Low Oil Level
WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
The IPC illuminates the LOW OIL indicator when the powertrain control module (PCM) detects low engine oil level, and the signal circuit is high. The PCM only monitors the signal circuit of the engine oil level switch for a brief period when the key moves from ON to START. The IPC receives a class 2 message requesting illumination from the PCM.