Taurus X FWD V6-3.5L (2008)
![background image](/ford/taurus_x_fwd/v6-3.5l/Page-856001.png)
Idle Speed/Throttle Actuator - Electronic: Description and Operation
IDLE AIR CONTROL (IAC) VALVE
NOTE: The IAC valve assembly is not adjustable and cannot be cleaned, also some IAC valves are normally open and others are normally closed.
Some IAC valves require engine vacuum to operate.
The IAC valve assembly controls the engine idle speed and provides a dashpot 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.
The PCM uses the IAC valve assembly to control:
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no touch start
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cold engine fast idle for rapid warm-up
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idle (corrects for engine load)
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stumble or stalling on deceleration (provides a dashpot function)
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over-temperature idle boost