25 Idle Air Control Motor Circuits

NAME OF CODE:
Idle Air Control Motor Circuits

WHEN MONITORED:
With the ignition ON, battery voltage greater than 10.0 volts, and the idle air control motor (IAC) active.

SET CONDITION:
The Powertrain Control Module (PCM) senses a short to ground or battery voltage on any of the four IAC driver circuits for 2.75 seconds while the IAC motor is active.

THEORY OF OPERATION:
The idle air control motor is used by the PCM to help regulate idle speed. The motor controls the amount of air allowed to bypass the throttle blade. The PCM controls the motor using four driver circuits to position the stepper motor.

POSSIBLE CAUSES:
- Driver circuit shorted to ground
- Driver circuit shorted to battery
- Driver circuits shorted together
- Failed PCM
- Shorted IAC motor

NOTE: The PCM cannot detect an open driver circuit or a stuck motor.