Throttle Position (TP) Sensor
WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The TP sensor is located on the throttle body. The sensor provides throttle position information to the powertrain control module (PCM). The PCM converts the throttle position signal to a pulse width modulated (PWM) signal, and sends it to the 4WD control module to control and adjust the transfer case clutch duty cycle.