Yeah, that is the best way to troubleshoot it if you have easy access to a code reader.
I generally use my XCalII to read codes on my Fords. I have a cheap ELM Scan that I use on non Fords, but it is an interface for my laptop, I do need to get a simple stand alone code reader as well.
00 Grand Marquis LS Premium - 97 Cougar 4.6 Sport - 89 Cougar LS - 63 Falcon 302 - 82 F-150 -
1974 Honda cb400