Abstract: A method and apparatus are provided for determining pressure within a tire mounted to a vehicle, wherein the tire is coupled to a tire pressure monitoring system including a sensor coupled to a transmitter, the sensor configured to sense tire pressure and the transmitter configured to transmit the sensed tire pressure to a receiver. First, a first tire pressure is sensed. Then, a calculation is made as to whether the sensed first tire pressure is greater than a predetermined pressure threshold, equal to the predetermined pressure threshold, or less than the predetermined pressure threshold. Next, an indication is provided external to the vehicle that the sensed first tire pressure is greater than a predetermined pressure range, within the predetermined pressure range, or less than the predetermined pressure range.

Abstract: A dual placard algorithm implemented in a tire pressure monitoring system which responds to tire inflation changes caused by the driver, and is thereby able to allow the tire pressure monitoring system to detect low tire pressure in dual placard applications. The algorithm automatically sets the threshold appropriate for a high placard pressure recommendation in the event the driver has inflated the rear tires to the high placard pressure recommendation. If the driver subsequently changes the rear tire pressure to the low placard pressure recommendation, the dual placard algorithm alerts the driver to manually enter a learn mode, whereupon the algorithm automatically re-sets the threshold to that appropriate for the low placard pressure recommendation only if the driver has deflated both rear tires to the low placard tire pressure recommendation.