General Description

The Idle Air Control (IAC) valve is attached to the underside of the throttle body with four bolts. The IAC valve enables the Powertrain Control Module (PCM) to easily control engine idle speed by precisely metering the engine's air intake at closed throttle.

The IAC valve opens and closes the idle air (bypass) passage according to signals from the PCM. The IAC valve contains an engine coolant passage that enables the IAC valve to operate more efficiently at cold temperatures. The PCM determines the correct engine idle speed by using input from various sensors and switches in order to assess engine status and requirements.