F 250 4WD Super Duty V10-6.8L VIN Z CNG (2003)
Idle Speed/Throttle Actuator - Electronic: Description and Operation
IDLE AIR CONTROL VALVE
Nippondenso Idle Air Control (IAC) Valve Assembly
Hitachi Idle Air Control (IAC) Valve Assembly With Vent/Filter
The idle air control (IAC) valve assembly (Figure 122) and (Figure 123) controls engine idle speed and provides a dash pot function. The IAC valve
assembly meters intake air around the throttle plate through a bypass within the IAC valve assembly and throttle body. The PCM determines the
desired idle speed or bypass air and signals the IAC valve assembly through a specified duty cycle. The IAC valve responds by positioning the IAC
valve to control the amount of bypassed air. The PCM monitors engine rpm and increases or decreases the IAC duty cycle in order to achieve the
desired rpm.
