For the most part all of your manufacturers have their own list of codes and they also list generic OBD II codes. IF the code can be translated into a generic code it will be and if not you will get either "manufacturer specific code" or something like P1XXX, the first digit is either 1 (manufacturer specific) or it is a zero (generic code). For the most part if it is a P1 code then you could be hosed and not be able to get the code definition, not always but often enough. Obviously if it is a P0 code then you will have the definition right there on the screen or be able to get it from one of the many online sources. Pain in the ass huh? Try talking to the techs at a local Volvo dealer and tell them you have a P code, they will look at you like you have three heads. They do not deal in P codes and would not know what one was if it bit you. So, unless you buy a Volvo specific scan tool from someone like AST or Baum then you are going to have a generic tool like OTC or some of the other guys sell and it will do a host of cool shit that the specific tool will not do but it is only going to avail you if you work on a multitude of different cars. This is just a brief overview of the way it works and what is out there, investigate it yourself and you many find a scanner that suits your needs and will do it all for you. They are upgradeable and new ones come out all of the time so God only knows what is currently available.

Mark