@Linchpin
If you gave some more details, someone may be able to help.:-)
Haynes do a car electronics manual showing the diagnostic plug-in points for a very large number of cars. It also list the manufacturer codes and what they mean. Check out your local Halfords where you can probably browse a copy without buying. They also sell lots of diagnostic kits (some specific, others universal) and they are not as expensive as you might think!
