Circuit/System Description
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM) controls the throttle valve by applying a varying voltage to the throttle actuator control motor. The ECM monitors the actual throttle valve position using throttle position (TP) sensor 1 and 2. The ECM amplifies the TP sensor 1 signal in order to obtain a more accurate signal. The ECM monitors the TP sensor 1 amplification output whenever the ignition is ON and a closed throttle test is performed.