Circuit Description

WARNING: This page is about a different car, the 2002 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.

ECM operates Idle Air Control (IAC) valve to perform idle-up and provide feedback for target idling speed. DTC is set when idle speed continues to vary greatly from target speed. Possible causes are:

IAC valve is stuck or remains closed.
IAC valve circuit is open or shorted.
A/C signal circuit is open or shorted.
Air induction system malfunction.
Defective Positive Crankcase Ventilation (PCV) valve or hose.
Defective ECM.