Volvo Cars Volvo won't replace defective parts Rockleigh, New Jersey

The SRS sensor in our Volvo has needed replacement for no apparent reason twice in two years, a $650 job, $485 of which is for the part.  Our mechanic thought this was unusual and called Volvo to request replacement of this part.  They said no.  In all our years of car ownership, we have never encountered this situation.  Since when is an SRS sensor supposed to be replaced every two years?  Clearly, Volvo has some quality control problems, as well as some customer relations issues.  Hondas and Toyotas are looking better and better to us.