Ford P0505 OBD-II Trouble Code Definition: P0505 Idle Air Control System P0505 Ford OBD-II Trouble CodeDescription: OBD Trouble Code P0505 Idle Air Control System What does the code mean? OBD-ii Code P0505 definition: The IAC (Idle Air Control) valve controls the idle speed of the engine. At idle the throttle plate is closed, of course. The […]