Your nearest Autozone parts store offer a free service to pull the codes for you. For the average DIY a scantool is WAY too expensive to be practical. Ck.
http://www2.autozone.com/servlet/UiB...eck_engine.jsp
for a nearby store . Lots of them in New Jersey. Remember a scantool only points in the right direction, it doesn't give answers.
Retired tech
Rick