I have had several issues with the Tire Pressure monitor. I purchased new snow tires, new rims, and had sensors added, so I would not have to deal with the reset issue everytime I had my tires changed. When I had the snows put on in November, I left the dealership, to have the light come on after about 30 miles. I took it in, they reset it, all was good. Until just last week, I had my summer tires put back on, and I've had to take the car in 2 times to reset the tpms system. The service people do not know why this is happening.