This service bulletin illustrates the conditions when a TPMS warning light may illuminate, why it illuminated and how to properly initialize the system.The Tire Pressure Monitoring System (TPMS) monitors the tire pressure of all four tires indirectly using the data sent from the ABS wheel speed sensors. If the air pressure of one or more tires is too low compared with the specified value (the initial value learned by the system), the system warns the driver with the TPMS warning light in the instrument cluster and a beep sound. To allow the TPMS to operate correctly, it is essential that the TPMS be initialized to learn new conditions whenever a tire related service is performed.