What is a IAC on a Ford?
What is a IAC on a Ford? The idle air control (IAC) valve is an electronically controlled valve that allows air to bypass the throttle body. Additionally, the motor controlling the valve's position may fail in time. Signs of a dirty or failed IAC valve include engine stalling, stumbling, and/or poor idle quality. What does the p0505 Ford engine code mean? P0505 FORD Meaning. This system automatically controls engine idle speed to a specified level. Idle speed is controlled through fine adjustment of the amount of air which by-passes the throttle valve via Idle Air Control Valve IACV) and Auxiliary...