triggers as I open the garage door. I haven't yet got around to asking the dealer to look at it - I've been too busy pestering them about the other persistent problems. :-(

Now that I know what might be causing it, I'll have a word with them. Thanks!