Sinyk

That's good to hear. So far I've noticed with highway driving, my pressure stays pretty well at or slightly under the 275 kPa (40 psi) line. When it's cold it idles above 40 and if i accelerate, it goes up to almost the 3/4 line. When the engine is fully warmed up and idling it looks like it sits closer to 30psi now, not like the 20 or slightly below the 1/4 line it did before. So far I have not seen the CEL return so that makes me happy. I am most concerned about it when camping season comes and I'm towing my RV. I will probably give it another oil change when camping season gets going.

Well I did the oil change, switching to a PF63 and Synthetic 5W-30 Mobil 1. When cold with acceleration, my oil pressure goes up to the 3/4 line. When warm, it sits right around the middle. I didn't drive the truck for a long time this weekend, but so far so good. The pressure was better after the previous oil change with the PF48 though, so time will tell if this holds.

The confusing thing is they reissued that TSB multiple times. PIP5276C said to use a UPF48R filter instead of a PF48e, but then they revised it to say don't and just use the PF48, and eventually that you need to replace a ton of stuff due to oil consumption. Since the PF63 has been used by numerous people for years without trouble, then i probably will start there. I think the UPF63R has a way higher bypass pressure, like 33psi, and the filters are double the price.

Yes I replaced the screen under the sensor and cleaned out everything around there that i could. I'm close to an oil change, so I might as well. Seems cheaper to try that than dropping my oil pan or replacing the oil pump. From what I have read, lots of people have used the PF63 with no issues on this truck/engine.

I have a 2012 5.3L LC9 Sierra that has been dealing with the P0521 code for at least a year. When it first appeared, I took it in and the mechanic switched to a PF48 filter from whatever was on there before, and my low oil pressure issues went away. After about 3000 km, the oil pressure dropped again, so I decided to replace the Oil Pressure Sensor with a new GM one. That didn't fix the issue either. Someone told me this could be the oil pick up o-ring, the oil pump, or worse. Most of my driving is short distances, so the check engine light goes off after a few days, but always comes back. My question is, would changing the filter from the PF48 to the PF63 increase the oil pressure since the bypass pressure is higher (22 psi vs 15 psi)? Has anyone done this to fix this issue?