Man, the bimmerfest E39 forum is just chock full of people with this same problem on M54 cars. Few resolutions but a couple say replacing the pressure switch solved it. No reports of spun bearings or seized motors, even though most of them have driven on it.

Yeah,

Old problem who has been discussed 100 x on bimmerfest E39, E46 etc.

For the most part, you are OK. Just do some research and enjoy the reading.

My 1998 528i case was an "easy" one...leaking sensor.
Replaced the oil P sensor, all is well now...

I saw a lot of your posts. What's your thoughts on driving it before I find the fix? There seems to be a lot of different causes.

There's a places you can add a "T" onto oil pressure to read directly. It's pretty risky to drive guessing the pressure switch is reading wrong

Oil pressure switch is on the oil filter housing.
#13

https://www.realoem.com/bmw/enUS/sho...diagId=11_2201

FWIW, the oil pressure switch on these things is a commonly used part in the BMW family - like many of the sensors, i.e. air temp, dual-engine temp. etc.

And the oil pressure switch is known to be crap. I had one fail on my BMW Dakar motorcycle, giving a similar fault - low oil pressure light at low RPM. Turns out the switch fails internally and oil leaks into the contacts.

I don't recall many folk here having trouble with them but it would be my go-to first step!

the fact is that the switch works, because the error isn't always there. What is also telling is that the errors start appearing with warm (thinner) oil, at idle, which is a clear situation where low pressure can occur if there's something wrong. My guess is the sensor is fine, and you have a leaky vanos seal or a leak near the filter that causes low-flow pressure errors.

I know a switch is cheap and good to check, but my feeling is that it's probably something else.

Not quite - once faulty, the switch only works with higher oil pressure (than it is spec'ed to operate at) - and that's the issue.

At least sometimes. ;)

They do this when they start to fail. Before he starts tearing his engine apart, he should do this.

I did put in an order with FCP for a new switch ($13 shipped for the OE brand) and I think I can just park the car until I get it in.