Circuit Description

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.