house alarm sounding no fault seen?

hi my house alarm is a accenta 8 mini the box on the outside wall was sounding and making a clicking noise the alarm was not armed at the time it would not go off at the key pad I turn off the alarm power opened the cpu box and closed it again and punched in my code at the key pad this stopped both the outside box and the pcu from going off the powers still off any help would be great thanks