Additional information on code readers.

By 2008 all cars will have the new CAN protocal. Some new cars have it now. Older scanners will not be able to read these cars. I don't know when Volvo will implement the CAN (Control Area Network) interface at the OBD port. Scanner manufacturers are starting to phase dual interface readers in now. The Actron 9125 is one of these per the manufacturer (had to phone them to be sure).

You only need to read Ready bits if your state inspection will fail you if they are not on. They are reset when you reset a Check Engine light and only come back on when the car passes a particular test while you are driving. This is to prevent one from driving in with the check engine light newly reset for inspection.

Of course, older readers such as the Actron 9035 will be sold at sale prices and will continue to be useful for current Volvos.