Idle Speed: Description and Operation

CIRCUIT DESCRIPTION
The Throttle Actuator (TAC) motor is controlled by the TAC module, using various inputs from the Powertrain Control Module (PCM) which are communicated across serial data. The DC motor located on the throttle body drives 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 idle speed, the TAC module commands the throttle plate open allowing more air to bypass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this DTC sets.