I haven't seen any other forum threads that describe my exact issue. I have a 2002 S60 that I bought in 2006. Off and on while I've owned it, I've gotten the "alarm system triggered" message, but I never heard the alarm go off and there was no apparent entry. This car is a little quirky, so I didn't worry about it. Also the trunk of the car sometimes randomly unlatches without being triggered, so I thought there might be some connection between the two.

Recently I've gotten the "Alarm System Service Required" message consistently. If I roll down the window, lock the car, and then pull up on the lock, the red light will blink but the alarm doesn't sound. I can, however, get the siren to go off with the panic button.

Any ideas what's going on?

 

The alarm module is probably failing. Over time the alarm battery fails and often leaks onto the alarm module. You can find the module on the left frame in front of the tire.