The 'check-engine' light blinks out a code when you connect a jumper across a service connector. That comes from the ECU actually measuring some kind of problem.

The 'maintenance required' light is just connected to an odometer. It's not only oil, but your entire maintenance schedule is based on 7500 mile intervals. It starts blinking a few hundred miles early to warn you. It'll come on solid 7500 miles after it was last reset.