DTC P0506: Idle Speed - Low: Description

PCM controls idle speed with Idle Air Control (IAC) valve, located on throttle body, to a calculated RPM based on sensor inputs and actual engine RPM. PCM moves IAC valve in or out to vary amount of airflow into intake manifold and thus decrease or increase idle RPM.

PCM commands IAC in counts. A higher count, allows more air to by-pass throttle plate (higher idle).