Steve. Thanks for the reply. I don't notice any difference in how it's running now that the check engine light came on. If not for the light I wouldn't know there was a problem. I am unfortunately away from the machine right now but can get back to it tomorrow. So are you saying what I was doing wrong was going into the options menu, as in the normal settings, but if I hold the mode button longer it will go into another menu where I can access diagcode? I did see the codes listed in the manual and that's what I was trying to find so I could reference it and at least get an idea of what is going on.