Circuit Description
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 stuck, or closed.
- IAC valve circuit is open or shorted.
- A/C switch circuit is open or shorted.
- Air induction system malfunction.
- Defective ECM.