B4000 Regular Cab 4WD V6-4.0L OHV (1997)
Idle Air Control Solenoid: Description and Operation
The idle-speed control system controls the bypass air amount that passes through the throttle body to improve idle stability warm-up and
driveability. This system consists of the Idle Air Control (IAC) solenoid, Powertrain Control Module (PCM) and input devices.
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If the idle air control solenoid or circuit has an open or short, Diagnostic Trouble Code No. P0505, P1504, P1505, P1506 or P1507 is output.
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If the circuit is open, the idle air control solenoid will be fully closed causing rough idle, engine stalling and acceleration hesitation when cold.
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If the circuit is shorted, the idle air control solenoid will be fully open causing high idle.
