Theory Of Operation
WARNING: This page is about a different car, the 2012 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
The Tire Pressure Monitoring (TPM) Transponder is used to automatically learn the location of each wheel sensor on the vehicle. The module is controlled and activated in sequence by the Wireless Control Module (WCM) over a LIN bus. When activated, the TPM Transponder generates a 125 KHz signal of sufficient field strength to trigger the Tire Pressure Monitoring (TPM) Sensor and force a Radio Frequency (RF) transmission from the TPM Sensor.