Tire maintenance light stays on but pressure in tires ok. What's wrong? on 2011 Nissan Altima

My tire was low and the tire maintenace light came on. Had all four tires pressure checked and corrected. Light went off. Next day light came back on. Had tires checked again. Pressure was still ok. Light off. Next day, tire maintenance light on again. Had tires checked again. Still ok. What could be wrong?

Asked by for the 2011 Nissan Altima
you have to reset them after properly inflation.
2 answers
this should be covered under warranty but have you ck'd your spare tire pressure also.