Circuit Description

The ECM operates only Idle Air Control (IAC) valve to perform idle-up and provide feedback for target idling speed. A Vacuum Switching Valve (VSV) is added for idle compensation when A/C is operated. Code is set when idle speed continues to vary greatly from target speed. Possible causes are:

• IAC valve stuck or closed.
• IAC valve circuit open or short.
• VSV for A/C idle-up.
• Air intake leak.