Problem has existed for several years now. Dealer has had the car 3-4 times. Problem is the alert is on and off, seems to be related to external temperature at time, or if we hit a bump in the road. Goes on and off it seems at will. Usually light is not on when car is started in the am until now. It is now on persistently. Tires are good and so is tire pressure. It makes one feel very uneasy wondering if there is a problem with the tires or with the sensor or computer.