The Idle Air Control (IAC Valve) regulates the velocity of the vehicle when it is idling. The Minimum Valve (IAC) is controlled by the PCM (Power Train Control Module) and this allows around the accelerator plate only a low percentage of air. This portion of air is what inspects the idle speed.
The Idle Air Control Valve has an opener, which makes movements to open and close the air passage. The greater the amount of air that the minimum valve provides around the throttle plate, the more inactivity there is.
The IAC Valve is used by the Powertrain Control Module so that the idling speed is correct as requested by the vehicle. The voltages of the circuits of the Idle Air Control Valve are constantly monitored by the PCM and, in case a voltage is detected incorrectly in one of the circuits, the DTC code P0505 OBD2 is established.