Theory Of Operation
WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
The TCM monitors the Input Speed and Output Speed Sensors for electrical malfunctions. This monitoring is done by comparing the sensor voltage (measured across a shunt resistor) to a high and low signal voltage threshold. If the high or low voltage threshold is exceeded, a DTC is set for the specific sensor.