just visited local AutoZone for the OBD scanner code and they adviced the Check Eng light is on due to computer asking for maintenance (air, oil, fluids) at some 77 or 78k interval - it's some kinds of "hey dude, do the maintenance" reminder
car is a mazda -98 with 78k miles and I assume that I can simply disconnect negative terminal of battery (ground) to reset computer or do I have to actually have the code reset with a scanner or some diagnostic screw terminal on the instrument panel?
reason the light does not apply is that all the items have been done, usually at every 3 to 5k intervals, since new.