Circuit Description

The ECM operates only 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:

• Idle Air Control (IAC) valve stuck or closed.
• IAC valve circuit open or short.
• AC1 open or short circuit.
• Air intake leak.