hi there, i have a 1998 volvo v40 1.9se - last night at 4.am the alarm went off for no reason, i reset it and it went off again, so i left the car unlocked and it locked itself few mins later and again alarm went off, so i used the key to lock the car and all was well. is there any kind of problems or faults that can occur with the alaram system?:eek: thanks. martin

The door lock will go bad and cause the problem you have.

I found it was the sensor under bonnet..I just lock with key now no hassle

alarm backup battery on siren may at it's end of life.. s40 I don't think u can read out alarm cause. P1 and P2 chassis is the one that I know u can read out alarm cause. hope that helps