2009 Suburban Low Oil Pressure

I saw a few trouble codes for lo oil pressure, the circuit description I listed below is for p0521, you can see how the circuit works. Some makes and models you could use an analog gage in place of the oil pressure sending unit to double check the oil pressure reading. The old rule of thumb was 10 psi for every thousand rpm. You need to use the proper oil pressure specs, which I don't have, in front of me. I did see a service bulletin about remanufactured engine, goodwrench, having this problem. If you want the bulletin, I'll post it? good luck

Please post he service bulletin. I was looking into the manual gauge to verify pressure. Doesn't seem as easy as I was hoping for. Thanks

Here is part of tsb.

Here is another part.