My wifes 89 535i, shows the oil pressure message only when the car starts, then when you shut it off. Doesn't stay on when driving. Can someone give me the location of the sensor? I looked by the oil pan, and oil filter and can't see it. Maybe a picture would be good. According to the Bently book it's by the oil filter on a 525, or on the pan for an 535, I can't find it. It's been doing this since I bought the car in Oct, doesn't seem like I have low pressure.