If I reset a code that I dont know what it is and it doesn't come back does that mean everything is OK? Sorry this sounds so stupid.

 

Do you remember what the code was? I could look it up for you.
Did you get any other codes when you got this one?

chances are if it did not return right away it would not be a hard fault but it may have been a code that requires the car to be driven x amount of times or one that would require certain things to be met to run the test like an evap monitor if this is the case then the code will return when it tries to run the test again

my advise would be if you get the code again write down the number

 

unless it comes back or unless you remember the code I wouldn't worry about it..