| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
Idle Air Control (IAC) valve is a step motor type and is located on air intake chamber. Intake air by-passing the throttle valve is directed to IAC valve through a hose. This allows air volume by-passing the throttle valve to be regulated.
DTC is set if idle speed continues to vary greatly from target speed. Possible causes are
- IAC valve stuck or closed.
- Open or short circuit in IAC valve circuit.
- Vacuum Switching Valve (VSV) for A/C idle-up.
- Air intake hose.