Circuit Description

WARNING: This page is about a different car, the 2000 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.

ECM operates 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:

Idle Air Control (IAC) valve is stuck, or remains closed.
IAC valve circuit is open or shorted.
A/C switch circuit is open or shorted.
Air induction system malfunction.
Defective ECM.