It takes at least 2 driving cycles to reset the electronic control unit
(ECU).  There are specific parameters that define a driving cycle, such as
sitting for X hours and having the coolant temp cool below Y degrees, then
driving for Z miles with the coolant temp getting above A degrees, and the
speed getting above C miles per hour for D minutes.  The trick is letting
the car sit long enough (overnight is usually long enough) and then driving
it far enough and then repeating the pattern.  A week is usually, but not
always long enough.