Change Oil Soon
WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.
The instrument panel cluster (IPC) illuminates the CHANGE OIL SOON message in the message center when the engine control module (ECM)/powertrain control module (PCM) determines that the engine oil needs to changed. The ECM/PCM sends a class 2 message to the IPC requesting warning message illumination. After the oil is changed, reset the engine oil monitor. Refer to GM Oil Life System - Resetting in Maintenance and Lubrication.