The Idle Air Control (IAC) valve adjusts the engine idle speed. The valve is located on the side of the throttle body. The valve is controlled by a duty cycle signal from the PCM and allows air to bypass the throttle plate in order to maintain the proper idle speed.
The IAC is located at the top of the upper intake manifold adjacent to the throttle body.
- Turn the ignition switch to the OFF position.
- Disconnect the wiring harness from the IAC valve.
- Measure the resistance between the terminals of the valve.
- Due to the diode in the solenoid, place the ohmmeter positive lead on the VPWR terminal and the negative lead on the ISC terminal.
- Resistance should be 6-13 ohms.
- If resistance is not within specification, the valve may be faulty.