I've always thought mine might run a little rich so I may test mine too. Let me know how you end up going about testing if you do. Mine throws no codes but I do get a little soot buildup just below and around the exhaust flaps.
If you want to test for codes, you don't need to buy a scanner. You just need a paper clip.
Does your dash have an engine temp light for warning of an overheat? If so, you turn the key to the ON position, engine OFF, then put the ends of the paperclip into terminals A and B of the code scanner thingy. It will start flashing the codes on your dash light. You can google paperclip and code reading.