Circuit Description
WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.
The Electronic Throttle Control (ETC) System uses various inputs from the powertrain control module (PCM). This system uses the inputs to control the idle speed through serial data circuits to the throttle actuator control (TAC) module. The DC motor, which is located on the throttle body, activates the throttle plate. In order to decrease idle speed, the TAC module commands the throttle closed, reducing air flow into the engine, and the idle speed decreases. In order to increase the idle speed, the TAC module commands the throttle plate open, allowing more air in order to bypass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, DTC P0506 sets.