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      03-15-2011, 12:24 AM   #14
4th down; 4th quarter? Renegade.
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Drives: 09 SSII E92 M3; 12 AW X5d
Join Date: Aug 2008
Location: Pittsburgh, PA

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Originally Posted by elp_jc View Post
I suggest you educate yourself before posting such nonsense (stating facts based on something you remember reading). I dare you to find the non-existent sensor you're talking about (have fun finding it ). If there was such a sensor, you wouldn't have to reset anything after changing the oil. What you probably remember reading was what BMW calls 'condition based service', which is the algorithm that ESTIMATES when mechanical components need service. Signing off this thread for obvious reasons .

GregW already linked you the pdf in another thread:

The sensor is the same sensor that measure oil temp and is an all in one. If that document isn't accurate, then we should remove it from the site don't you think?

Here is an excerpt for you:

The oil condition sensor measures the following variables:

Engine oil temperature
Oil level
Engine oil quality

...and another:

The oil condition sensor consists of 2 cylindrical condensers. The condensers are mounted above one another. 2 metal tubes are inserted one into the other to serve as electrodes. The engine oil is used as a dielectric medium between the electrodes.

Note! Explanation of the terms 'dielectric' and 'permittivity'.

A dielectric is defined as a non-conductive material in an electrical field. The electrical field is split by an insulator. The permittivity (Latin: permittere = permit, let through) is also referred to as the dielectric conductance. The permittivity specifies the degree to which materials allow electrical fields to pass. The factor indicates by how much the voltage at a capacitor drops when a dielectric, non-conducting material is arranged between the capacitor plates.

Like I said in my previous post, it may not be as advanced as you would like, but it is an input into the algorithm of determining when your oil needs to be changed.