Measures capacitance of the oil:
Oil quality is determined by the electrical capacitance of the engine oil (engine oil can store an electrical charge). The charge level increases as the oil quality deteriorates. By measuring that capacity, the engine control unit (ECU) can determine the quality of the oil
In addition, Daimler discovered that oil degradation is correlated directly with its ability to conduct electric current. Therefore, Daimler has fitted V-6 and V-8 engines with a digital oil quality dielectric sensor, that is mounted above the oil pan along with an analog oil level sensor. This sensor measures changes in capacitance, which effectively is a proxy for the amount and type of contaminants and oil degradation products present in the oil. An increase in dielectric constant (less resistance to electrical flow) indicates oil contamination and degradation.
Daimler-Benz (Mercedes-Benz) has been incorporating the sensor into its vehicles since 1998.
I'm getting closer to your question but no cigar yet.
That's one of the reasons I'm not
getting a scanner/reader: you need to know what the values are supposed
to be. I've no idea what a particular "reading" means so knowing it won't do me any good. Need some kind of manual that says "xxx voltage range is 'xx' to 'yy' for example.
For example I've found:
These are the signal assignments from the oil sensor:
On/off ratio signals OK
A: Oil temperature 20 to 80%
B: Oil level 20 to 80%
C: Oil quality 20 to 80%
On/off ratio signals is greater than 80%
A: Oil temperature is greater than +160°C
B: Oil level is greater than 80 mm
C: Oil quality good
On/off ratio signals is less than 20%
A: Oil temperature is less than -40°C
B: Oil level is less than 0 mm
C: Oil quality poor
Depending on what the sensor reads, the idiot light comes up on the dash.
In answer to your question, pending a positive result, since you have a current reading
right now, measure it before and after your next oil change.
At least you will then have a base figure to refer to and then over time, measure it and record. Maybe you can infer what that number means.