I have a 57 2.0 tdi 170 and get the low oil level intermittently but usually come on after a long drive of an hour or more. I could then park the car on the drive and the next morning with a cold engine, the warning will appear when I switch the ignition on and will remain on. If I don't start the car and check the level on the dip stick, it's bang on the max mark. Replace the dipstick and turn ignition on again, the warning has gone. It will probably remain normal until I drive for an hour or so again.
Anybody any idea what's going on?