You don't say what year your car is. On my 14.5 TCH I have two sets of tires, winter and summer. Although when I ordered up the tire/wheel kit from Tire Rack I ordered the TPMS sensors installed for what ever reason my local shop could not program them. The TPMS sensor resets each time you turn the car off. I can't definitively tell if the sensor goes by time or miles before it shows up on the dash. It never shows up during in town driving as we never drive long enough before stopping. Heading out of town on the highway it will take about 18 miles before the light comes on. It will flash for a few minutes and then go solid for the rest of the trip.