I have a Countryman S All4. I changed the valve cover for a new one, and I'm now getting a "Low Oil Pressure" light. There are no codes. I removed it again and made sure everything sat perfectly, but the issue remains. What could be causing the light to come on. It was perfectly fine before. I would really appreciate suggestions. Thank you in advance.

Does the engine have the right amount of oil (and the right oil) in it?

You should find the oil pressure sensor and check the oil pressure sensor connection/wiring is good.

New oil and filter. It's at the right level. I searched online for the oil sensor location and I could only find a diagram of its location next to the oil filter, but can't seem to locate it, nor the wires physically.

The low oil pressure warning goes away when I rev the engine past 1500rpm, but then reappears when there's no engine load (between shifts and idle)

Engine sounds and works flawlessly. Using a scanner, the oil pressure measured by the ecu does fluctuate irregularly. I'm thinking somehow the sensor or wiring got banged up when I removed the valve cover. Anyone have or can take an actual picture of the sensor's location?

Thank you.

Sorry I don't have a picture for you, but I agree it sounds like maybe the sensor got knocked off a bit maybe when you were putting the oil filter cap back on, if that is near where it is located.

What brought you to change the valve cover in the first place?

The first post in this thread has pictures of an oil filter housing with a pressure switch visible in the second picture. It's out of the car, but might help you orient yourself:
R60 2012 R60 N18 oil filter housing. - North American Motoring

Thank you. I was able to locate it hidden under the turbo. Had to remove a bunch of stuff just to be able to see it. Unplugged it, cleaned it and reconnected it and the issue remains. So strange that it would fail immediately after the valve cover replacement. My thought was that I had dropped something through the timing chain opening, but there's no weird noises or anything. I'll have to figure out how to remove the sensor without pulling half of the engine apart. Hopefully it's just an air bubble in the sensor. Fingers crossed.

For future reference. The sensor is a large golden nut under the turbo.