How to clear codes not simply clear "Ck Eng" light on 1998 Volvo V70

I took my car for emission inspection in PA and it failed due to codes in the computer (P0300, P0302, P0304, P0305, P0116). They told me I had to get it fixed and simply getting Auto Store to reset the Check Engine Light does not clear codes out of computer. How do I clear the coded out of computer? Thanks. (markkoski@netzero.net)

Asked by for the 1998 Volvo V70
1 answer 1 comment
The problems that set these codes need to be resolved. The P03xx codes are misfire codes that can be from bad plugs, ignition coils, vacuum leaks or running the car out of gas. The other code is a coolant temperature sensor code, probably from a thermostat that is stuck open. Either way it will require some diagnosis be a shop to accurately determine what is wrong.
Here are some shops near you that work on Volvo's: http://repairpal.com/directory?address=17327&car_brand_names=Volvo
Thanks Bret