F 150 Super Crew 2WD V8-4.6L SOHC VIN 6 (2003)
Hitachi Idle Air Control (IAC) Valve Assembly With Air-Assist Injectors
On applications with air-assisted injectors, the IAC valve (Figure 124) also supplies a small amount of air into the path of the fuel injectors. The jet of
air causes an increase in fuel atomization at low speed and light load conditions.
NOTE: The IAC Valve Assembly is NOT ADJUSTABLE and CANNOT BE CLEANED.
The IAC valve (part of throttle body assembly) has an internal diode on some applications. If the internal diode is measured in crossed terminal
position with a digital multimeter, there will be an incorrect or negative reading. It is important that the mating component and harness connectors are
correctly oriented. Diagnostic procedures emphasize this importance.
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 dash pot function)
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Over-temperature idle boost.
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Air Assist to Injectors.
