Low Oil Pressure
WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
The IPC illuminates the LOW OIL PRESSURE indicator in the message center when the powertrain control module (PCM) detects low engine oil pressure, and the signal circuit is low. The IPC receives a class 2 message requesting illumination message from the PCM.