Sunday, late at night when siren went off on our 2003 Volvo S80 (Elite), we thought it was one of the stray cats in the neighborhood jumping up on the car. It went off several times, but didn't think too much of it as there are several cats.

Monday, at work, the Security guard said siren kept going off and notified my husband. Also told him his State Inspection sticker was out of date.

Monday night at home, had to leave car unlocked as siren kept going off.

Tuesday at Volvo dealership in Houston, the "codes" indicated one of two possibilities; door latch or siren to be replaced.

Service Adviser suggested replacing door latch first rather than both to see if that would do the trick. Needed State Inspection and, turns out, needed a new battery to pass State Inspection. Was the problem solved? Guess not, as when I went home that night, siren went off using the remote key. Took the car out again later yesterday evening and asked my husband "Should I set the alarm?" "Why not use the key to see if that'd make any difference."

Seems to have done the trick for last night, but today after going back to the dealership (was told I needed to put 50 continuous driving miles on the new battery before taking the State Inspection test), I told the Service Adviser about the continuing siren problem. He shook his head.

After passing the State Inspection test, I spoke with one of the Swedish Service Technicians and he said that there is a back up battery for the siren. Maybe that could be it. But he was a bit baffled as he thought that it would have shown up in the codes run yesterday.

My question is: Would the back up battery for the siren show up in the codes?

Would frayed or faulty wiring cause the codes to indicate the door latch or siren needed repair when it might only be a back up battery for the siren -- or faulty wiring?

Thanks for your advice in advance.