That fault code, as well as others that monitor the operation of the heater portion of the H02S, are listed as *B* rated type faults (as in you have a problem here, but will give it another try). It says that after a reset, it will not illuminate the MIL until the 2nd engine start/run event is under way. So the sensor could pass on the second attempt, an you wouldn't even know it flunked on the 1st start/run cycle.
So even if it pops up on the 2nd cycle, all subsequent start cycles will display the Mil light, until a fix is performed. You best buy a new sensor, and possibly even a matching pair, if you've got the bucks. The opposite side may have a short life left in it.