Tire Pressure Transponder
WARNING: This page is about a different car, the 2008 Dodge Magnum, 2008 Dodge Charger, and 2008 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
A transponder, sometimes referred to as a trigger module, is located in three of the four wheel wells (behind the wheelhouse splash shields) of a vehicle equipped with Premium TPM. These transponders are used to provide the Wireless Ignition Node (WIN) with the location of the tire pressure sensors on the vehicle. A fourth transponder is not necessary in the remaining wheel well due to the process-of-elimination theory. Once the system knows the location of the first three sensors it assumes the location of the fourth tire pressure sensor. On this vehicle, there is no transponder in the left rear location.