Idle Speed/Throttle Actuator - Electronic: Adjustments

Engine idle speed is controlled by the PCM through the IAC valve, mounted on the throttle body.

The controlled or desired idle speed for all engine operating conditions is programmed into the PCM. If power to the PCM is interrupted, the PCM has to relearn idle control.

The minimum throttle valve position is set at the factory with a stop screw. Because of low internal friction, provisions for slight production variations, and the various altitudes production vehicles operate, the calibrated air rate at the minimum throttle position is too low to allow most engines to idle. The throttle stop screw is tamper resistant and should not be adjusted.

The PCM resets the IAC valve pintle position only after a power is shut off. During the reset, the PCM commands the IAC valve pintle to move in to the seated position (to establish the zero count position), and then back out to the desired position.

The IAC valve also can be reset without driving the vehicle by using the following service procedure:
1. Disconnecting the battery.
2. Use the service tool (Saturn Tool) SA9195E and run the pintle in.
3. Use the PDT portable diagnostic tester (Scan tool) and commanding the pintle in.