Idle Speed/Throttle Actuator - Electronic: Description and Operation

Idle Air Control (IAC) Valve:

IDLE AIR CONTROL VALVE
The Idle Air Control (IAC) valve is located on the bottom of the throttle body. The IAC valve opens and closes the air bypass passage according to the signal from the ECM. When it opens, the air is supplied to the intake manifold. This will increase engine RPM for various engine loads.