Diamante Sedan V6-2972cc 3.0L DOHC (1993)
Idle Air Control Motor (Stepper Motor): Description and Operation
Idle Speed Control Servo Circuit
Location
The motor is mounted on the throttle chamber.
Purpose
The Idle Air Control (IAC) motor maintains idle speed by compensating for loads placed on the engine.
Operation
The IAC motor is a stepper motor that regulates the amount of air taken in through the bypass circuit of the intake manifold by opening and
closing the motor valve located in the air passage.
The ECM supplies voltage in one polarity direction, which turns the motor in a particular rotation. The motor shaft is connected to a screw that
when turned, opens the passage by moving the pintle. When the ECM reverses polarity, the passage is closed in the same manner.
The ECM uses several sensor inputs to determine the operating condition of the engine and the loads being placed on it. The ECM adjusts the idle
for air conditioning and automatic transmission loads, and controls fast idle for cold start. The ECM uses the IAC motor to make all of the
adjustments to idle speed.
