Patent ID: 7941257

Claim:
A tire pressure monitoring system comprising: a plurality of wheel units respectively associated with tires normally installed on a vehicle, each wheel unit including a sensor for generating a sensor signal indicative of a parameter of the tire which varies compared to a threshold when the tire is installed on the vehicle and is rolling while the vehicle is moving and which remains constant compared to the threshold when the tire is stationary irrespective of whether the vehicle is moving, a processor for processing the sensor signal to determine whether the tire is rolling or is stationary, and a transmitter for transmitting a tire signal including an indication of whether the tire is rolling or is stationary; and a controller to be installed in the vehicle, the controller including a receiver for receiving the tire signals from the wheel units, the controller further receiving a speed signal indicative of whether the vehicle is moving or is stationary, wherein the controller processes the tire signals and the speed signal to determine if any of the tires is stationary while the vehicle is moving, wherein the controller generates a warning signal indicative of an unmonitored tire installed on the vehicle in place of one of the tires upon determining that the one of the tires is stationary while the vehicle is moving.