Helpful Automotive Resources
P0505 Code: Idle Control SystemOn most older vehicles, the idle control system relies on an idle air control valve (IAC) on or near the throttle body. The IAC meters the amount of bypass air around the throttle plate to sustain the idle speed.
If the PCM perceives a problem with the idle air control system, P0506: Idle Air Control System RPM Lower Than ExpectedDiagnostic Trouble Code (DTC) P0506 stands for “Idle Air Control System RPM Lower than Expected.” It means that your powertrain control module (PCM) has detected an engine idle speed lower than the specified revolution per minute (RPM) for a specific amount of time.
Symptoms of a Bad Idle Air Control ValveThese days, most new cars have electronic throttle control (ETC), eliminating the need for an IAC. But there are still plenty of IAC-equipped vehicles on the road – and your car is probably one of them (otherwise, you wouldn’t be reading this article, would you?).