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 throttle actuator control (TAC) system uses 2 throttle position (TP) sensors to monitor the throttle position. The TP sensors 1 and 2 are located within the throttle body assembly. Each sensor has the following circuits:
- A 5-volt reference circuit
- A low reference circuit
- A signal circuit
Two processors are also used to monitor the TAC system data. Both processors are located within the engine control module (ECM). Each signal circuit provides both processors with a signal voltage proportional to throttle plate movement. Both processors monitor each other's data to verify that the indicated TP calculation is correct.