Idle Speed/Throttle Actuator - Electronic: Description and Operation

Idle Air Control (IAC) Valve:

PURPOSE
The Idle Air Control (IAC) Valve, mounted on the intake manifold, is used to provide a stable idle under normal operating conditions.

OPERATION
The IAC Valve is powered by ignition switch terminal Ign. 1 and receives power anytime the ignition is turned ON. The Programmed Fuel Injection Electronic Control Module (PGM-FI ECM) controls the ground circuit. The valve is used to correct idle speed when out of normal operating parameters. Idle speed is modified by allowing air to bypass the throttle plate through the IAC Valve. By varying the current of the signal to the IAC Valve the PGM-FI ECM is able to control the position of the IAC Valve plunger.