ljwitaker2002, I started a new thread for you - the 2007 thread you found contains incorrect information, so let's start from scratch.
Did you change the oil pressure sensor or the oil level sensor - they perform very different functions.
There are several DIC messages you will see concerning engine oil. I believe you have "Check oil level" and "Change oil soon".
Proper oil level is in the middle of the dipstick hashmarks - < == ADD XXXXXXXXXX OPERATING RANGE========= . If the level is there, engine off for 5 minutes, then the oil level sensor may be faulty. It's in the front side of the oil pan and will set a trouble code if it or the electrical circuit is bad.
The "Change oil" message is triggered by the OLM and you can reset it each oil change by calling up Oil Life in the DIC and holding the INFO RESET button for 5 - 10 seconds. Oil Life then goes to 100%.
Read up on oil level and oil life way up ^^^ in the black bar - Cadillac Technical Archive. For trouble code work, your car has its own built-in code scanner. Study the correct parts of the sticky post just above this thread - "How to pull codes".
Ljwitaker2002, I see Submariner has already jumped in to give you helpful advice, and please don't hesitate to contact me as well if you have any lingering questions after consulting the forum archive as suggested. I'm reachable via email at [email protected]!
It sounds like you may be confusing oil level and oil life. Oil level is monitored by a level sensor. Oil life is monitored by the PCM.
The only thing I would add to what Sub said is that you MUST reset it (OLM) each oil change. Cadillacs are truly THE "smart car" with all the onboard diagnostics and monitoring, but they don't know when the oil was changed unless you tell them.