95 4700 T444E Oil/Water light

Today the Oil/Water light came on in my 95 4700. Oil pressure gauge was in between 35-40 psi at 2000 rpm where it usually sits, when warm at Idle it's a little under 20. That's where it always sits, the coolant temp was a hair above 180* where it usually sits as well. Both the coolant level and oil level are good. Oil and coolant are clean as well, no signs of mixing. The light went out when I got off the Highway. What would make this light come on?
Thanks

 

I retrieved codes using the Engine Diagnostics button on the dash and got 111 for active codes. For Inactive I got 124,221,622,and 313. 313 is Engine Oil Pressure below warning level. Is there a sensor for the light separate from the gauge? Where is a test port on the engine that I could hook a mechanical oil pressure gauge up to?

 

I verified, there is an oil pressure line connecting the gauge to the HPOP reservoir, the gauge is mechanical and doesn't sweep when the key is turned on. I was thinking about removing the sensor and installing a mechanical gauge to verify pressure. I also found a diagnostic manual online that should help trace down a wiring fault in the system. I removed the connector at the sensor and it's clean there and I have 5V on wire A but all I could get on wire B was 200 ohms. I was going to trace them back to the next connection, it looks like they go toward the starter. Do you know where the next connector with these wires in it would be?

 

No, I don't which one of the modules under the hood is the ECM?