Is the code permanent or does it clear after so many cycles? If I'm on the road and can't get to a dealer, I'm going to have to top it off. That, in theory, corrects the error condition. In that circumstance, the best I'll be able to do is read the code and print a report from the scan tool. I would be very happy (or not) to have the light go on while I'm driving home from work, because the dealer is on the way.You don't need the light to be on, just that it sets a code. That is the criteria. You can tell them the light came on and show them a pic if you want but you need the code stored. You could have been due for an oil change when it came on or just did an oil change early and have clean oil when you bring it in. It's not their business how soon you like to change your oil as preventative maintenance. Only the code needs to be set when you bring it in. It's not rational or expected that someone drive around with a low oil light on the dash and possibly do engine damage until they can get to or make an appointment and bring the car into the dealer!