DTC P0507: Idle Control System - High Rpm (With Electronic Throttle Control): Description
WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, and 2002 Chevrolet Tahoe. 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 these inputs in order 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, this DTC will set.