Electrical connector
O ring
Pintle
The engine idle speed is controlled by the idle air control (IAC) valve. The IAC
valve is on the throttle body. The IAC valve pintle moves in and out of an idle
air passage bore to control air flow around the throttle plate. The valve
consists of a movable pintle, driven by a gear attached to a two phase
bi-polar permanent magnet electric motor called a stepper motor. The stepper
motor is capable of highly accurate rotation, or of movement, called steps.
The stepper motor has two separate windings that are called coils. Each coil
is fed by two circuits from the powertrain control module (PCM). When the
PCM changes polarity of a coil, the stepper motor moves one step. The PCM
uses a predetermined number of counts to determine the IAC pintle position.
Observe IAC counts with a scan tool. The IAC counts will increment up or
down as the PCM attempts to change the IAC valve pintle position.
valve is on the throttle body. The IAC valve pintle moves in and out of an idle
air passage bore to control air flow around the throttle plate. The valve
consists of a movable pintle, driven by a gear attached to a two phase
bi-polar permanent magnet electric motor called a stepper motor. The stepper
motor is capable of highly accurate rotation, or of movement, called steps.
The stepper motor has two separate windings that are called coils. Each coil
is fed by two circuits from the powertrain control module (PCM). When the
PCM changes polarity of a coil, the stepper motor moves one step. The PCM
uses a predetermined number of counts to determine the IAC pintle position.
Observe IAC counts with a scan tool. The IAC counts will increment up or
down as the PCM attempts to change the IAC valve pintle position.
Idle Air Control Valve (IAC)
