Contrary to popular belief the indicator light does not reset itself. Once you put in the proper tire pressure in all tires including the spare you must reset the indicator light. The reset button is located on the driver side underneath the dash panel. Stick your on the break pedal, turn and look up. You will see the reset button. With th engine on and park break on,push and hold te button for 5 seconds. The indicator light will turn off and you are all set.

Make sure you check the spare tire too; had this problem on another model and the dealer said it was the spare which is also monitored.  Good news in case you need it one day.