Circuit Description

This test determines if idle control system is maintaining the proper idle speed. The IAC system controls idle speed by allowing a certain amount of air to by-pass the throttle body (throttle plate closed during idle) through the IAC valve. The PCM controlled IAC motor moves a pintle in and out of IAC valve, varying the amount of air entering the intake manifold. DTC will set when engine idle speed is greater than the desired idle speed for 15 seconds.