My 05 525d is displaying a message saying "Oil Level Sensor Faulty" has anyone else had this problem and if so was sensor expensive and how do you replace same.

 

I haven't had the message appear, but as I read these documents it doesn't appear to be a big job, although I'd bet money that you have to go to the dealer or an independent shop and have them program the module for you.

BMW-oil-sensor.pdf

Oil_Sensor.pdf

The part for my car costs $200.

Good luck.