Circuit Operation

WARNING: This page is about a different car, the 2004 Mitsubishi Eclipse. However, it is still accessible from the selected car via links, so may be relevant.

When the throttle valve shaft rotates from the idle position to the fully opened position, the resistance between the TP sensor output terminal (terminal 3) and ground terminal (terminal 1) increases according to the degree of rotation.
With the ignition switch in the "ON" position, voltage at pin 78 increases from approximately 0.7 volt at closed throttle, to approximately 5 volts at wide open throttle.