1.8L (Vibe)

WARNING: This page does not describe the selected car, but rather 27 other vehicles, including the 2003 Saturn LW300, 2003 Saturn LW200, 2003 Saturn L300, 2003 Saturn L200, and 2003 Saturn Ion 3. However, it is still accessible from the selected car via links, so may be relevant.

The Powertrain Control Module (PCM) determines the correct engine idle speed by using input from various sensors and switches in order to assess the engine status and requirements. The engine idle speed is controlled by the PCM through the idle air control (IAC) valve.

The PCM has a relearn process which enables the control module to make corrections for minor variations in the fuel system. This learning ability can improve driveability. Disconnecting the battery resets the learning process. A change in the vehicle's performance may be noticed when a reset from a PCM power down occurs. Operating the vehicle under varying conditions will enable the control module to regain any lost vehicle performance.

In order to initiate the control module learning ability, warm the engine to operating temperature and drive the vehicle at part throttle with moderate acceleration. Continue to drive the vehicle while including steady cruise and idle speed operation. For the best idle speed quality several key cycles with a short drive and long idle periods is recommended.